feature: the router keeps its metrics in PostgreSQL, serves them for an OpenTelemetry Collector and pushes them over OTLP.

feature: vpn-config-edit shows and changes the router's configuration.
fix: web.status_content is basic by default.
2026-10-25 14:57:47 +01:00 · 2026-10-25 13:29:12 +01:00 · 2026-10-25 13:09:57 +01:00 · 2026-10-25 13:08:08 +01:00 · 2026-10-25 12:25:57 +01:00 · 2026-10-25 11:37:43 +01:00
24 changed files with 1787 additions and 233 deletions
@@ -27,28 +27,40 @@ port is reachable from the external interface only when it is in `exposed_ports`
 in `DOCKER-USER` are not touched, because the package owns only its own chain. Restarting Docker
 restores the rules. The rules cover IPv4 only.

-## ADR-2: A small status web service, bound to the internal address
+## ADR-2: A small status web service, on the interfaces web.listen chooses

 Status: Accepted

 Context: The router has no way to see its state without a shell. A check from the protected
-network, by a person or by a monitor, needs a page or an endpoint. The router is an
-internet-facing host, so what the service shows and where it listens matter.
+network, by a person or by a monitor, needs a page or an endpoint, and so does the platform that
+deploys the router, which reaches it on its public address. The router is an internet-facing
+host, so what the service shows and where it listens matter.

 Decision: The `vpn-router-web` unit runs one Python script on the standard library's
 `http.server`, with the package's own modules and the Python packages of the Ubuntu archive that
-the package depends on, and no web framework. It listens on the address of the internal interface and on
-`web.port`, 7081 by default, and is on unless `web.enabled` is `false` (ADR-7). `/` is for
-people, in plain text for `curl` and `wget` and as a Tailwind CSS page for a browser, and
-`/status` is the same status as JSON. It shows the state of the services, the package version
-and the state of the site-to-site, road-warrior, OpenVPN and WireGuard features, and nothing from
-the configuration. `vpn-router-setup` opens the port on the internal interface in UFW and writes
-the features and the facts it resolves to `/run/vpn-router/web.json`.
+the package depends on, and no web framework. It listens on `web.port`, 7081 by default, on the
+address of the internal interface, of the external interface or of both, as `web.listen` sets
+(`internal`, `external` or `both`, the default), with a server for each address, and is on
+unless `web.enabled` is `false` (ADR-7). `/` is for people, in plain text for `curl` and `wget`
+and as a Tailwind CSS page for a browser, and `/status` is the same status as JSON. Both show as
+much as `web.status_content` says, since the router is reachable from the internet and the
+operator decides how much it tells strangers: `basic`, the default because it tells the least,
+the overall status and the Client IP, `standard` also the package versions and the number of
+active and other services, and `full` also each service and the state of the site-to-site, road-warrior, OpenVPN and
+WireGuard features. The Client IP is the address the request came from, through the trusted
+proxies, so a person can see the address the router sees. Nothing comes from the configuration.
+`/status` names its content, so clients such as manage-ui and the Router Manager show what it
+has. `vpn-router-setup` opens the
+port on both interfaces in UFW, so the choice of `web.listen` is made by the service alone, and
+writes the features and the facts it resolves to `/run/vpn-router/web.json`.

-Consequences: Nothing outside the internal network can reach it, since it listens on the internal
-address only and the firewall opens the port on the internal interface only. `/` and `/status`
-have no authentication, which is acceptable because they are read only and show no
-configuration. It runs as root, because `swanctl` and `wg` need it, with `NoNewPrivileges`,
+Consequences: By default the service is reachable from the internet on the external address;
+`web.listen` set to `internal` keeps it to the internal network. It serves plain HTTP itself;
+HTTPS is Caddy's (ADR-21), so on the plain HTTP port the passwords of `/auth` and the tokens
+cross the internet unencrypted. A change of `web.listen`
+needs no run of setup, since the firewall does not depend on it; the package's upgrade runs
+setup, which writes the rules. `/` and `/status` have no authentication, which is acceptable because they are
+read only and show no configuration. It runs as root, because `swanctl` and `wg` need it, with `NoNewPrivileges`,
 `ProtectSystem=strict`, `ProtectHome` and `PrivateTmp`. The Tailwind style comes from a CDN, so a
 browser on a network without internet shows the unstyled page, and `curl` is unaffected.

@@ -60,7 +72,7 @@ Context: Clients such as the Router Manager, and people with `curl`, need the co
 the users and the groups of the router, which `/` and `/status` must not show. Both people and
 programs sign in with a user of the directory. A secret shared with the platform that deploys
 the router would let whoever holds it, and every copy of the deployment's state, make tokens.
-The service listens on plain HTTP on the internal network.
+The service listens on plain HTTP.

 Decision: `/config`, `/users` and `/groups` need a JWT in an `Authorization: Bearer` header,
 HS256, verified with `hmac` and `hashlib`; no other algorithm is accepted. The key is
@@ -158,22 +170,23 @@ and the holders of an admin token manage users.
 Status: Accepted

 Context: The status page is the tool to see a problem of `vpn-router-setup`, so it must run
-whatever state setup is in, also before setup has run and while it fails. The internal address,
-`web.port` and `web.enabled` can change at any time.
+whatever state setup is in, also before setup has run and while it fails. The addresses,
+`web.listen`, `web.port` and `web.enabled` can change at any time.

 Decision: The service depends on nothing to start and does not end on its own. A discovery
-thread works out, every 30 seconds, the internal address from `vpn-router.json` as
-`general.mode` directs, with the discovery code in `vpnrouter_net.py`, which `vpnrouter.py` uses
-too, and `web.port` and `web.enabled` from the same file. It runs the HTTP server in a thread of
-its own at that address and port, stops it and starts a new one when they change, and runs none
-while the service is disabled, the address is not known or it cannot be bound. Each request
+thread works out, every 30 seconds, the addresses of the interfaces `web.listen` names from
+`vpn-router.json` as `general.mode` directs, with the discovery code in `vpnrouter_net.py`,
+which `vpnrouter.py` uses too, and `web.port` and `web.enabled` from the same file. It runs an
+HTTP server in a thread of its own at each address and the port, stops one and starts a new one
+when they change, and runs none while the service is disabled or no address is known; an address
+that cannot be bound is tried again the next round. Each request
 reads the signing key and `vpn-router.json`, and the features and resolved facts from
 `web.json`, which setup writes when it applies the configuration, so the service shows what setup
 applied; while that file is missing the router shows no features. The unit is not
 ordered after `vpn-router-setup`, and setup does not restart it.

-Consequences: The status page answers as soon as the internal address exists, whatever state
-setup is in, and follows a changed address, port or `web.enabled` within 30 seconds without a
+Consequences: The status page answers as soon as an address exists, whatever state setup is in,
+and follows a changed address, `web.listen`, port or `web.enabled` within 30 seconds without a
 restart. A new signing key applies to the next request. The interfaces are read every 30
 seconds, which costs a few `ip` commands.

@@ -209,9 +222,9 @@ router's `/auth`, keeps their tokens in a server-side session in PostgreSQL behi
 session's access token, refreshing it as needed; it holds no logic of the router's own and no
 key of it. It reads its settings from `/etc/vpn-router-manager/manager.json` at each request; on
 the router the settings not given come from `vpn-router.json`, and it listens on the internal
-address like the status web service, with the same discovery thread. `vpn-router-setup` opens
-the manager's port on the internal interface while the manager is installed, so the firewall
-stays in one place.
+address, the external address or both, as its own `listen` sets, like the status web service,
+with the same discovery thread. `vpn-router-setup` opens the manager's port on the internal and
+the external interface while the manager is installed, so the firewall stays in one place.

 Consequences: The router needs no Node.js; the package needs only `python3` and packages of the
 Ubuntu archive. Tokens never reach the browser, and sessions survive a restart of the manager.
@@ -320,8 +333,8 @@ within 15 minutes; a successful bind clears the count; `vpn-router-user unlock`
 `/auth` answers the same 401 for a wrong name, password or code and for a locked or disabled
 user. `/auth` and `/auth/refresh` allow 10 calls a minute per client address, counted in memory,
 and answer 429 with `Retry-After` beyond that. The client address is the peer, or the last
-`X-Forwarded-For` entry for a peer in `web.trusted_proxies`, by default the address the service
-listens on, where a manager on the router calls from.
+`X-Forwarded-For` entry for a peer in `web.trusted_proxies`, by default the address the call came
+in on, which is the address a manager on the router calls from.

 Consequences: One lockout covers OpenVPN and `/auth`, kept by slapd alone. Someone who knows a
 user name can lock the user out for 15 minutes at a time. The rate limit restarts with the
@@ -454,8 +467,8 @@ e-mail address can be added later without changing their classes; VPN users get
 used.

 Consequences: The schema check stays strict. New attributes extend `vpnRouterAccount`, and their
-OIDs continue the arcs. Nothing reads `vpnRouterScope` yet. The OID must never be reused for
-anything else.
+OIDs continue the arcs. The scope `service` marks a service account (ADR-23). The OID must never
+be reused for anything else.

 ## ADR-20: Users manage their own account through /account, proving who they are again

@@ -480,3 +493,87 @@ Consequences: slapd's `otp` overlay accepts each code once, so a change right af
 needs the next code. Changing the password revokes the user's refresh tokens, so the user's
 Manager session ends with its access token. An enrolled user who has lost the authenticator
 needs an administrator.
+
+## ADR-21: Caddy from the Ubuntu archive serves HTTPS with a certificate from Let's Encrypt
+
+Status: Accepted
+
+Context: The status web service and the Router Manager are reachable from the internet (ADR-2),
+and `/auth` and the Manager's sign-in carry passwords. Both are small servers on the standard
+library's `http.server`, which would need certificates, their renewal and a TLS setup of their
+own. Browsers trust a public CA, not the router's.
+
+Decision: Caddy, the `caddy` package of the Ubuntu archive, is the HTTPS proxy. While
+`https.enabled` is `true` (the default) and `wan.local_fqdn` is set, `vpn-router-setup` writes
+`/etc/caddy/vpn-router.Caddyfile`: a site for `wan.local_fqdn` on `https.web_port` (7444) for the
+web service and, while the Router Manager is installed, one on `https.manager_port` (7443) for
+the manager, each passing calls to the service on `127.0.0.1`. Caddy obtains and renews the
+certificate from Let's Encrypt with the HTTP challenge on port 80, which the firewall opens on
+the external interface; `auto_https disable_redirects` keeps port 80 to the challenge. The
+package's drop-in for `caddy.service` points it at that file and keeps it from starting before
+the file exists, so `/etc/caddy/Caddyfile`, a configuration file of the `caddy` package, is left
+unchanged. Both services always listen on `127.0.0.1` as well as on the interfaces their
+`listen` settings name, and trust `X-Forwarded-For` from it, which Caddy sets from the peer and
+never takes from the client.
+
+Consequences: HTTPS needs `wan.local_fqdn` in public DNS pointing at the router and port 80
+reachable from the internet; until then Caddy retries and the HTTPS ports do not answer. The
+certificate and the ACME account are in `/var/lib/caddy`. Plain HTTP stays as the `listen`
+settings set it, so `internal` keeps passwords off the internet. Caddy's admin endpoint listens
+on `localhost:2019`, which `caddy reload` uses. Port 80 and the HTTPS ports are not available
+to Docker containers while HTTPS is on. The Manager's HTTPS port is a setting of the router, not
+of the manager.
+
+## ADR-22: Metrics are kept in PostgreSQL and served in the Prometheus format, pushed with OTLP
+
+Status: Accepted
+
+Context: The router should keep its CPU, memory, disk, network, load and VPN client metrics for
+hour, day, month and year views, as Proxmox VE does, and expose them to OpenTelemetry. Ubuntu
+noble has no OpenTelemetry Python SDK and no OpenTelemetry Collector package. OTLP itself is
+push-only; a collector reads a scraped endpoint in the Prometheus format with its `prometheus`
+receiver. The router already runs PostgreSQL for the refresh tokens (ADR-15).
+
+Decision: A service of its own, `vpn-router-metrics`, takes a sample every minute with `psutil`
+(`python3-psutil`) and the VPN readers it shares with the web service (`vpnrouter_status`). It
+keeps the samples in the router's database, in three detail tables (`metrics_system`,
+`metrics_network`, `metrics_vpn`). Each detail table has hourly, daily, monthly and yearly summary
+tables, with the average and the maximum of each value per period, written when the clock passes a
+period from the level below with `INSERT ... ON CONFLICT DO NOTHING`, so a stopped service catches
+up. Garbage collection runs on start and once a day, not with every write, and deletes the rows
+older than the retention of their level, `metrics.keep_*`, PostgreSQL intervals. The service serves
+the last sample as `/metrics` in the Prometheus text format with `prometheus_client`
+(`python3-prometheus-client`) and pushes it as OTLP/HTTP JSON, built with the standard library, to
+`metrics.otlp_endpoint`. The names follow the OpenTelemetry semantic conventions. The web service
+answers the views from the tables at `/metrics/history`, protected like `/config`, for the Router
+Manager.
+
+Consequences: The metrics live in the database of the refresh tokens and are dropped with it on
+purge. A view shows only what its level keeps, so a shorter retention empties the older part of a
+view. A month view needs the hourly rows and a year view the monthly rows. `/metrics` has only the
+last sample; history is not scraped.
+
+## ADR-23: /metrics takes HTTP Basic authentication of a service account that setup owns
+
+Status: Accepted
+
+Context: An OpenTelemetry Collector's `prometheus` receiver authenticates with HTTP Basic, not with
+the router's tokens, which last minutes (ADR-3). The scraper should not be able to sign in to the
+API or the Manager, and its password should be checked and locked out like any other. The account
+belongs to the package's metrics, not to the people using the router.
+
+Decision: A service account is a Manager-only account (ADR-18) with `vpnRouterScope` `service`.
+`vpn-router-setup` owns it: while metrics are enabled it adds the account `metrics.service_account`
+names, `metrics` by default, with a random password it writes to `/etc/vpn-router/metrics.secret`
+(root only), and sets a new random password, ending a lockout, when the file is missing or no
+longer holds the password. `vpn-router-user` and `/users` cannot add one. `/auth` refuses it
+with the message of a wrong password. `/metrics` accepts HTTP Basic only for that account, and
+only when it is a service account; the password is checked with a bind as the account, so the
+password policy's lockout applies (ADR-14). TLS is Caddy's, on `metrics.https_port` (ADR-21);
+plain HTTP is served on the interfaces `metrics.listen` names, `internal` by default.
+
+Consequences: Every scrape binds to slapd once. The collector's operator copies the password from
+the router; deleting the file and running setup changes it. A user who already has the name is not
+taken over; setup fails until `metrics.service_account` names another. A disabled account stays
+disabled. A scraper on the external interface over plain HTTP sends the password in the clear, so
+`metrics.listen` stays `internal` unless HTTPS is used.
@@ -9,6 +9,8 @@ A Debian package that configures a Linux host or virtual machine as a VPN router
 - optional WireGuard endpoint
 - routing and NAT for a protected subnet, TCP MSS clamping, and UFW firewall rules
 - firewall rules for the ports Docker publishes, when Docker is installed
+- metrics of the router kept in PostgreSQL, served for an OpenTelemetry Collector and pushed
+  over OTLP

 Nothing in the package is specific to a cloud provider. It is built on the external and
 internal NIC names, and a `mode` setting says how much of the rest you are supplying and
@@ -123,10 +125,29 @@ must have the type shown below; an unknown section or setting is an error.
 | `openvpn` | `protocol` | string | `udp` | `udp` or `tcp` |
 | `docker` | `mode` | string | `auto` | `auto` secures Docker when its service is installed, `on` requires it, `off` removes the rules |
 | `docker` | `exposed_ports` | list | | TCP ports and port ranges (`8000:8100`) reachable from the external interface; at most 15, a range counting as two |
-| `web` | `enabled` | boolean | `true` | The status web service on the internal address |
+| `web` | `enabled` | boolean | `true` | The status web service |
+| `web` | `listen` | string | `both` | The interfaces the status web service listens on: `internal`, `external` or `both` |
 | `web` | `port` | integer | `7081` | TCP port of the status web service |
 | `web` | `database` | string | | A PostgreSQL connection string for the refresh tokens; without it, the `vpn-router` database on this host that the web service creates |
-| `web` | `trusted_proxies` | list | the listening address | Addresses whose `X-Forwarded-For` header names the client for the `/auth` rate limit |
+| `web` | `trusted_proxies` | list | the address the call came in on | Addresses whose `X-Forwarded-For` header names the client for the `/auth` rate limit and the Client IP of the status |
+| `web` | `status_content` | string | `basic` | What `/` and `/status` show: `basic`, `standard` or `full` (see Status web service) |
+| `https` | `enabled` | boolean | `true` | Caddy serves the status web service and the Router Manager over HTTPS for `wan.local_fqdn` |
+| `https` | `email` | string | | The e-mail address of the Let's Encrypt account |
+| `https` | `web_port` | integer | `7444` | HTTPS port of the status web service |
+| `https` | `manager_port` | integer | `7443` | HTTPS port of the Router Manager |
+| `metrics` | `enabled` | boolean | `true` | The metrics service: collection, history and `/metrics` |
+| `metrics` | `listen` | string | `internal` | The interfaces `/metrics` is served on: `internal`, `external` or `both` |
+| `metrics` | `port` | integer | `9464` | TCP port of `/metrics` |
+| `metrics` | `https_port` | integer | `9465` | HTTPS port of `/metrics`, served by Caddy while `https.enabled` is true |
+| `metrics` | `service_account` | string | `metrics` | The service account `/metrics` takes, which `vpn-router-setup` adds and keeps |
+| `metrics` | `otlp_endpoint` | string | | An OTLP/HTTP URL the metrics are pushed to every minute, for example `https://collector.example.com:4318/v1/metrics` |
+| `metrics` | `otlp_username` | string | | The user name of HTTP Basic authentication at the OTLP endpoint |
+| `metrics` | `otlp_password` | string | | Its password |
+| `metrics` | `keep_details` | string | `24 hours` | How long the per-minute metrics are kept |
+| `metrics` | `keep_hourly` | string | `1 month` | How long the hourly summaries are kept |
+| `metrics` | `keep_daily` | string | `3 months` | How long the daily summaries are kept |
+| `metrics` | `keep_monthly` | string | `1 year` | How long the monthly summaries are kept |
+| `metrics` | `keep_yearly` | string | `10 years` | How long the yearly summaries are kept |

 A minimal site-to-site configuration in `auto` mode:

@@ -234,6 +255,24 @@ vpn-router-setup` applies a changed configuration while Docker runs. With `docke
 `on`, the service fails when Docker is not installed or its daemon is not running; with
 `off` it removes the rules.

+## Editing the configuration
+
+`vpn-config-edit`, run as root, shows and changes `/etc/vpn-router/vpn-router.json`:
+
+```sh
+vpn-config-edit show
+vpn-config-edit set web.status_content standard
+vpn-config-edit set web.port 7082
+vpn-config-edit set web.trusted_proxies 127.0.0.1,10.0.0.4
+```
+
+`show` prints the file as indented JSON and does not change it. `set` takes a setting as
+`section.option` and converts the value to the setting's type: a whole number, `true` or
+`false`, a list separated by commas (an empty value is an empty list), or a string; an unknown
+setting is refused. It checks the whole configuration as `vpn-router-setup` does, and only then
+writes the file, indented, with mode 0600, and reminds that `vpn-router-setup` applies it. A
+refused request exits with status 2, any other failure with 1.
+
 ## Applying changes

 ```sh
@@ -328,8 +367,9 @@ is switched on:
  `account` for a Manager-only account (see Managing users);
 - the package's own schema, `cn=vpn-router,cn=schema,cn=config`, under the OID
  `2.25.98477352595735834532404256531620013001` of the UUID arc: the auxiliary class
-  `vpnRouterAccount` with `MAY ( mail $ vpnRouterScope )`, which Manager-only accounts have, and
-  the attribute `vpnRouterScope`, authorization scopes that nothing reads yet;
+  `vpnRouterAccount` with `MAY ( mail $ vpnRouterScope )`, which Manager-only and service accounts
+  have, and the attribute `vpnRouterScope`, authorization scopes, of which `service` marks a
+  service account;
 - `ou=groups` holds one `groupOfNames` per group, named by `cn`, with its members' DNs in
  `member` and an optional `description`;
 - `cn=user-manager,ou=services` is the account that changes users and groups; it may write
@@ -351,8 +391,8 @@ The directory is kept on purge.

 ### Managing users

-`vpn-router-user` manages the users. A user is a directory entry of one of two kinds, fixed when it
-is added:
+`vpn-router-user` manages the users. A user is a directory entry of one of three kinds, fixed when
+it is added:

 - a VPN user, an `inetOrgPerson` with a first name, a last name and an e-mail address
  (`givenName`, `sn` and `mail`; `cn` is the first and the last name), and a client certificate
@@ -360,7 +400,10 @@ is added:
 - a Manager-only account, an `account`, `simpleSecurityObject` and `vpnRouterAccount` with the
  name, the password and an optional e-mail address, for notifications: no names and no
  certificate, so no VPN access. It can sign in to `/auth` and, as a member of `admins`, manage
-  the router. `add` without the first and the last name adds one; its names cannot be set later.
+  the router. `add` without the first and the last name adds one; its names cannot be set later;
+- a service account, a Manager-only account whose `vpnRouterScope` is `service`, which
+  `vpn-router-setup` adds and keeps for the metrics service (see Metrics); it cannot sign in to
+  `/auth`, and `vpn-router-user` and `/users` cannot add one.

 Passwords and TOTP secrets are read from the first line of standard input. The answer is text: a
 table of the users, the client profile, a TOTP secret or a short message, and a failure is a
@@ -492,9 +535,22 @@ modules shipped with the package; the configuration file accepts any module inst

 ## Status web service

-The `vpn-router-web` service shows the state of the router on its internal address and
-`web.port` (7081 by default). Its pages `/` and `/status` need no authentication and show no
-configuration: no key, identity, address or subnet.
+The `vpn-router-web` service shows the state of the router on the addresses of the interfaces
+`web.listen` names, the internal, the external or both (the default), and on `127.0.0.1`, where
+Caddy calls it (see HTTPS), with `web.port` (7081 by default). Its pages `/` and `/status` need no authentication and show no
+configuration: no key, identity, subnet, or address but the client's. They show as much as
+`web.status_content` says, read at each request:
+
+| `status_content` | `/` and `/status` show |
+|---|---|
+| `basic` (default) | The overall status (`ok` or `degraded`), the time and the Client IP |
+| `standard` | Also the `vpn-router` version, the `vpn-router-manager` version or that it is not installed, and the number of active services and of services in any other state, without their names |
+| `full` | Also each service and its state, Docker, and the state of site-to-site, road-warrior, OpenVPN and WireGuard |
+
+The Client IP is the address the request came from: the last entry of `X-Forwarded-For` for a
+request from one of `web.trusted_proxies`, by default the address the request came in on, so
+behind Caddy or a Router Manager on the router it is the browser's. `/status` names the content in
+`content` and the Client IP in `client_ip`; `/` keeps the time and the link to `/status`.

 The service first makes its signing key and the refresh tokens' database, retrying every 15
 seconds, for example while PostgreSQL is not running yet, and logs each failure; then it listens.
@@ -585,7 +641,7 @@ removed. Changing a user's password, disabling, unlocking or removing the user r
 user's refresh tokens. Five failed logins lock the account for 15 minutes (see the user
 directory). `/auth` and `/auth/refresh` take at most 10 calls a minute from one client address,
 and answer 429 with `Retry-After` beyond that; for a call from one of `web.trusted_proxies`, by
-default the address the service listens on, the client address is the last entry of
+default the address the call came in on, the client address is the last entry of
 `X-Forwarded-For`.

 Refresh tokens are kept, as their SHA-256, in PostgreSQL: by default in the database and role
@@ -680,13 +736,127 @@ otherwise. `DELETE /users/<name>` is refused with 400 while the user is the last
 group.

 The service starts on its own, without waiting for `vpn-router-setup`, and keeps running. Every
-30 seconds it works out the internal address from `vpn-router.json` as `general.mode` directs,
-and reads `web.port` and `web.enabled`; it listens there, moves when the address or the port
-changes, and stops listening while `web.enabled` is `false` or the address is not known. Each
-request reads the signing key and `vpn-router.json`, and the features and the facts for
-`/config` from `/run/vpn-router/web.json` (readable by root only), which `vpn-router-setup` writes;
-before that file exists the page shows no features. `vpn-router-setup` opens `web.port` on the
-internal interface in the firewall.
+30 seconds it reads `web.listen`, `web.port` and `web.enabled` from `vpn-router.json` and works
+out the addresses of the interfaces `web.listen` names as `general.mode` directs; it listens on
+each, moves when an address or the port changes, and stops listening while `web.enabled` is
+`false` or no address is known. A change of `web.listen` takes effect within 30 seconds, or when
+the service restarts. Each request reads the signing key and `vpn-router.json`, and the features
+and the facts for `/config` from `/run/vpn-router/web.json` (readable by root only), which
+`vpn-router-setup` writes; before that file exists the page shows no features.
+`vpn-router-setup` opens `web.port` on the internal and the external interface in the firewall.
+
+## HTTPS
+
+Caddy, from Ubuntu's `caddy` package, serves the status web service on `https.web_port` (7444 by
+default), while the Router Manager is installed the manager on `https.manager_port` (7443), and
+while metrics are enabled the metrics service on `metrics.https_port` (9465), all for `wan.local_fqdn`, while `https.enabled` is `true` and `wan.local_fqdn` is set. It obtains
+and renews the certificate from Let's Encrypt with the HTTP challenge, so `wan.local_fqdn` must
+resolve to the router's public address and port 80 must be reachable from the internet; the
+certificate and the ACME account are kept in `/var/lib/caddy`. Port 80 answers the challenge only;
+it does not redirect to HTTPS.
+
+`vpn-router-setup` writes Caddy's configuration to `/etc/caddy/vpn-router.Caddyfile` (root, group
+`caddy`, the group Caddy runs as, mode 0640), which the
+package's drop-in `/usr/lib/systemd/system/caddy.service.d/vpn-router.conf` makes `caddy.service`
+read; `caddy.service` does not start before the file exists, and `/etc/caddy/Caddyfile` is not
+used. Setup starts Caddy, reloads it when the file changes, and stops it and removes the file when
+HTTPS is off. In the firewall it opens port 80 on the external interface and the HTTPS ports on the
+internal and the external interface. Caddy calls both services on `127.0.0.1`, where they listen
+whatever `web.listen` and the manager's `listen` say, and passes the client's address in
+`X-Forwarded-For`, which the manager trusts from `127.0.0.1` and the web service by default, as
+the address the call came in on; a `web.trusted_proxies` that is set must list `127.0.0.1`. The plain HTTP ports stay as
+`web.listen` and the manager's `listen` set them. `docker.exposed_ports` may not take port 80 or
+the HTTPS ports while `https.enabled` is `true`.
+
+```bash
+curl https://router.example.com:7444/status
+```
+
+## Metrics
+
+While `metrics.enabled` is `true`, `vpn-router-setup` runs `vpn-router-metrics`, which every minute
+takes a sample of the router with `psutil`:
+
+- the CPU utilization;
+- the memory used and in total;
+- the free and the total space of `/`;
+- the bytes received and sent per second on the external and the internal interface;
+- the 1, 5 and 15 minute load averages;
+- the VPN clients of each enabled VPN system: road-warrior (IPsec P2S) and OpenVPN clients,
+  WireGuard peers with a handshake in the last 3 minutes, and the site-to-site tunnel, 1 while it is
+  up.
+
+### History
+
+The samples are kept in the router's PostgreSQL database, the one of the refresh tokens
+(`web.database`), in three detail tables, one row per minute, and each is summarized hourly, daily,
+monthly and yearly. A summary row has the start of its period, in UTC, and the average and the
+maximum of each value:
+
+| Level | Tables | Kept |
+|---|---|---|
+| Details | `metrics_system`, `metrics_network`, `metrics_vpn` | `metrics.keep_details` |
+| Hourly | `metrics_system_hourly`, `metrics_network_hourly`, `metrics_vpn_hourly` | `metrics.keep_hourly` |
+| Daily | `metrics_system_daily`, `metrics_network_daily`, `metrics_vpn_daily` | `metrics.keep_daily` |
+| Monthly | `metrics_system_monthly`, `metrics_network_monthly`, `metrics_vpn_monthly` | `metrics.keep_monthly` |
+| Yearly | `metrics_system_yearly`, `metrics_network_yearly`, `metrics_vpn_yearly` | `metrics.keep_yearly` |
+
+How it works:
+
+- **Summaries:** a period is summarized once it is complete, from the level below. A stopped service catches up on the periods it missed, as long as their rows are still kept.
+- **Garbage collection:** runs on start and once a day. It deletes the rows older than their retention, a count and a unit such as `24 hours`, `3 months` or `10 years`.
+- **History API:** `GET /metrics/history?range=hour|day|month|year` of the status web service, protected like `/config`, answers the views of the Router Manager's Metrics tab:
+
+  | Range | Bucket | Source |
+  |---|---|---|
+  | `hour` | 1 minute | details |
+  | `day` | 10 minutes | details |
+  | `month` | 6 hours | hourly |
+  | `year` | 1 month | monthly |
+
+### Scraping
+
+`GET /metrics` of the metrics service serves the last sample in the Prometheus text format, written by `prometheus_client`.
+
+- **Metric names:** the OpenTelemetry semantic convention names in their Prometheus form:
+  - `system_cpu_utilization`;
+  - `system_memory_usage_bytes` and `system_memory_limit_bytes`;
+  - `system_filesystem_usage_bytes` and `system_filesystem_utilization`;
+  - `system_network_io_bytes_total`;
+  - `system_cpu_load_average_1m`, `_5m` and `_15m`;
+  - `vpn_router_clients`.
+- **Listening:** on the interfaces `metrics.listen` names, `internal` by default, at `metrics.port`, and on `127.0.0.1`. While HTTPS is on, Caddy serves it at `metrics.https_port` for `wan.local_fqdn`. `vpn-router-setup` opens both ports on the internal and the external interface.
+- **Authentication:** HTTP Basic as the service account `metrics.service_account` names, `metrics` by default. The password is checked with a bind to the user directory, so 5 failed attempts lock the account as for any user.
+- **The account:** `vpn-router-setup` owns it while metrics are enabled.
+  - It adds the account with a random password, which it writes to `/etc/vpn-router/metrics.secret` (root only). Give that password to the collector.
+  - When the file is missing or no longer holds the account's password, setup sets a new random password and ends any lockout. Delete the file and restart `vpn-router-setup` to change the password.
+  - A disabled account is left as it is.
+  - A user of that name who is not a service account is a setup failure.
+
+An OpenTelemetry Collector scrapes it with its `prometheus` receiver:
+
+```yaml
+receivers:
+  prometheus:
+    config:
+      scrape_configs:
+        - job_name: vpn-router
+          scrape_interval: 60s
+          scheme: https
+          basic_auth:
+            username: metrics
+            password_file: /etc/otelcol/vpn-router-metrics.secret   # a copy of /etc/vpn-router/metrics.secret
+          static_configs:
+            - targets: ['router.example.com:9465']
+```
+
+### Pushing
+
+When `metrics.otlp_endpoint` is set, every sample is also pushed there as an OTLP/HTTP JSON request.
+
+- **Content:** the semantic convention names (`system.cpu.utilization`, `system.network.io` and so on), and the resource attributes `service.name` `vpn-router` and `host.name`.
+- **Authentication:** HTTP Basic with `metrics.otlp_username` and `metrics.otlp_password` when they are set.
+- **Failures:** a failed push is logged and not repeated; the next sample is pushed a minute later.

 ## Router Manager

@@ -694,21 +864,25 @@ The `vpn-router-manager` package, built in the repository `linux-cloud-router-ma
 application that shows the state of the router and manages its users through the status web
 service. It can be installed on the router or on another Linux system. While it is installed on
 the router, `vpn-router-setup` opens its port (`port` in `/etc/vpn-router-manager/manager.json`,
-7080 by default, HTTP; 7443 is kept for it with TLS) on the internal interface; restart
-`vpn-router-setup` after changing it.
+7080 by default, HTTP; HTTPS is Caddy's, on `https.manager_port`) on the internal and the external
+interface; restart `vpn-router-setup` after changing it. The manager's `listen` chooses the
+interfaces it listens on.

 ## Removal

 `apt-get remove` stops `vpn-router-docker`, which removes the Docker rules. It terminates the
-tunnels and takes `wg-quick@wg0` and `openvpn-server@vpn-router` down, but leaves the
+tunnels and takes `wg-quick@wg0`, `openvpn-server@vpn-router`, `caddy` and `vpn-router-metrics`
+down, but leaves the
 configuration in place. `strongswan` is left enabled, since it is a shared service that
 may be in use by something else.

 `apt-get purge` additionally removes the generated files and the firewall rules, restoring
 `/etc/ufw/before.rules` to its original content, and hands `vpn-router.json` back to `ucf`
 before deleting it so a later reinstall starts clean. It also removes the web service's
-signing key, and the refresh tokens' database, its role and their password file when the package
-created them. Key material and users are never deleted: `/etc/vpn-router/pki`, `/etc/vpn-router/ldap`, the user directory in slapd, the
+signing key, the password file of the metrics service account, and the database of the refresh
+tokens and the metrics, its role and their password
+file when the package created them, and Caddy's configuration `/etc/caddy/vpn-router.Caddyfile`; the certificate in
+`/var/lib/caddy` belongs to the `caddy` package. Key material and users are never deleted: `/etc/vpn-router/pki`, `/etc/vpn-router/ldap`, the user directory in slapd, the
 WireGuard key pair and everything under `/etc/swanctl` are left alone.

 ## Building
@@ -1,3 +1,106 @@
+vpn-router (0.16.0-1) unstable; urgency=medium
+
+  feature: the router keeps its metrics in PostgreSQL, serves them for an OpenTelemetry Collector and pushes them over OTLP.
+
+  * vpn-router-metrics takes a sample every minute: CPU, memory, free
+    space of /, bytes per second on the external and the internal
+    interface, the load averages, and the VPN clients of each enabled
+    system.
+  * The samples are kept in metrics_system, metrics_network and
+    metrics_vpn, and summarized hourly, daily, monthly and yearly in
+    their _hourly, _daily, _monthly and _yearly tables; once a day the
+    rows older than metrics.keep_details, keep_hourly, keep_daily,
+    keep_monthly and keep_yearly are deleted.
+  * /metrics serves the last sample in the Prometheus format on the
+    interfaces metrics.listen names (internal by default) at
+    metrics.port, and over HTTPS by Caddy at metrics.https_port, with
+    HTTP Basic authentication of the service account
+    metrics.service_account names (metrics by default).
+  * metrics.otlp_endpoint pushes every sample as OTLP/HTTP JSON, with
+    metrics.otlp_username and metrics.otlp_password.
+  * /metrics/history of the web service answers the hour, day, month
+    and year views for the Router Manager.
+  * vpn-router-setup adds and keeps that service account, which cannot
+    sign in to /auth, with a random password in
+    /etc/vpn-router/metrics.secret, set anew when the file is missing.
+  * Depends on python3-psutil and python3-prometheus-client.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 19:00:00 +0200
+
+vpn-router (0.15.0-1) unstable; urgency=medium
+
+  feature: vpn-config-edit shows and changes the router's configuration.
+
+  * vpn-config-edit show prints /etc/vpn-router/vpn-router.json as
+    indented JSON.
+  * vpn-config-edit set SECTION.OPTION VALUE converts the value to the
+    setting's type, checks the whole configuration as vpn-router-setup
+    does, writes the file indented with mode 0600, and reminds that
+    vpn-router-setup applies it.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 18:00:00 +0200
+
+vpn-router (0.14.1-1) unstable; urgency=medium
+
+  fix: web.status_content is basic by default.
+
+  * Without web.status_content, or with a value that is not allowed, /
+    and /status show only the overall status, the time and the Client
+    IP; set it to standard or full to show more.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 17:00:00 +0200
+
+vpn-router (0.14.0-1) unstable; urgency=medium
+
+  feature: the status page shows the Client IP, and web.status_content sets how much it shows.
+
+  * / and /status show the Client IP, the address the request came from:
+    the last X-Forwarded-For entry for a request from a trusted proxy, so
+    behind Caddy or the Router Manager the browser's; /status has it as
+    client_ip.
+  * web.status_content sets what / and /status show: basic the overall
+    status, the time and the Client IP; standard also the package
+    versions and the number of active and failed services; full, the
+    default, everything as before. /status names it in content.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 16:00:00 +0200
+
+vpn-router (0.13.0-1) unstable; urgency=medium
+
+  feature: Caddy serves the status page and the Router Manager over HTTPS with a certificate from Let's Encrypt.
+
+  * The package depends on caddy. While https.enabled is true, the
+    default, and wan.local_fqdn is set, vpn-router-setup writes
+    /etc/caddy/vpn-router.Caddyfile and runs Caddy, which serves the
+    status page on https.web_port (7444) and the Router Manager, when it
+    is installed, on https.manager_port (7443) for wan.local_fqdn, and
+    obtains the certificate from Let's Encrypt with the HTTP challenge.
+  * The package's drop-in for caddy.service makes Caddy read that file
+    and keeps it from starting before the file exists. The file belongs
+    to root and the group caddy, which Caddy runs as, with mode 0640.
+  * The firewall opens port 80 on the external interface and the HTTPS
+    ports on both interfaces while HTTPS is on.
+  * The web service also listens on 127.0.0.1, where Caddy calls it.
+  * docker.exposed_ports may not take port 80 or the HTTPS ports while
+    HTTPS is on.
+  * Removing the package stops and disables caddy; purging it removes
+    /etc/caddy/vpn-router.Caddyfile.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 15:00:00 +0200
+
+vpn-router (0.12.3-1) unstable; urgency=medium
+
+  fix: the web service listens on the internal address, the external address or both.
+
+  * web.listen in vpn-router.json sets the interfaces the web service
+    listens on: internal, external or both, the default. It is read
+    every 30 seconds, so a change takes effect without running setup,
+    at the latest when vpn-router-web restarts.
+  * The firewall opens the ports of the web service and of the Router
+    Manager on the internal and the external interface.
+
+ -- Slawomir Koszewski <slawek@koszewscy.waw.pl>  Sun, 25 Oct 2026 13:00:00 +0200
+
 vpn-router (0.12.2-1) unstable; urgency=medium

  fix: the web service manages users also when it started before setup.
@@ -23,19 +23,23 @@ Depends: ${misc:Depends},
         python3-ldap,
         python3-pyotp,
         python3-psycopg,
+         python3-psutil,
+         python3-prometheus-client,
         postgresql,
         slapd,
         openvpn,
         openvpn-auth-ldap,
         iproute2,
-         systemd-resolved
+         systemd-resolved,
+         caddy
 Description: Linux VPN router with IPSec, road-warrior, OpenVPN and WireGuard support
 Configures a Linux host or virtual machine as a VPN router: site-to-site
 IKEv2 IPSec (strongSwan swanctl), optional road-warrior access using EAP-TLS,
 optional OpenVPN with a certificate and a password per user, kept in a local
 LDAP directory, optional WireGuard, and the routing, NAT, MSS clamping and
- firewall rules a router needs. Nothing in the package is specific to a cloud
- provider.
+ firewall rules a router needs. It keeps metrics of the router in PostgreSQL
+ and serves them for an OpenTelemetry Collector. Nothing in the package is
+ specific to a cloud provider.
 .
 Settings live in /etc/vpn-router/vpn-router.json, which is created on first
 install and owned by the administrator afterwards. Editing it and restarting
@@ -5,18 +5,23 @@ src/usr/lib/vpn-router/vpnrouter_net.py               usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_serve.py             usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_users.py             usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_auth.py              usr/lib/vpn-router/
+src/usr/lib/vpn-router/vpnrouter_metrics.py           usr/lib/vpn-router/
+src/usr/lib/vpn-router/vpnrouter_status.py            usr/lib/vpn-router/
 src/usr/lib/vpn-router/openvpn-same-user              usr/lib/vpn-router/
 src/usr/sbin/vpn-router-user                          usr/sbin/
 src/usr/sbin/vpn-router-group                         usr/sbin/
 src/usr/sbin/vpn-router-token                         usr/sbin/
+src/usr/sbin/vpn-config-edit                          usr/sbin/
 src/usr/lib/vpn-router/simple-ca                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/configure                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/docker-rules                   usr/lib/vpn-router/
 src/usr/lib/vpn-router/setup                          usr/lib/vpn-router/
 src/usr/lib/vpn-router/web                            usr/lib/vpn-router/
+src/usr/lib/vpn-router/metrics                        usr/lib/vpn-router/
 src/usr/lib/vpn-router/bootstrap                      usr/lib/vpn-router/
 src/usr/lib/vpn-router/wait-for-libpq                 usr/lib/vpn-router/
 src/usr/lib/vpn-router/generate-config                usr/lib/vpn-router/
 src/usr/lib/vpn-router/vpnrouter_platforms/*.py       usr/lib/vpn-router/vpnrouter_platforms/
 src/usr/share/vpn-router/templates/*                  usr/share/vpn-router/templates/
+src/usr/lib/systemd/system/caddy.service.d/vpn-router.conf usr/lib/systemd/system/caddy.service.d/
 src/usr/share/doc/vpn-router/vpn-router.json.example  usr/share/doc/vpn-router/
@@ -11,10 +11,10 @@ strip_ufw_blocks() {

    tmp="$(mktemp)"
    awk '
-        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES START$/ {
+        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|HTTPS|METRICS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES START$/ {
            skip = 1; pending = 0; next
        }
-        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES END$/ {
+        /^# (IPSEC|WIREGUARD|OPENVPN|P2S DNS|WEB|BOOTSTRAP|MANAGER|HTTPS|METRICS|ROUTER FORWARD|ROUTER NAT|ROUTER MSS) RULES END$/ {
            skip = 0; next
        }
        skip { next }
@@ -49,8 +49,10 @@ case "$1" in
              /etc/wireguard/wg0.conf \
              /etc/openvpn/server/vpn-router.conf \
              /etc/openvpn/server/vpn-router-ldap.conf \
+              /etc/caddy/vpn-router.Caddyfile \
              /etc/vpn-router/vpn-router.json \
              /etc/vpn-router/web.key \
+              /etc/vpn-router/metrics.secret \
              /var/lib/vpn-router/setup.done
        rmdir --ignore-fail-on-non-empty /var/lib/vpn-router 2>/dev/null || true

@@ -11,10 +11,11 @@ case "$1" in
            swanctl --terminate --ike road-warrior >/dev/null 2>&1 || true
        fi

-        # This package enabled wg-quick@wg0 and openvpn-server@vpn-router, so
-        # it takes them down again. Use the debhelper wrappers rather than
-        # systemctl, so the script behaves on a machine without systemd.
-        for unit in wg-quick@wg0.service openvpn-server@vpn-router.service; do
+        # vpn-router-setup enabled wg-quick@wg0, openvpn-server@vpn-router,
+        # caddy and vpn-router-metrics, so the package takes them down again.
+        # Use the debhelper wrappers rather than systemctl, so the script
+        # behaves on a machine without systemd.
+        for unit in wg-quick@wg0.service openvpn-server@vpn-router.service caddy.service vpn-router-metrics.service; do
            if command -v deb-systemd-invoke >/dev/null 2>&1; then
                deb-systemd-invoke stop "$unit" >/dev/null 2>&1 || true
            fi
@@ -6,4 +6,5 @@ override_dh_installsystemd:
 	dh_installsystemd --name=vpn-router-setup
 	dh_installsystemd --name=vpn-router-docker
 	dh_installsystemd --name=vpn-router-web --no-start
+	dh_installsystemd --name=vpn-router-metrics --no-enable --no-start
 	dh_installsystemd --name=vpn-router-bootstrap --no-enable --no-start
@@ -0,0 +1,22 @@
+[Unit]
+Description=VPN Router metrics service
+Documentation=file:/usr/share/doc/vpn-router/README.md
+After=network-online.target postgresql.service vpn-router-web.service
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStartPre=/usr/lib/vpn-router/wait-for-libpq
+ExecStart=/usr/bin/python3 /usr/lib/vpn-router/metrics
+TimeoutStartSec=5min
+Restart=on-failure
+RestartSec=15
+NoNewPrivileges=yes
+ProtectSystem=strict
+RuntimeDirectory=vpn-router
+RuntimeDirectoryPreserve=yes
+ProtectHome=yes
+PrivateTmp=yes
+
+[Install]
+WantedBy=multi-user.target
@@ -0,0 +1,10 @@
+# Caddy is the HTTPS proxy of vpn-router: it reads the configuration vpn-router-setup writes, and
+# does not start until that exists.
+[Unit]
+ConditionPathExists=/etc/caddy/vpn-router.Caddyfile
+
+[Service]
+ExecStart=
+ExecStart=/usr/bin/caddy run --environ --adapter caddyfile --config /etc/caddy/vpn-router.Caddyfile
+ExecReload=
+ExecReload=/usr/bin/caddy reload --adapter caddyfile --config /etc/caddy/vpn-router.Caddyfile --force
@@ -0,0 +1,414 @@
+#!/usr/bin/python3
+"""Collect the metrics of the router, keep them in PostgreSQL, serve them for scraping and push them with OTLP.
+
+Run by vpn-router-metrics.service while metrics.enabled is true; vpn-router-setup enables and
+disables the unit.
+
+Every SAMPLE_SECONDS, on the minute, a sample is taken with psutil: the CPU utilization since the
+previous sample, the memory used and in total, the free and the total space of /, the bytes
+received and sent per second on the external and the internal interface, and the load averages;
+and the VPN clients of each enabled VPN system (vpnrouter_status): road-warrior (p2s) and
+OpenVPN clients, WireGuard peers with a recent handshake, and the site-to-site tunnel, 1 while it
+is up. The interfaces and the enabled systems are those vpn-router-setup resolved, read from
+/run/vpn-router/web.json.
+
+The sample is written to the detail tables of vpnrouter_metrics. When the clock has passed into
+a new hour, day, month or year, the complete periods are summarized, and once a day, after the
+daily summary, the rows older than their retention are deleted; both also run on start. A
+failure of the database is logged and tried again with the next sample.
+
+GET /metrics answers the last sample in the Prometheus text format, written by
+prometheus_client, with OpenTelemetry semantic convention names in their Prometheus form, for an
+OpenTelemetry Collector's prometheus receiver. It needs HTTP Basic authentication as the service
+account metrics.service_account names, which vpn-router-setup keeps with the password in
+/etc/vpn-router/metrics.secret, checked with a bind to the router's directory, so failed attempts
+lock the account as for any user. The service listens on the interfaces metrics.listen
+names and on the loopback address, where Caddy serves it over HTTPS at metrics.https_port; the
+address of a call through Caddy is the last entry of its X-Forwarded-For header.
+
+When metrics.otlp_endpoint is set, every sample is also pushed there as an OTLP/HTTP JSON
+ExportMetricsServiceRequest, with HTTP Basic authentication when metrics.otlp_username is set.
+"""
+
+import base64
+import datetime
+import json
+import os
+import signal
+import socket
+import sys
+import threading
+import time
+import urllib.error
+import urllib.request
+from http.server import BaseHTTPRequestHandler
+
+sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
+
+import ldap
+import psutil
+from prometheus_client import CONTENT_TYPE_LATEST, generate_latest
+from prometheus_client.core import CollectorRegistry, CounterMetricFamily, GaugeMetricFamily
+
+import vpnrouter
+import vpnrouter_metrics
+import vpnrouter_net
+import vpnrouter_serve
+import vpnrouter_status
+import vpnrouter_users
+
+STATE_FILE = '/run/vpn-router/web.json'
+CONFIG_FILE = '/etc/vpn-router/vpn-router.json'
+
+SAMPLE_SECONDS = 60
+
+#: Seconds between two discoveries of where the service should listen.
+DISCOVERY_SECONDS = 30
+
+#: Seconds an OTLP push may take.
+OTLP_TIMEOUT = 10
+
+#: The mount point whose space is measured.
+MOUNTPOINT = '/'
+
+#: The last sample, as sample() makes it, or None before the first.
+_latest = {'sample': None}
+_latest_lock = threading.Lock()
+
+
+def log(message):
+    print(f'vpn-router-metrics: {message}', file=sys.stderr, flush=True)
+
+
+def read_json(path):
+    """The object in a JSON file, or {} when the file is missing or holds no object."""
+    try:
+        with open(path, encoding='utf-8') as handle:
+            data = json.load(handle)
+    except (OSError, ValueError):
+        return {}
+    return data if isinstance(data, dict) else {}
+
+
+def section(configuration, name):
+    """A section of the configuration, or {} when it is missing or not an object."""
+    value = configuration.get(name)
+    return value if isinstance(value, dict) else {}
+
+
+def clients(state):
+    """The VPN clients of each enabled VPN system, None where it cannot be asked."""
+    counts = {}
+    if state.get('p2s'):
+        counts['p2s'] = vpnrouter_status.established('road-warrior')
+    if state.get('openvpn'):
+        counts['openvpn'] = vpnrouter_status.openvpn_clients()
+    if state.get('wireguard'):
+        counts['wireguard'] = vpnrouter_status.wireguard_connected()
+    if state.get('site_to_site'):
+        count = vpnrouter_status.established('remote-site')
+        counts['site_to_site'] = None if count is None else int(count > 0)
+    return counts
+
+
+def sample(previous):
+    """A sample of the router, with the rates since the previous sample, None for the first."""
+    state = read_json(STATE_FILE)
+    network = section(state, 'network')
+    names = [name for name in dict.fromkeys((network.get('external_interface'), network.get('internal_interface')))
+             if isinstance(name, str) and name]
+    counters = psutil.net_io_counters(pernic=True)
+    memory = psutil.virtual_memory()
+    disk = psutil.disk_usage(MOUNTPOINT)
+    load1, load5, load15 = os.getloadavg()
+    now = time.time()
+    current = {
+        'time': now,
+        'monotonic': time.monotonic(),
+        'system': {
+            'cpu': psutil.cpu_percent(interval=None),
+            'memory_used': memory.total - memory.available,
+            'memory_total': memory.total,
+            'disk_free': disk.free,
+            'disk_total': disk.total,
+            'load1': load1,
+            'load5': load5,
+            'load15': load15,
+        },
+        'counters': {name: (counters[name].bytes_recv, counters[name].bytes_sent) for name in names if name in counters},
+        'clients': clients(state),
+        'rates': {},
+    }
+    if previous is not None:
+        elapsed = current['monotonic'] - previous['monotonic']
+        for name, (received, sent) in current['counters'].items():
+            if name in previous['counters'] and elapsed > 0:
+                before_received, before_sent = previous['counters'][name]
+                current['rates'][name] = (max(received - before_received, 0) / elapsed, max(sent - before_sent, 0) / elapsed)
+    return current
+
+
+def periods(moment):
+    """The hour, the day, the month and the year of a UTC moment, keyed by the levels of vpnrouter_metrics.LEVELS."""
+    return {'hourly': moment.strftime('%Y-%m-%dT%H'), 'daily': moment.strftime('%Y-%m-%d'),
+            'monthly': moment.strftime('%Y-%m'), 'yearly': moment.strftime('%Y')}
+
+
+def store(cfg, current, done):
+    """Write the sample, summarize the periods the clock has passed and collect the garbage once a day.
+
+    done holds the periods summarized so far, and garbage the day of the last garbage collection;
+    it is updated only for what succeeded.
+    """
+    now = periods(datetime.datetime.now(datetime.timezone.utc))
+    with vpnrouter_metrics.database(cfg) as connection:
+        vpnrouter_metrics.write(connection, current['system'], current['rates'], current['clients'])
+        for level, _, _ in vpnrouter_metrics.LEVELS:
+            if done.get(level) != now[level]:
+                vpnrouter_metrics.summarize(connection, level)
+                done[level] = now[level]
+        if done.get('garbage') != now['daily']:
+            vpnrouter_metrics.collect_garbage(connection, cfg)
+            done['garbage'] = now['daily']
+
+
+def attributes(**values):
+    """OTLP attributes of string values."""
+    return [{'key': key, 'value': {'stringValue': value}} for key, value in values.items()]
+
+
+def otlp_request(current, started):
+    """The OTLP/HTTP JSON ExportMetricsServiceRequest of a sample; started is when the counters were first read, in Unix seconds."""
+    stamp = str(int(current['time'] * 1e9))
+    start = str(int(started * 1e9))
+    system = current['system']
+
+    def gauge(name, unit, points):
+        return {'name': name, 'unit': unit, 'gauge': {'dataPoints': [
+            {'timeUnixNano': stamp, 'asDouble': float(value), 'attributes': attributes(**labels)}
+            for value, labels in points if value is not None]}}
+
+    metrics = [
+        gauge('system.cpu.utilization', '1', [(system['cpu'] / 100, {})]),
+        gauge('system.memory.usage', 'By', [(system['memory_used'], {'state': 'used'})]),
+        gauge('system.memory.limit', 'By', [(system['memory_total'], {})]),
+        gauge('system.filesystem.usage', 'By', [(system['disk_free'], {'mountpoint': MOUNTPOINT, 'state': 'free'}),
+                                               (system['disk_total'] - system['disk_free'], {'mountpoint': MOUNTPOINT, 'state': 'used'})]),
+        gauge('system.filesystem.utilization', '1',
+              [(1 - system['disk_free'] / system['disk_total'] if system['disk_total'] else None, {'mountpoint': MOUNTPOINT})]),
+        gauge('system.cpu.load_average.1m', '{thread}', [(system['load1'], {})]),
+        gauge('system.cpu.load_average.5m', '{thread}', [(system['load5'], {})]),
+        gauge('system.cpu.load_average.15m', '{thread}', [(system['load15'], {})]),
+        gauge('vpn_router.clients', '{client}', [(count, {'kind': kind}) for kind, count in current['clients'].items()]),
+        {'name': 'system.network.io', 'unit': 'By', 'sum': {
+            'aggregationTemporality': 2, 'isMonotonic': True, 'dataPoints': [
+                {'startTimeUnixNano': start, 'timeUnixNano': stamp, 'asInt': str(value),
+                 'attributes': attributes(device=name, direction=direction)}
+                for name, counters in current['counters'].items()
+                for value, direction in zip(counters, ('receive', 'transmit'))]}},
+    ]
+    return {'resourceMetrics': [{
+        'resource': {'attributes': attributes(**{'service.name': 'vpn-router', 'host.name': socket.gethostname()})},
+        'scopeMetrics': [{'scope': {'name': 'vpn-router-metrics'}, 'metrics': metrics}],
+    }]}
+
+
+def push(metrics, current, started):
+    """Push the sample to metrics.otlp_endpoint; raises OSError when the collector does not take it."""
+    request = urllib.request.Request(metrics['otlp_endpoint'], data=json.dumps(otlp_request(current, started)).encode(),
+                                     headers={'Content-Type': 'application/json'}, method='POST')
+    if metrics['otlp_username']:
+        credentials = f"{metrics['otlp_username']}:{metrics['otlp_password']}".encode()
+        request.add_header('Authorization', 'Basic ' + base64.b64encode(credentials).decode())
+    with urllib.request.urlopen(request, timeout=OTLP_TIMEOUT) as response:
+        response.read()
+
+
+def collector_loop():
+    """Take a sample on every minute, store it and push it; every new failure is logged once."""
+    previous, done, reported = None, {}, {}
+    started = time.time()
+    psutil.cpu_percent(interval=None)
+
+    def report(kind, message):
+        if message != reported.get(kind):
+            if message:
+                log(message)
+            elif reported.get(kind):
+                log(f'{kind} works again')
+            reported[kind] = message
+
+    while True:
+        time.sleep(SAMPLE_SECONDS - time.time() % SAMPLE_SECONDS)
+        try:
+            cfg = vpnrouter.load_config()
+        except SystemExit as exc:
+            report('configuration', str(exc.code))
+            continue
+        report('configuration', '')
+        current = sample(previous)
+        previous = current
+        with _latest_lock:
+            _latest['sample'] = current
+        try:
+            store(cfg, current, done)
+            report('database', '')
+        except vpnrouter_metrics.DatabaseError as exc:
+            report('database', str(exc))
+        metrics = cfg['metrics']
+        if metrics['otlp_endpoint']:
+            try:
+                push(metrics, current, started)
+                report('OTLP push', '')
+            except (OSError, ValueError) as exc:
+                report('OTLP push', f"pushing to {metrics['otlp_endpoint']} failed: {exc}")
+
+
+class Sample:
+    """A prometheus_client collector of a sample."""
+
+    def __init__(self, current):
+        self.current = current
+
+    def collect(self):
+        system = self.current['system']
+        yield GaugeMetricFamily('system_cpu_utilization', 'CPU utilization since the previous sample, 0 to 1',
+                                value=system['cpu'] / 100)
+        memory = GaugeMetricFamily('system_memory_usage_bytes', 'Memory in use', labels=['state'])
+        memory.add_metric(['used'], system['memory_used'])
+        yield memory
+        yield GaugeMetricFamily('system_memory_limit_bytes', 'Total memory', value=system['memory_total'])
+        usage = GaugeMetricFamily('system_filesystem_usage_bytes', 'Space of the file system', labels=['mountpoint', 'state'])
+        usage.add_metric([MOUNTPOINT, 'free'], system['disk_free'])
+        usage.add_metric([MOUNTPOINT, 'used'], system['disk_total'] - system['disk_free'])
+        yield usage
+        if system['disk_total']:
+            utilization = GaugeMetricFamily('system_filesystem_utilization', 'Used part of the file system, 0 to 1',
+                                            labels=['mountpoint'])
+            utilization.add_metric([MOUNTPOINT], 1 - system['disk_free'] / system['disk_total'])
+            yield utilization
+        for period in ('1m', '5m', '15m'):
+            yield GaugeMetricFamily(f'system_cpu_load_average_{period}', f'Load average over {period}',
+                                    value=system[f'load{period[:-1]}'])
+        network = CounterMetricFamily('system_network_io_bytes', 'Bytes received and sent', labels=['device', 'direction'])
+        for name, (received, sent) in self.current['counters'].items():
+            network.add_metric([name, 'receive'], received)
+            network.add_metric([name, 'transmit'], sent)
+        yield network
+        vpn = GaugeMetricFamily('vpn_router_clients', 'Connected VPN clients; site_to_site is 1 while the tunnel is up',
+                                labels=['kind'])
+        for kind, count in self.current['clients'].items():
+            if count is not None:
+                vpn.add_metric([kind], count)
+        yield vpn
+
+
+def authorized(header, account):
+    """Whether an Authorization header holds the password of the service account; LDAP errors propagate."""
+    if not header.startswith('Basic '):
+        return False
+    try:
+        name, _, password = base64.b64decode(header[6:].strip(), validate=True).decode().partition(':')
+    except ValueError:
+        return False
+    if name != account:
+        return False
+    try:
+        with vpnrouter_users.session() as connection:
+            if not vpnrouter_users.service(vpnrouter_users.entry(connection, name)):
+                return False
+        vpnrouter_users.login(name, password, None)
+    except vpnrouter_users.Failure:
+        return False
+    return True
+
+
+class Handler(BaseHTTPRequestHandler):
+    protocol_version = 'HTTP/1.1'
+
+    def client(self):
+        """The client address: the last X-Forwarded-For entry of a call through Caddy on the loopback address, else the peer."""
+        peer = self.client_address[0]
+        forwarded = self.headers.get('X-Forwarded-For', '')
+        if peer == vpnrouter_net.LOOPBACK and forwarded.strip():
+            return forwarded.split(',')[-1].strip()
+        return peer
+
+    def answer(self, send_body):
+        self.principal = None
+        extra = []
+        path = self.path.split('?', 1)[0]
+        account = str(section(read_json(CONFIG_FILE), 'metrics').get('service_account',
+                                                                       vpnrouter.SCHEMA['metrics']['service_account'])).strip()
+        with _latest_lock:
+            current = _latest['sample']
+        if path != '/metrics':
+            body, kind, code = b'Not found\n', 'text/plain; charset=utf-8', 404
+        elif not account:
+            body, kind, code = b'metrics.service_account is not set\n', 'text/plain; charset=utf-8', 503
+        else:
+            try:
+                allowed = authorized(self.headers.get('Authorization', ''), account)
+            except (ldap.LDAPError, OSError) as exc:
+                allowed = None
+                body, kind, code = f'the user directory failed: {exc}\n'.encode(), 'text/plain; charset=utf-8', 500
+            if allowed is False:
+                body, kind, code = b'Unauthorized\n', 'text/plain; charset=utf-8', 401
+                extra.append(('WWW-Authenticate', 'Basic realm="vpn-router metrics", charset="UTF-8"'))
+            elif allowed:
+                self.principal = account
+                if current is None:
+                    body, kind, code = b'no sample yet\n', 'text/plain; charset=utf-8', 503
+                else:
+                    registry = CollectorRegistry()
+                    registry.register(Sample(current))
+                    body, kind, code = generate_latest(registry), CONTENT_TYPE_LATEST, 200
+        self.send_response(code)
+        self.send_header('Content-Type', kind)
+        self.send_header('Content-Length', str(len(body)))
+        self.send_header('Cache-Control', 'no-store')
+        for name, value in extra:
+            self.send_header(name, value)
+        self.end_headers()
+        if send_body:
+            self.wfile.write(body)
+
+    def do_GET(self):
+        self.answer(True)
+
+    def do_HEAD(self):
+        self.answer(False)
+
+    def log_message(self, format, *args):
+        principal = getattr(self, 'principal', None) or '-'
+        sys.stderr.write('%s - %s [%s] %s\n' % (self.client(), principal, self.log_date_time_string(), format % args))
+
+
+def wanted():
+    """Where the service listens: the addresses of the interfaces metrics.listen names and LOOPBACK, at metrics.port."""
+    configuration = read_json(CONFIG_FILE)
+    metrics = section(configuration, 'metrics')
+    defaults = vpnrouter.SCHEMA['metrics']
+    if metrics.get('enabled', defaults['enabled']) is False:
+        return [], 'metrics are disabled in the configuration'
+    port = metrics.get('port', defaults['port'])
+    if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+        port = defaults['port']
+    addresses = vpnrouter_net.listen_addresses(configuration, metrics.get('listen', defaults['listen']))
+    if not addresses:
+        return [], 'the addresses to listen on are not known yet'
+    return [(address, port) for address in [*addresses, vpnrouter_net.LOOPBACK]], ''
+
+
+def main():
+    signal.signal(signal.SIGTERM, lambda *_: sys.exit(0))
+    threading.Thread(target=collector_loop, name='collector', daemon=True).start()
+    try:
+        vpnrouter_serve.serve(wanted, Handler, log, DISCOVERY_SECONDS)
+    except KeyboardInterrupt:
+        pass
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main())
@@ -16,10 +16,12 @@ firewall and NAT rules are written against them, so choosing the wrong one
 would be a silent and security-relevant mistake.
 """

+import grp
 import json
 import os
 import pathlib
 import re
+import secrets
 import socket
 import subprocess
 import sys
@@ -58,6 +60,15 @@ MANAGER_CONFIG = pathlib.Path('/etc/vpn-router-manager/manager.json')
 MANAGER_ADMIN  = pathlib.Path('/etc/vpn-router-manager/admin.json')
 MANAGER_PORT   = 7080

+#: The password of the metrics service account, which setup makes and keeps (root only).
+METRICS_SECRET = pathlib.Path('/etc/vpn-router/metrics.secret')
+
+#: The configuration of Caddy, the HTTPS proxy, which the package's drop-in for caddy.service names;
+#: Caddy runs as the user and group CADDY_GROUP, which the caddy package creates.
+CADDYFILE   = pathlib.Path('/etc/caddy/vpn-router.Caddyfile')
+CADDY_UNIT  = 'caddy.service'
+CADDY_GROUP = 'caddy'
+
 FILTER_ANCHOR = '# End required lines'

 #: Configuration options left out wherever the configuration is shown.
@@ -71,6 +82,8 @@ BLOCKS = (
    ('# WEB RULES START',           '# WEB RULES END'),
    ('# BOOTSTRAP RULES START',     '# BOOTSTRAP RULES END'),
    ('# MANAGER RULES START',       '# MANAGER RULES END'),
+    ('# HTTPS RULES START',         '# HTTPS RULES END'),
+    ('# METRICS RULES START',       '# METRICS RULES END'),
    ('# ROUTER FORWARD RULES START', '# ROUTER FORWARD RULES END'),
    ('# ROUTER NAT RULES START',    '# ROUTER NAT RULES END'),
    ('# ROUTER MSS RULES START',    '# ROUTER MSS RULES END'),
@@ -215,11 +228,13 @@ def filter_block(ctx):
                ]
        lines += ['# P2S DNS RULES END']

-    if ctx['web_enabled'] and ctx['int_iface']:
+    # The web service, the Router Manager and the metrics service choose their interfaces themselves, so their ports are open on both.
+    interfaces = [name for name in (ctx['int_iface'], ctx['wan_iface']) if name]
+    if ctx['web_enabled'] and interfaces:
        lines += [
            '',
            '# WEB RULES START',
-            f'-A ufw-before-input -i {ctx["int_iface"]} -p tcp --dport {ctx["web_port"]} -j ACCEPT',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {ctx["web_port"]} -j ACCEPT' for name in interfaces),
            '# WEB RULES END',
        ]

@@ -231,15 +246,37 @@ def filter_block(ctx):
            '# BOOTSTRAP RULES END',
        ]

-    if MANAGER.exists() and ctx['int_iface']:
+    if MANAGER.exists() and interfaces:
        port = manager_port()
        lines += [
            '',
            '# MANAGER RULES START',
-            f'-A ufw-before-input -i {ctx["int_iface"]} -p tcp --dport {port} -j ACCEPT',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {port} -j ACCEPT' for name in interfaces),
            '# MANAGER RULES END',
        ]

+    if vpnrouter.metrics_ready(ctx) and interfaces:
+        lines += [
+            '',
+            '# METRICS RULES START',
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {ctx["metrics_port"]} -j ACCEPT' for name in interfaces),
+            '# METRICS RULES END',
+        ]
+
+    # Let's Encrypt reaches the HTTP challenge on the external interface; the HTTPS ports are open on both.
+    if vpnrouter.https_ready(ctx) and interfaces:
+        ports = [port for wanted, port in ((ctx['web_enabled'], ctx['https_web_port']),
+                                           (MANAGER.exists(), ctx['https_manager_port']),
+                                           (vpnrouter.metrics_ready(ctx), ctx['metrics_https_port'])) if wanted]
+        lines += [
+            '',
+            '# HTTPS RULES START',
+            *([f'-A ufw-before-input -i {ctx["wan_iface"]} -p tcp --dport {vpnrouter.ACME_HTTP_PORT} -j ACCEPT']
+              if ctx['wan_iface'] else []),
+            *(f'-A ufw-before-input -i {name} -p tcp --dport {port} -j ACCEPT' for name in interfaces for port in ports),
+            '# HTTPS RULES END',
+        ]
+
    if vpnrouter.routing_ready(ctx):
        lines += ['', '# ROUTER FORWARD RULES START']
        for subnet in ctx['local_cidr_list']:
@@ -416,6 +453,57 @@ def manage_admin():
    return ''


+def manage_metrics_account(ctx):
+    """Keep the service account metrics.service_account names, whose password is in METRICS_SECRET; the problem, or ''.
+
+    While metrics are enabled, setup owns the account: it adds it as a service account with a random password when
+    it is missing, and gives it a new random password, ending any lockout, when METRICS_SECRET is missing or does not
+    hold its password. A disabled account is left as it is. An account of that name that is not a service account is
+    left alone and is a problem.
+    """
+    if not vpnrouter.metrics_ready(ctx):
+        return ''
+    name = ctx['metrics_service_account']
+    try:
+        vpnrouter_users.check_name(name)
+        try:
+            password = METRICS_SECRET.read_text(encoding='utf-8').strip()
+        except OSError:
+            password = ''
+        with vpnrouter_users.session() as connection:
+            try:
+                current = vpnrouter_users.entry(connection, name)
+            except vpnrouter_users.Failure as failure:
+                if failure.status != 3:
+                    raise
+                current = None
+            if current is not None and not vpnrouter_users.service(current):
+                return f'metrics.service_account: {name} is a user, not a service account'
+            # An administrator who disabled the account meant it; its password is left as it is.
+            if current is not None and not vpnrouter_users.summary(current)['enabled']:
+                return ''
+            valid = False
+            if current is not None and password:
+                try:
+                    vpnrouter_users.login(name, password, None)
+                    valid = True
+                except vpnrouter_users.Failure:
+                    pass
+            if not valid:
+                password = secrets.token_urlsafe(32)
+                METRICS_SECRET.touch(mode=0o600)
+                METRICS_SECRET.chmod(0o600)
+                METRICS_SECRET.write_text(password + '\n', encoding='utf-8')
+                if current is None:
+                    vpnrouter_users.add(connection, name, password, {}, service=True)
+                else:
+                    vpnrouter_users.passwd(connection, name, password)
+                    vpnrouter_users.unlock(connection, name)
+    except (OSError, ldap.LDAPError, vpnrouter_users.Failure) as exc:
+        return f'the metrics service account cannot be kept: {exc}'
+    return ''
+
+
 def manage_openvpn(ctx, changed):
    """Run the OpenVPN server when it is configured, and stop it when it is not."""
    unit = 'openvpn-server@vpn-router'
@@ -431,6 +519,47 @@ def manage_openvpn(ctx, changed):
        run(['systemctl', 'restart', unit], check=False)


+def manage_caddy(ctx):
+    """Run Caddy, the HTTPS proxy of the web service, the Router Manager and the metrics service, while HTTPS is ready, and stop it when not.
+
+    CADDYFILE serves the web service on https.web_port, while the manager is installed the
+    manager on https.manager_port, and while metrics are enabled the metrics service on
+    metrics.https_port, all for wan.local_fqdn with a certificate from Let's Encrypt, and all
+    calling the service on its loopback address.
+    """
+    if not vpnrouter.https_ready(ctx):
+        vpnrouter.remove(CADDYFILE)
+        if unit_is_active(CADDY_UNIT):
+            run(['systemctl', 'disable', '--now', CADDY_UNIT], check=False)
+        return
+
+    try:
+        group = grp.getgrnam(CADDY_GROUP).gr_gid
+    except KeyError:
+        fail(f'the group {CADDY_GROUP} does not exist; is the caddy package installed?')
+    caddy_ctx = dict(ctx, manager_port=manager_port() if MANAGER.exists() else 0)
+    changed = vpnrouter.render(vpnrouter._jinja_env(), caddy_ctx, 'Caddyfile.j2', CADDYFILE, 0o640)
+    os.chown(CADDYFILE, 0, group)
+    if not unit_is_active(CADDY_UNIT):
+        run(['systemctl', 'enable', '--now', CADDY_UNIT], check=False)
+    elif changed:
+        run(['systemctl', 'reload', CADDY_UNIT], check=False)
+
+
+def manage_metrics(ctx):
+    """Run the metrics service while metrics are enabled, and stop it when not.
+
+    The service reads its settings itself, so it is restarted only to run the code of a new package version, which
+    every run of setup after an upgrade does.
+    """
+    unit = 'vpn-router-metrics.service'
+    if not vpnrouter.metrics_ready(ctx):
+        run(['systemctl', 'disable', '--now', unit], check=False)
+        return
+    run(['systemctl', 'enable', unit], check=False)
+    run(['systemctl', 'restart', unit], check=False)
+
+
 def run_platform_setup(cfg, ctx):
    """Let the platform module apply its own state, if it defines any."""
    module = vpnrouter.platform_module(cfg)
@@ -572,8 +701,14 @@ def main():
        failed_step = 'Router Manager admin'
        progress('running', failed_step)
        problem = manage_admin()
+    if not problem:
+        failed_step = 'metrics service account'
+        progress('running', failed_step)
+        problem = manage_metrics_account(ctx)
    progress('running', 'OpenVPN')
    manage_openvpn(ctx, changed)
+    progress('running', 'HTTPS proxy')
+    manage_caddy(ctx)

    if 'resolved' in changed:
        progress('running', 'resolver')
@@ -585,6 +720,8 @@ def main():
    refresh_docker_rules()
    progress('running', 'web service state')
    refresh_web(cfg, ctx)
+    progress('running', 'metrics service')
+    manage_metrics(ctx)
    if problem:
        progress('failed', failed_step, problem)
        print(f'vpn-router: error: {problem}', file=sys.stderr)
@@ -12,6 +12,7 @@ import re
 import shutil
 import subprocess
 import sys
+import urllib.parse

 import jinja2

@@ -21,7 +22,7 @@ if str(LIB_DIR) not in sys.path:

 import vpnrouter_ldap
 import vpnrouter_platforms
-from vpnrouter_net import ConfigError, detect_interfaces, interface_addresses, ip_output
+from vpnrouter_net import DEFAULT_LISTEN, LISTEN_CHOICES, LOOPBACK, ConfigError, detect_interfaces, interface_addresses, ip_output

 CONFIG_FILE  = pathlib.Path('/etc/vpn-router/vpn-router.json')
 TEMPLATE_DIR = pathlib.Path('/usr/share/vpn-router/templates')
@@ -54,9 +55,27 @@ SCHEMA = {
    'wireguard':  {'enabled': False, 'address': '', 'listen_port': 51820},
    'openvpn':    {'enabled': False, 'address_pool': '', 'port': 1194, 'protocol': 'udp'},
    'docker':     {'mode': 'auto', 'exposed_ports': []},
-    'web':        {'enabled': True, 'port': 7081, 'database': '', 'trusted_proxies': []},
+    'web':        {'enabled': True, 'listen': DEFAULT_LISTEN, 'port': 7081, 'database': '', 'trusted_proxies': [],
+                   'status_content': 'basic'},
+    'https':      {'enabled': True, 'email': '', 'web_port': 7444, 'manager_port': 7443},
+    'metrics':    {'enabled': True, 'listen': 'internal', 'port': 9464, 'https_port': 9465, 'service_account': 'metrics',
+                   'otlp_endpoint': '', 'otlp_username': '', 'otlp_password': '',
+                   'keep_details': '24 hours', 'keep_hourly': '1 month', 'keep_daily': '3 months',
+                   'keep_monthly': '1 year', 'keep_yearly': '10 years'},
 }

+#: The retention settings of the metrics, from the details to the yearly summaries.
+METRICS_KEEP = ('keep_details', 'keep_hourly', 'keep_daily', 'keep_monthly', 'keep_yearly')
+
+#: A retention period as PostgreSQL reads an interval: a count and a unit.
+METRICS_INTERVAL = re.compile(r'^[1-9]\d{0,4} (hour|day|month|year)s?$')
+
+#: The port of Let's Encrypt's HTTP challenge, which Caddy answers while HTTPS is on.
+ACME_HTTP_PORT = 80
+
+#: What / and /status of the web service show, web.status_content, from the least to the most.
+STATUS_CONTENTS = ('basic', 'standard', 'full')
+
 DOCKER_MODES = ('auto', 'on', 'off')

 OPENVPN_PROTOCOLS = ('udp', 'tcp')
@@ -259,9 +278,57 @@ def validate(cfg):
    if isinstance(web_port, bool) or not isinstance(web_port, int) or not 1 <= web_port <= 65535:
        raise ConfigError(f'web.port: {web_port!r} is not a valid port')

+    web_listen = _get(cfg, 'web', 'listen')
+    if web_listen not in LISTEN_CHOICES:
+        raise ConfigError(
+            f'web.listen: {web_listen!r} is not one of {", ".join(LISTEN_CHOICES)}')
+
+    status_content = _get(cfg, 'web', 'status_content')
+    if status_content not in STATUS_CONTENTS:
+        raise ConfigError(
+            f'web.status_content: {status_content!r} is not one of {", ".join(STATUS_CONTENTS)}')
+
+    https_ports = []
+    for option in ('web_port', 'manager_port'):
+        port = _get(cfg, 'https', option)
+        if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+            raise ConfigError(f'https.{option}: {port!r} is not a valid port')
+        if port == ACME_HTTP_PORT:
+            raise ConfigError(f'https.{option}: {port} is the port of the HTTP challenge')
+        https_ports.append(port)
+    if https_ports[0] == https_ports[1]:
+        raise ConfigError('https.web_port and https.manager_port must differ')
+
    for item in _get_list(cfg, 'web', 'trusted_proxies'):
        _check_address(item, 'web.trusted_proxies')

+    taken = {web_port: 'web.port', ACME_HTTP_PORT: 'the HTTP challenge',
+             https_ports[0]: 'https.web_port', https_ports[1]: 'https.manager_port'}
+    for option in ('port', 'https_port'):
+        port = _get(cfg, 'metrics', option)
+        if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
+            raise ConfigError(f'metrics.{option}: {port!r} is not a valid port')
+        if port in taken:
+            raise ConfigError(f'metrics.{option}: {port} is the port of {taken[port]}')
+        taken[port] = f'metrics.{option}'
+
+    metrics_listen = _get(cfg, 'metrics', 'listen')
+    if metrics_listen not in LISTEN_CHOICES:
+        raise ConfigError(
+            f'metrics.listen: {metrics_listen!r} is not one of {", ".join(LISTEN_CHOICES)}')
+
+    endpoint = _get(cfg, 'metrics', 'otlp_endpoint')
+    if endpoint and urllib.parse.urlsplit(endpoint).scheme not in ('http', 'https'):
+        raise ConfigError(f'metrics.otlp_endpoint: {endpoint!r} is not an http or https URL')
+    if bool(_get(cfg, 'metrics', 'otlp_username')) != bool(_get(cfg, 'metrics', 'otlp_password')):
+        raise ConfigError('metrics.otlp_username and metrics.otlp_password are given together')
+
+    for option in METRICS_KEEP:
+        keep = _get(cfg, 'metrics', option)
+        if not METRICS_INTERVAL.match(keep):
+            raise ConfigError(
+                f'metrics.{option}: {keep!r} is not a count and a unit, such as "24 hours" or "3 months"')
+
    docker_mode = _get(cfg, 'docker', 'mode')
    if docker_mode not in DOCKER_MODES:
        raise ConfigError(
@@ -275,6 +342,13 @@ def validate(cfg):
            raise ConfigError(
                f'docker.exposed_ports: {item!r} is not a port or a port range')
        weight += 2 if ':' in item else 1
+        first, _, last = item.partition(':')
+        if _get(cfg, 'https', 'enabled'):
+            for port in (ACME_HTTP_PORT, *https_ports):
+                if int(first) <= port <= int(last or first):
+                    raise ConfigError(
+                        f'docker.exposed_ports: {item!r} takes port {port}, which Caddy serves while '
+                        'https.enabled is true')
    if weight > DOCKER_PORT_LIMIT:
        raise ConfigError(
            f'docker.exposed_ports: at most {DOCKER_PORT_LIMIT} ports are allowed, '
@@ -443,6 +517,15 @@ def build_context(cfg, local_id_override=None):
        'ldap_users':      vpnrouter_ldap.USERS,
        'web_enabled':     _get(cfg, 'web', 'enabled'),
        'web_port':        _get(cfg, 'web', 'port'),
+        'https_enabled':   _get(cfg, 'https', 'enabled'),
+        'https_email':     _get(cfg, 'https', 'email'),
+        'https_web_port':  _get(cfg, 'https', 'web_port'),
+        'https_manager_port': _get(cfg, 'https', 'manager_port'),
+        'metrics_enabled': _get(cfg, 'metrics', 'enabled'),
+        'metrics_port':    _get(cfg, 'metrics', 'port'),
+        'metrics_https_port': _get(cfg, 'metrics', 'https_port'),
+        'metrics_service_account': _get(cfg, 'metrics', 'service_account'),
+        'loopback':        LOOPBACK,
    }


@@ -472,6 +555,16 @@ def openvpn_ready(ctx):
    return bool(ctx['openvpn_enabled'] and ctx['openvpn_pool'] and ctx['local_fqdn'])


+def https_ready(ctx):
+    """Caddy serves HTTPS once it is enabled and wan.local_fqdn names the certificate."""
+    return bool(ctx['https_enabled'] and ctx['local_fqdn'])
+
+
+def metrics_ready(ctx):
+    """The metrics service collects, keeps and serves the metrics while metrics.enabled is true."""
+    return bool(ctx['metrics_enabled'])
+
+
 def _jinja_env():
    return jinja2.Environment(
        loader=jinja2.FileSystemLoader(str(TEMPLATE_DIR)),
@@ -53,7 +53,7 @@ OVERLAYS = ('ppolicy', 'otp')
 #: The package's own schema, under an OID of the UUID arc 2.25 (ITU-T X.667): attribute types
 #: under .1 and object classes under .2. vpnRouterAccount, auxiliary, adds properties of the
 #: package to a user of either kind: mail, for a Manager-only account, and vpnRouterScope,
-#: authorization scopes that nothing reads yet.
+#: authorization scopes, of which service marks a service account.
 SCHEMA_OID = '2.25.98477352595735834532404256531620013001'
 SCHEMA_NAME = 'vpn-router'
 SCHEMA_ATTRIBUTE_TYPES = (
@@ -0,0 +1,173 @@
+"""The metrics of the router in PostgreSQL, for the metrics service and the web service.
+
+The metrics service writes one detail row per minute to the three detail tables, of TABLES:
+metrics_system (CPU, memory, disk and load averages), metrics_network (bytes per second
+received and sent per interface) and metrics_vpn (clients per kind). Each detail table has four
+summary tables, of LEVELS: <table>_hourly from the details, <table>_daily from the hourly,
+<table>_monthly from the daily and <table>_yearly from the monthly rows. A summary row has the
+start of its period, in UTC, and the average and the maximum of each value over the period: of
+the details for the hourly rows, else the average of the averages and the maximum of the maxima
+below. A period is summarized once it is complete; summarize() catches up every complete period
+after the last summarized one, so a stopped service loses no summary of what was written.
+
+collect_garbage() deletes the rows older than the retention of their level, metrics.keep_*;
+the service runs it on start and once a day. history() answers the views of the Metrics tab.
+
+The tables are in the database of the refresh tokens (vpnrouter_auth.connection_string) and are
+created when missing. Every failure of the database raises DatabaseError.
+"""
+
+import contextlib
+
+import psycopg
+
+import vpnrouter_auth
+
+#: The detail tables: their key columns besides time, and their value columns.
+TABLES = {
+    'metrics_system': ((), ('cpu', 'memory_used', 'memory_total', 'disk_free', 'disk_total', 'load1', 'load5', 'load15')),
+    'metrics_network': (('interface',), ('rx', 'tx')),
+    'metrics_vpn': (('kind',), ('clients',)),
+}
+
+#: The summary levels, from the finest: the suffix of the tables, the period of date_trunc and the retention setting.
+LEVELS = (
+    ('hourly', 'hour', 'keep_hourly'),
+    ('daily', 'day', 'keep_daily'),
+    ('monthly', 'month', 'keep_monthly'),
+    ('yearly', 'year', 'keep_yearly'),
+)
+
+#: The kinds of VPN clients of metrics_vpn; site_to_site is 1 while the tunnel is up.
+VPN_KINDS = ('p2s', 'openvpn', 'wireguard', 'site_to_site')
+
+#: The views of history(): the summary level read (None: the details), the bucket and the span.
+RANGES = {
+    'hour': (None, '1 minute', '1 hour'),
+    'day': (None, '10 minutes', '1 day'),
+    'month': ('hourly', '6 hours', '1 month'),
+    'year': ('monthly', '1 month', '1 year'),
+}
+
+
+class DatabaseError(Exception):
+    """The metrics database failed."""
+
+
+def schema():
+    """The statements that create the detail and the summary tables."""
+    statements = []
+    for table, (keys, values) in TABLES.items():
+        key_columns = ''.join(f', {key} text NOT NULL' for key in keys)
+        primary = ', '.join(('time', *keys))
+        detail = ''.join(f', {value} double precision' for value in values)
+        statements.append(f'CREATE TABLE IF NOT EXISTS {table} (time timestamptz NOT NULL{key_columns}{detail}, '
+                          f'PRIMARY KEY ({primary}))')
+        summary = ''.join(f', {value}_avg double precision, {value}_max double precision' for value in values)
+        for suffix, _, _ in LEVELS:
+            statements.append(f'CREATE TABLE IF NOT EXISTS {table}_{suffix} (time timestamptz NOT NULL{key_columns}{summary}, '
+                              f'PRIMARY KEY ({primary}))')
+    return statements
+
+
+@contextlib.contextmanager
+def database(cfg):
+    """A connection to the metrics database, with its tables, closed at the end; DatabaseError on any failure."""
+    try:
+        with psycopg.connect(vpnrouter_auth.connection_string(cfg), autocommit=True) as connection:
+            for statement in schema():
+                connection.execute(statement)
+            yield connection
+    except (psycopg.Error, OSError) as exc:
+        raise DatabaseError(f'the metrics database failed: {exc}') from exc
+
+
+def write(connection, system, network, vpn):
+    """Write a sample as the detail rows of the current minute.
+
+    system maps the values of metrics_system to numbers; network maps an interface to its rx and
+    tx; vpn maps a kind of VPN_KINDS to its clients. A value that is None is written as NULL.
+    """
+    with connection.transaction():
+        minute = connection.execute("SELECT date_trunc('minute', now(), 'UTC')").fetchone()[0]
+        names = TABLES['metrics_system'][1]
+        connection.execute(f"INSERT INTO metrics_system (time, {', '.join(names)}) "
+                           f"VALUES (%s{', %s' * len(names)}) ON CONFLICT DO NOTHING",
+                           (minute, *(system.get(name) for name in names)))
+        for interface, (rx, tx) in network.items():
+            connection.execute('INSERT INTO metrics_network (time, interface, rx, tx) VALUES (%s, %s, %s, %s) '
+                               'ON CONFLICT DO NOTHING', (minute, interface, rx, tx))
+        for kind, clients in vpn.items():
+            connection.execute('INSERT INTO metrics_vpn (time, kind, clients) VALUES (%s, %s, %s) ON CONFLICT DO NOTHING',
+                               (minute, kind, clients))
+
+
+def summarize(connection, level):
+    """Summarize the complete periods of a level of LEVELS that are not summarized yet, for every detail table."""
+    index = [suffix for suffix, _, _ in LEVELS].index(level)
+    _, period, _ = LEVELS[index]
+    for table, (keys, values) in TABLES.items():
+        target = f'{table}_{level}'
+        source = table if index == 0 else f'{table}_{LEVELS[index - 1][0]}'
+        if index == 0:
+            aggregates = ', '.join(f'avg({value}), max({value})' for value in values)
+        else:
+            aggregates = ', '.join(f'avg({value}_avg), max({value}_max)' for value in values)
+        columns = ', '.join(('time', *keys, *(f'{value}_{kind}' for value in values for kind in ('avg', 'max'))))
+        groups = ''.join(f', {key}' for key in keys)
+        connection.execute(
+            f"INSERT INTO {target} ({columns}) "
+            f"SELECT date_trunc('{period}', time, 'UTC') AS period{groups}, {aggregates} FROM {source} "
+            f"WHERE time < date_trunc('{period}', now(), 'UTC') "
+            f"AND time >= coalesce((SELECT max(time) FROM {target}) + interval '1 {period}', '-infinity') "
+            f"GROUP BY period{groups} ON CONFLICT DO NOTHING")
+
+
+def collect_garbage(connection, cfg):
+    """Delete the rows older than the retention of their level: metrics.keep_details, keep_hourly and so on."""
+    metrics = cfg['metrics']
+    for table in TABLES:
+        connection.execute(f'DELETE FROM {table} WHERE time < now() - %s::interval', (metrics['keep_details'],))
+        for suffix, _, keep in LEVELS:
+            connection.execute(f'DELETE FROM {table}_{suffix} WHERE time < now() - %s::interval', (metrics[keep],))
+
+
+def history(connection, view):
+    """The points of a view of RANGES, oldest first, each with the start of its bucket in Unix seconds.
+
+    A point has the average and the maximum of each value of metrics_system, network, which maps
+    each interface to its rx and tx, and clients, which maps each kind of VPN client to its
+    clients; a value without data is None.
+    """
+    level, bucket, span = RANGES[view]
+
+    def rows(table):
+        keys, values = TABLES[table]
+        source = table if level is None else f'{table}_{level}'
+        if level is None:
+            aggregates = ', '.join(f'avg({value}), max({value})' for value in values)
+        else:
+            aggregates = ', '.join(f'avg({value}_avg), max({value}_max)' for value in values)
+        start = (f"date_bin('{bucket}', time, timestamptz '2000-01-01 00:00:00+00')" if view != 'year'
+                 else "date_trunc('month', time, 'UTC')")
+        groups = ''.join(f', {key}' for key in keys)
+        return connection.execute(
+            f"SELECT extract(epoch FROM {start})::bigint AS bucket{groups}, {aggregates} FROM {source} "
+            f"WHERE time >= now() - interval '{span}' GROUP BY bucket{groups} ORDER BY bucket").fetchall()
+
+    def pairs(row, values):
+        return {value: {'avg': row[2 * index], 'max': row[2 * index + 1]} for index, value in enumerate(values)}
+
+    points = {}
+
+    def point(start):
+        return points.setdefault(start, {'time': start, 'network': {}, 'clients': {}})
+
+    for row in rows('metrics_system'):
+        point(row[0]).update(pairs(row[1:], TABLES['metrics_system'][1]))
+    for row in rows('metrics_network'):
+        point(row[0])['network'][row[1]] = pairs(row[2:], TABLES['metrics_network'][1])
+    for row in rows('metrics_vpn'):
+        point(row[0])['clients'][row[1]] = pairs(row[2:], TABLES['metrics_vpn'][1])['clients']
+    empty = {value: {'avg': None, 'max': None} for value in TABLES['metrics_system'][1]}
+    return {'range': view, 'bucket': bucket, 'points': [{**empty, **points[start]} for start in sorted(points)]}
@@ -7,6 +7,15 @@ this module too.
 import pathlib
 import subprocess

+#: The values of web.listen and of the Router Manager's listen: the interfaces a service listens on.
+LISTEN_CHOICES = ('internal', 'external', 'both')
+
+#: The interfaces a service listens on when it is not set.
+DEFAULT_LISTEN = 'both'
+
+#: The address every service also listens on, where the HTTPS proxy calls it.
+LOOPBACK = '127.0.0.1'
+

 class ConfigError(Exception):
    """A setting is present but malformed."""
@@ -110,26 +119,58 @@ def internal_address(mode, internal, int_addr):
    return addresses[0] if addresses else ''


-def web_listen(configuration, default_port):
-    """Where the web service listens, from vpn-router.json read as configuration, as ((address, port), '').
+def external_address(mode, external):
+    """The router's address on the external interface, as general.mode directs, or '' when it is not known yet.

-    The address is the internal address as general.mode directs, the port web.port, else
-    default_port. While web.enabled is false or the address is not known, the answer is (None,
-    the reason).
+    auto works out which interface that is; the other modes read the address of interfaces.external.
    """
-    def section(name):
-        value = configuration.get(name)
-        return value if isinstance(value, dict) else {}
+    try:
+        if mode == 'auto':
+            external = detect_interfaces()[0]
+        addresses = interface_addresses(external, 'interfaces.external')
+    except ConfigError:
+        return ''
+    return addresses[0] if addresses else ''

-    web = section('web')
+
+def _section(configuration, name):
+    """A section of a configuration, or {} when it is missing or not an object."""
+    value = configuration.get(name)
+    return value if isinstance(value, dict) else {}
+
+
+def listen_addresses(configuration, choice):
+    """The addresses a service listens on for choice of LISTEN_CHOICES, from vpn-router.json read as configuration.
+
+    The internal address comes first; an address not known yet is left out. A choice that is not
+    one of LISTEN_CHOICES is DEFAULT_LISTEN. LOOPBACK is not among them; web_listen adds it.
+    """
+    if choice not in LISTEN_CHOICES:
+        choice = DEFAULT_LISTEN
+    general, interfaces, local = (_section(configuration, name) for name in ('general', 'interfaces', 'local'))
+    mode = str(general.get('mode') or 'manual')
+    addresses = []
+    if choice in ('internal', 'both'):
+        addresses.append(internal_address(mode, str(interfaces.get('internal') or ''), str(local.get('int_addr') or '')))
+    if choice in ('external', 'both'):
+        addresses.append(external_address(mode, str(interfaces.get('external') or '')))
+    return [address for address in addresses if address]
+
+
+def web_listen(configuration, default_port):
+    """Where the web service listens, from vpn-router.json read as configuration, as ([(address, port), ...], '').
+
+    The addresses are those of the interfaces web.listen names (listen_addresses), then
+    LOOPBACK, the port web.port, else default_port. While web.enabled is false or no address of
+    an interface is known, the answer is ([], the reason).
+    """
+    web = _section(configuration, 'web')
    if web.get('enabled', True) is False:
-        return None, 'the web service is disabled in the configuration'
+        return [], 'the web service is disabled in the configuration'
    port = web.get('port', default_port)
    if isinstance(port, bool) or not isinstance(port, int) or not 1 <= port <= 65535:
        port = default_port
-    general, interfaces, local = section('general'), section('interfaces'), section('local')
-    address = internal_address(str(general.get('mode') or 'manual'), str(interfaces.get('internal') or ''),
-                               str(local.get('int_addr') or ''))
-    if not address:
-        return None, 'the internal address is not known yet'
-    return (address, port), ''
+    addresses = listen_addresses(configuration, web.get('listen', DEFAULT_LISTEN))
+    if not addresses:
+        return [], 'the addresses to listen on are not known yet'
+    return [(address, port) for address in [*addresses, LOOPBACK]], ''
@@ -10,31 +10,37 @@ from http.server import ThreadingHTTPServer


 def serve(wanted, handler, log, interval):
-    """Work out where to listen every interval seconds with wanted, and run an HTTP server of handler there.
+    """Work out where to listen every interval seconds with wanted, and run an HTTP server of handler at each place.

-    wanted answers ((address, port), '') or (None, the reason not to listen). When the address or
-    the port changes, the server is stopped and a new one listens at the new place; while there is
-    no place or it cannot be bound, no server runs and the next round tries again. Every new
-    reason is logged with log. Does not return.
+    wanted answers ([(address, port), ...], '') or ([], the reason not to listen). A server whose
+    place is no longer wanted is stopped, and a new one listens at each new place; a place that
+    cannot be bound is tried again the next round. Every new message is logged with log. Does
+    not return.
    """
-    server, thread, listening, reported = None, None, None, None
+    servers, reported = {}, None
    while True:
-        target, reason = wanted()
-        if target != listening and server is not None:
+        targets, reason = wanted()
+        for target in [target for target in servers if target not in targets]:
+            server, thread = servers.pop(target)
            server.shutdown()
            server.server_close()
            thread.join()
-            server, listening = None, None
-        if target is not None and server is None:
+        messages = [reason] if reason else []
+        for target in targets:
+            if target in servers:
+                continue
            try:
                server = ThreadingHTTPServer(target, handler)
            except OSError as exc:
-                reason = f'cannot listen on {target[0]}:{target[1]}: {exc}'
-            else:
-                thread = threading.Thread(target=server.serve_forever, name='server', daemon=True)
-                thread.start()
-                listening, reason = target, f'serving on http://{target[0]}:{target[1]}'
-        if reason and reason != reported:
-            log(reason)
-            reported = reason
+                messages.append(f'cannot listen on {target[0]}:{target[1]}: {exc}')
+                continue
+            thread = threading.Thread(target=server.serve_forever, name=f'server {target[0]}', daemon=True)
+            thread.start()
+            servers[target] = (server, thread)
+        if servers:
+            messages.append('serving on ' + ', '.join(f'http://{address}:{port}' for address, port in servers))
+        message = '; '.join(messages)
+        if message and message != reported:
+            log(message)
+            reported = message
        time.sleep(interval)
@@ -0,0 +1,111 @@
+"""What the router's VPN systems report, for the web service and the metrics service.
+
+Each reader asks the running system once and answers None when it cannot be asked: swanctl for
+the IKE SAs, wg for the WireGuard peers and the OpenVPN server's status file for its clients.
+"""
+
+import subprocess
+import time
+
+COMMAND_TIMEOUT = 5
+
+OPENVPN_STATUS = '/run/openvpn-server/status-vpn-router.log'
+
+#: Seconds since its last handshake within which a WireGuard peer counts as connected.
+WIREGUARD_CONNECTED_SECONDS = 180
+
+
+def run(*args):
+    """The finished process of a command, or None when it cannot be run."""
+    try:
+        return subprocess.run(args, capture_output=True, text=True, timeout=COMMAND_TIMEOUT)
+    except (OSError, subprocess.TimeoutExpired):
+        return None
+
+
+def swanctl(command):
+    """The entries of a swanctl list command, or None when swanctl cannot be asked.
+
+    The --pretty output has one item per line: "name {" opens a section, "key = [" a list
+    whose items follow one per line, "}" and "]" close them, and "key = value" is a pair
+    whose value may contain spaces. Every "... event {" section at the top holds one
+    connection or SA; each becomes an entry with its name under "name". The closing
+    "... reply {" section is left out. Values stay strings, as swanctl prints them.
+    Output with more closing than opening lines gives None.
+    """
+    result = run('swanctl', command, '--pretty')
+    if result is None or result.returncode != 0:
+        return None
+    events = []
+    stack = []
+    for line in result.stdout.splitlines():
+        line = line.strip()
+        if not line:
+            continue
+        if line in ('}', ']'):
+            if not stack:
+                return None
+            stack.pop()
+        elif not stack:
+            section = {}
+            if line.endswith(' event {'):
+                events.append(section)
+            stack.append(section)
+        elif isinstance(stack[-1], list):
+            stack[-1].append(line)
+        elif line.endswith(' {'):
+            stack[-1][line[:-2]] = section = {}
+            stack.append(section)
+        elif line.endswith(' = ['):
+            stack[-1][line[:-4]] = items = []
+            stack.append(items)
+        else:
+            key, _, value = line.partition(' = ')
+            stack[-1][key] = value
+    return [dict(body, name=name) for event in events for name, body in event.items()]
+
+
+def established(connection):
+    """The number of established IKE SAs of the connection, or None when swanctl cannot be asked."""
+    sas = swanctl('--list-sas')
+    if sas is None:
+        return None
+    return sum(1 for sa in sas if sa['name'] == connection and sa.get('state') == 'ESTABLISHED')
+
+
+def wireguard_peers():
+    """One entry per WireGuard peer, with its handshake age and traffic, or None when wg0 is down."""
+    result = run('wg', 'show', 'wg0', 'dump')
+    if result is None or result.returncode != 0:
+        return None
+    now = int(time.time())
+    peers = []
+    for line in result.stdout.splitlines()[1:]:
+        fields = line.split('\t')
+        if len(fields) < 7:
+            continue
+        handshake = int(fields[4])
+        peers.append({
+            'handshake_seconds_ago': now - handshake if handshake else None,
+            'received_bytes': int(fields[5]),
+            'sent_bytes': int(fields[6]),
+        })
+    return peers
+
+
+def wireguard_connected():
+    """The number of WireGuard peers with a handshake in the last WIREGUARD_CONNECTED_SECONDS, or None when wg0 is down."""
+    peers = wireguard_peers()
+    if peers is None:
+        return None
+    return sum(1 for peer in peers
+               if peer['handshake_seconds_ago'] is not None and peer['handshake_seconds_ago'] < WIREGUARD_CONNECTED_SECONDS)
+
+
+def openvpn_clients():
+    """The number of connected OpenVPN clients, from the server's status file, or None when it cannot be read."""
+    try:
+        with open(OPENVPN_STATUS, encoding='utf-8') as handle:
+            return sum(1 for line in handle if line.startswith('CLIENT_LIST,'))
+    except OSError:
+        return None
@@ -6,8 +6,10 @@ password OpenVPN checks, and a client certificate of the router CA with the user
 common name, which OpenVPN and IKEv2 accept. A Manager-only account is an account,
 simpleSecurityObject and vpnRouterAccount (the package's schema) with a name, a password and
 optionally an e-mail address, no names, no certificate and so no VPN access; it is added when
-neither the first nor the last name is given, and can sign in to the web service. Users exist
-whether or not a P2S system is enabled.
+neither the first nor the last name is given, and can sign in to the web service. A service
+account is a Manager-only account with the scope SERVICE_SCOPE in vpnRouterScope, which
+vpn-router-setup adds and keeps for the metrics service, as metrics.service_account names it; it
+cannot sign in to the web service. Users exist whether or not a P2S system is enabled.

 A group is a groupOfNames in ou=groups with a name, which follows the rules of user names, an
 optional description and at least one member; a group cannot be empty, so the last member
@@ -62,7 +64,9 @@ EMAIL_MAX = 254
 #: The keys of the person attributes and their LDAP attributes.
 PERSON = (('first_name', 'givenName'), ('last_name', 'sn'), ('email', 'mail'))
 #: The attributes read for a user.
-ATTRIBUTES = ['uid', 'objectClass', 'pwdAccountLockedTime', 'givenName', 'sn', 'mail', 'oathTOTPToken']
+ATTRIBUTES = ['uid', 'objectClass', 'pwdAccountLockedTime', 'givenName', 'sn', 'mail', 'oathTOTPToken', 'vpnRouterScope']
+#: The vpnRouterScope of a service account.
+SERVICE_SCOPE = 'service'
 #: The object classes of a VPN user and of a Manager-only account.
 VPN_USER_CLASSES = [b'inetOrgPerson']
 MANAGER_ONLY_CLASSES = [b'account', b'simpleSecurityObject', b'vpnRouterAccount']
@@ -183,6 +187,11 @@ def manager_only(attributes):
    return b'account' in (value.lower() for value in attributes.get('objectClass', []))


+def service(attributes):
+    """Whether the entry is a service account."""
+    return SERVICE_SCOPE.encode() in (value.lower() for value in attributes.get('vpnRouterScope', []))
+
+
 def summary(attributes):
    """A user as the answers show it; a person attribute the entry does not have is None."""
    name = attributes['uid'][0].decode()
@@ -190,6 +199,7 @@ def summary(attributes):
    user = {
        'name': name,
        'manager_only': manager_only(attributes),
+        'service': service(attributes),
        'enabled': lock != LOCKED,
        'locked': lock not in (None, LOCKED) and locked_since(lock) > time.time() - vpnrouter_ldap.LOCKOUT_SECONDS,
        'certificate': certificate(name)[0].is_file(),
@@ -213,12 +223,15 @@ def list_users(connection):
    return {'users': sorted((summary(attributes) for _, attributes in found), key=lambda user: user['name'])}


-def add(connection, name, password, values):
+def add(connection, name, password, values, service=False):
    """Add a user: a VPN user with its certificate when values gives all three person attributes, a Manager-only account
-    with at most the e-mail address when it gives neither name."""
+    with at most the e-mail address when it gives neither name, and, with service, which only vpn-router-setup uses, a
+    service account, with at most the e-mail address too."""
    check_name(name)
    details = person(values, required=False)
    vpn_user = 'givenName' in details or 'sn' in details
+    if service and vpn_user:
+        raise Failure('a service account has no first or last name', 2)
    if vpn_user and len(details) != len(PERSON):
        raise Failure('give first_name, last_name and email for a VPN user, or at most email for a Manager-only account', 2)
    check_password(password)
@@ -229,6 +242,8 @@ def add(connection, name, password, values):
    else:
        # simpleSecurityObject requires a userPassword; passwd_s sets the real one at once.
        record = {'objectClass': MANAGER_ONLY_CLASSES, 'uid': [name.encode()], 'userPassword': [b'{CRYPT}!']}
+        if service:
+            record['vpnRouterScope'] = [SERVICE_SCOPE.encode()]
    record.update({attribute: [value.encode()] for attribute, value in details.items()})
    try:
        connection.add_s(dn_of(name), ldap.modlist.addModlist(record))
@@ -1,5 +1,5 @@
 #!/usr/bin/python3
-"""Serve the status of the router on its internal address.
+"""Serve the status of the router on its internal address, its external address or both, as web.listen sets.

 Run by vpn-router-web.service. Users are managed with vpnrouter_users, the module that
 vpn-router-user uses too.
@@ -18,8 +18,11 @@ Pages:
  /account the account of the signed-in user: its details, its password and its TOTP
           enrolment (see account())
  /auth    sign-in with a user's password and TOTP code, refresh and sign-out (see auth())
+  /metrics/history
+           the metrics the metrics service keeps, for a view: hour, day, month or year (see
+           metrics_history())

-/config, /users, /groups and /account need an HS256 JWT in an Authorization: Bearer header signed
+/config, /metrics/history, /users, /groups and /account need an HS256 JWT in an Authorization: Bearer header signed
 with vpnrouter_auth.WEB_KEY (see vpnrouter_auth.verify). A token of /auth names a user in sub;
 /account serves that user, and the other paths need a member of vpnrouter_users.ADMIN_GROUP. A
 token of vpn-router-token has the admin claim and names no user; it may call every path but
@@ -27,12 +30,15 @@ token of vpn-router-token has the admin claim and names no user; it may call eve
 add or take out its members, and remove one of its members. These paths and /auth are not
 served (404) while the key does not exist. /auth is limited to AUTH_LIMIT calls per client
 address in AUTH_WINDOW seconds; the address of a call from one of web.trusted_proxies, by
-default the address the service listens on, is the last entry of its X-Forwarded-For header.
+default the address the call came in on, is the last entry of its X-Forwarded-For header.

-/ and /status show only the status: whether the services run, the package version and the
-installed version of vpn-router-manager (manager_version, null when it is not installed), whether
-Docker is installed, and the state of site-to-site, road-warrior (IPsec P2S), OpenVPN and
-WireGuard. No configuration data, key or address is shown.
+/ and /status show only the status, as much as web.status_content says (see shown): basic, the
+default, the overall status, the time and the client's address (its address as for the rate limit
+below); standard also the package version, the installed version of vpn-router-manager
+(manager_version, null when it is not installed) and the number of active and other services; full
+whether each service runs, whether Docker is installed, and the state of site-to-site, road-warrior
+(IPsec P2S), OpenVPN and WireGuard. No configuration data or key is shown, and no address but the
+client's.

 The service first initializes, without listening: it makes the signing key and the refresh
 tokens' database (vpnrouter_auth), retrying every INIT_RETRY_SECONDS until both are ready and
@@ -40,10 +46,11 @@ logging each failure. Then it listens. Its unit starts it only once wait-for-lib
 in the linker cache, where psycopg looks it up.

 The service needs nothing else to start and does not end on its own. Every DISCOVERY_SECONDS it
-works out the internal address from /etc/vpn-router/vpn-router.json as general.mode directs,
-with web.port and web.enabled (vpnrouter_net.web_listen), and runs the server there
-(vpnrouter_serve.serve): it starts it, moves it when the address or the port changes, and stops
-it while the service is disabled or the address is not known. Every request reads what it needs when it is made: the signing
+works out from /etc/vpn-router/vpn-router.json the addresses of the interfaces web.listen names,
+internal, external or both, as general.mode directs, with web.port and web.enabled
+(vpnrouter_net.web_listen), and runs a server on each (vpnrouter_serve.serve): it starts them,
+moves them when an address or the port changes, and stops them while the service is disabled or
+no address is known. Every request reads what it needs when it is made: the signing
 key, the configuration, and the features of the router and the facts shown by /config from
 /run/vpn-router/web.json, which vpn-router-setup writes. Before setup has written that file
 the router has no features, and /config shows no configuration or interfaces.
@@ -53,10 +60,10 @@ import collections
 import json
 import os
 import signal
-import subprocess
 import sys
 import threading
 import time
+import urllib.parse
 from html import escape
 from http.server import BaseHTTPRequestHandler

@@ -66,9 +73,11 @@ import ldap

 import vpnrouter
 import vpnrouter_auth
+import vpnrouter_metrics
 import vpnrouter_net
 import vpnrouter_serve
 import vpnrouter_users
+from vpnrouter_status import established, openvpn_clients, run, swanctl, wireguard_peers

 STATE_FILE = '/run/vpn-router/web.json'
 CONFIG_FILE = '/etc/vpn-router/vpn-router.json'
@@ -81,7 +90,6 @@ DEFAULT_PORT = 7081

 #: Seconds between two discoveries of where the service should listen.
 DISCOVERY_SECONDS = 30
-COMMAND_TIMEOUT = 5
 CACHE_SECONDS = 2

 #: The calls of /auth allowed per client address in AUTH_WINDOW seconds.
@@ -93,8 +101,6 @@ TAILWIND = 'https://cdn.jsdelivr.net/npm/@tailwindcss/browser@4'
 #: Seconds after which the status page in a browser reloads itself.
 REFRESH_SECONDS = 60

-OPENVPN_STATUS = '/run/openvpn-server/status-vpn-router.log'
-
 #: The largest request body accepted, in bytes.
 BODY_LIMIT = 4096

@@ -134,14 +140,6 @@ def current():
    return dict(read_json(STATE_FILE), key=vpnrouter_auth.key())


-def run(*args):
-    """The finished process of a command, or None when it cannot be run."""
-    try:
-        return subprocess.run(args, capture_output=True, text=True, timeout=COMMAND_TIMEOUT)
-    except (OSError, subprocess.TimeoutExpired):
-        return None
-
-
 def unit_state(unit):
    result = run('systemctl', 'is-active', unit)
    return result.stdout.strip() if result and result.stdout.strip() else 'unknown'
@@ -165,85 +163,6 @@ def docker_status():
    }


-def swanctl(command):
-    """The entries of a swanctl list command, or None when swanctl cannot be asked.
-
-    The --pretty output has one item per line: "name {" opens a section, "key = [" a list
-    whose items follow one per line, "}" and "]" close them, and "key = value" is a pair
-    whose value may contain spaces. Every "... event {" section at the top holds one
-    connection or SA; each becomes an entry with its name under "name". The closing
-    "... reply {" section is left out. Values stay strings, as swanctl prints them.
-    Output with more closing than opening lines gives None.
-    """
-    result = run('swanctl', command, '--pretty')
-    if result is None or result.returncode != 0:
-        return None
-    events = []
-    stack = []
-    for line in result.stdout.splitlines():
-        line = line.strip()
-        if not line:
-            continue
-        if line in ('}', ']'):
-            if not stack:
-                return None
-            stack.pop()
-        elif not stack:
-            section = {}
-            if line.endswith(' event {'):
-                events.append(section)
-            stack.append(section)
-        elif isinstance(stack[-1], list):
-            stack[-1].append(line)
-        elif line.endswith(' {'):
-            stack[-1][line[:-2]] = section = {}
-            stack.append(section)
-        elif line.endswith(' = ['):
-            stack[-1][line[:-4]] = items = []
-            stack.append(items)
-        else:
-            key, _, value = line.partition(' = ')
-            stack[-1][key] = value
-    return [dict(body, name=name) for event in events for name, body in event.items()]
-
-
-def established(connection):
-    """The number of established IKE SAs of the connection, or None when swanctl cannot be asked."""
-    sas = swanctl('--list-sas')
-    if sas is None:
-        return None
-    return sum(1 for sa in sas if sa['name'] == connection and sa.get('state') == 'ESTABLISHED')
-
-
-def wireguard_peers():
-    """One entry per WireGuard peer, with its handshake age and traffic, or None when wg0 is down."""
-    result = run('wg', 'show', 'wg0', 'dump')
-    if result is None or result.returncode != 0:
-        return None
-    now = int(time.time())
-    peers = []
-    for line in result.stdout.splitlines()[1:]:
-        fields = line.split('\t')
-        if len(fields) < 7:
-            continue
-        handshake = int(fields[4])
-        peers.append({
-            'handshake_seconds_ago': now - handshake if handshake else None,
-            'received_bytes': int(fields[5]),
-            'sent_bytes': int(fields[6]),
-        })
-    return peers
-
-
-def openvpn_clients():
-    """The number of connected OpenVPN clients, from the server's status file, or None when it cannot be read."""
-    try:
-        with open(OPENVPN_STATUS, encoding='utf-8') as handle:
-            return sum(1 for line in handle if line.startswith('CLIENT_LIST,'))
-    except OSError:
-        return None
-
-
 def postgresql_clusters():
    """The state of each PostgreSQL cluster unit (postgresql@<version>-<name>), or {'postgresql': 'no cluster'} without one.

@@ -288,6 +207,26 @@ def collect(state):
    return status


+def shown(status, content, client):
+    """The status document as web.status_content shows it to the client at its address.
+
+    Every content has status, time and client_ip, the client's address, and content, which one it is: basic nothing
+    more; standard adds version, manager_version and services, the number of active units and of units in every
+    other state; full adds the whole status document of collect. Content that is not one of
+    vpnrouter.STATUS_CONTENTS, or not set, is basic.
+    """
+    if content not in vpnrouter.STATUS_CONTENTS:
+        content = 'basic'
+    if content == 'full':
+        return {**status, 'content': content, 'client_ip': client}
+    document = {'status': status['status'], 'content': content, 'time': status['time'], 'client_ip': client}
+    if content == 'standard':
+        active = sum(1 for value in status['units'].values() if value == 'active')
+        document.update(version=status['version'], manager_version=status['manager_version'],
+                        services={'active': active, 'failed': len(status['units']) - active})
+    return document
+
+
 def lines_of(*args):
    """The output lines of a command, or None when it fails."""
    result = run(*args)
@@ -345,13 +284,20 @@ def details(state):


 def text_of(status):
-    """The status for people, as plain text."""
-    lines = ['VPN Router', f'Status: {status["status"]}', f'Version: {status["version"] or "unknown"}', '']
-    lines.append(f'Router Manager: {status["manager_version"] or "not installed"}')
-    lines += [f'{name}: {value}' for name, value in status['units'].items()]
-    docker = status['docker']
-    lines.append('Docker: not installed' if not docker['installed']
-                 else f'Docker: installed, service {docker["service"]}, rules {docker["rules"]}')
+    """The status document of shown for people, as plain text: a header, a blank line, then name: value lines."""
+    lines = ['VPN Router', f'Status: {status["status"]}']
+    if 'version' in status:
+        lines.append(f'Version: {status["version"] or "unknown"}')
+    lines += ['', f'Client IP: {status["client_ip"]}']
+    if 'manager_version' in status:
+        lines.append(f'Router Manager: {status["manager_version"] or "not installed"}')
+    if 'services' in status:
+        lines.append(f'Services: {status["services"]["active"]} active, {status["services"]["failed"]} failed')
+    lines += [f'{name}: {value}' for name, value in status.get('units', {}).items()]
+    if 'docker' in status:
+        docker = status['docker']
+        lines.append('Docker: not installed' if not docker['installed']
+                     else f'Docker: installed, service {docker["service"]}, rules {docker["rules"]}')
    if 'site_to_site' in status:
        value = status['site_to_site']['established']
        lines.append(f'Site to site: {"unknown" if value is None else "established" if value else "not established"}')
@@ -375,11 +321,12 @@ def text_of(status):


 def html_of(status):
-    """The status for a browser, as a page styled with Tailwind CSS."""
+    """The status document of shown for a browser, as a page styled with Tailwind CSS."""
    colour = 'bg-emerald-600 dark:bg-emerald-700' if status['status'] == 'ok' else 'bg-amber-600 dark:bg-amber-700'
-    # Each "name: value" line of the text is a row; indented lines, such as WireGuard peers, are indented here too.
+    version = f', version {status["version"] or "unknown"}' if 'version' in status else ''
+    # Each "name: value" line after the header of the text is a row; indented lines, such as WireGuard peers, are indented here too.
    rows = []
-    for line in text_of(status).splitlines()[4:]:
+    for line in text_of(status).split('\n\n', 1)[1].splitlines():
        if not line:
            continue
        name, _, value = line.partition(': ')
@@ -403,7 +350,7 @@ def html_of(status):
      <div class="overflow-hidden rounded-2xl border border-slate-200 bg-white shadow-lg dark:border-slate-700 dark:bg-slate-800">
        <div class="{colour} px-6 py-4 text-white">
          <h1 class="text-xl font-semibold">VPN Router</h1>
-          <p class="mt-1 text-sm">Status: {escape(status['status'])}, version {escape(status['version'] or 'unknown')}</p>
+          <p class="mt-1 text-sm">Status: {escape(status['status'] + version)}</p>
        </div>
        <div class="px-6 py-4">
          <table class="w-full text-sm"><tbody>{body}</tbody></table>
@@ -421,7 +368,7 @@ def users(state, method, path, body):

      GET    /users                   the users
      POST   /users                   add a user: {"name", "password", "first_name", "last_name", "email"};
-                                      without the last three a Manager-only account
+                                      without the names a Manager-only account
      PUT    /users/<name>            change any of {"first_name", "last_name", "email"}
      PUT    /users/<name>/password   set the password: {"password": ...}
      POST   /users/<name>/disable    lock the user out of OpenVPN
@@ -561,6 +508,22 @@ def account(name, method, path, body):
    return 200, document


+def metrics_history(view):
+    """Answer GET /metrics/history?range=<view> with vpnrouter_metrics.history: the HTTP status and the JSON document.
+
+    view is hour, the default, day, month or year (vpnrouter_metrics.RANGES).
+    """
+    if view not in vpnrouter_metrics.RANGES:
+        return 400, {'error': f'range must be one of {", ".join(vpnrouter_metrics.RANGES)}'}
+    try:
+        with vpnrouter_metrics.database(vpnrouter.load_config()) as connection:
+            return 200, vpnrouter_metrics.history(connection, view)
+    except vpnrouter_metrics.DatabaseError as exc:
+        return 500, {'error': str(exc)}
+    except SystemExit as exc:
+        return 500, {'error': str(exc.code)}
+
+
 def changes_admins(connection, method, parts, body):
    """Whether a /users or /groups request creates, renames to, changes or removes ADMIN_GROUP, or removes a member of it."""
    admins = vpnrouter_users.ADMIN_GROUP
@@ -606,6 +569,9 @@ def auth(path, body):
        cfg = vpnrouter.load_config()
        if path == '/auth':
            vpnrouter_users.login(body.get('name'), body.get('password'), body.get('code'))
+            with vpnrouter_users.session() as connection:
+                if vpnrouter_users.service(vpnrouter_users.entry(connection, body['name'])):
+                    raise vpnrouter_users.Failure('the name, the password or the code is wrong', 5)
            return 200, vpnrouter_auth.issue(cfg, body['name'])
        name = vpnrouter_auth.take(cfg, body.get('refresh_token'))
        if path == '/auth/logout':
@@ -682,7 +648,7 @@ class Handler(BaseHTTPRequestHandler):
        if self.command not in ('GET', 'HEAD'):
            self.close_connection = True
        directory = next((name for name in ('users', 'groups', 'account') if path == f'/{name}' or path.startswith(f'/{name}/')), None)
-        protected = path == '/config' or directory is not None
+        protected = path in ('/config', '/metrics/history') or directory is not None
        signing = path in ('/auth', '/auth/refresh', '/auth/logout')
        state = current() if protected or signing else {}
        claims = self.claims(state['key']) if protected and state['key'] else None
@@ -709,22 +675,27 @@ class Handler(BaseHTTPRequestHandler):
            body = json.dumps({'error': refused[1]}, indent=2).encode() + b'\n'
        elif path == '/config' and self.command in ('GET', 'HEAD'):
            body, kind, code = json.dumps(details(state), indent=2).encode() + b'\n', 'application/json', 200
+        elif path == '/metrics/history' and self.command in ('GET', 'HEAD'):
+            query = urllib.parse.parse_qs(urllib.parse.urlsplit(self.path).query)
+            code, document = metrics_history(query.get('range', ['hour'])[0])
+            body, kind = json.dumps(document).encode() + b'\n', 'application/json'
        elif directory == 'account':
            code, document = account(claims['sub'], self.command, path, payload)
            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
-        elif protected and path != '/config':
+        elif directory is not None:
            code, document = (users if directory == 'users' else groups)(state, self.command, path, payload)
            body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
        elif self.command not in ('GET', 'HEAD'):
            body, kind, code = b'Method not allowed\n', 'text/plain; charset=utf-8', 405
-        elif path == '/status':
-            body, kind, code = json.dumps(self.status(), indent=2).encode() + b'\n', 'application/json', 200
-        elif path == '/':
+        elif path in ('/status', '/'):
+            document = shown(self.status(), section(read_json(CONFIG_FILE), 'web').get('status_content'), self.client())
            agent = self.headers.get('User-Agent', '').lower()
-            if 'curl' in agent or 'wget' in agent:
-                body, kind = text_of(self.status()).encode(), 'text/plain; charset=utf-8'
+            if path == '/status':
+                body, kind = json.dumps(document, indent=2).encode() + b'\n', 'application/json'
+            elif 'curl' in agent or 'wget' in agent:
+                body, kind = text_of(document).encode(), 'text/plain; charset=utf-8'
            else:
-                body, kind = html_of(self.status()).encode(), 'text/html; charset=utf-8'
+                body, kind = html_of(document).encode(), 'text/html; charset=utf-8'
            code = 200
        else:
            body, kind, code = b'Not found\n', 'text/plain; charset=utf-8', 404
@@ -0,0 +1,129 @@
+#!/usr/bin/python3
+"""Show and change the router's configuration, /etc/vpn-router/vpn-router.json.
+
+show prints the file as indented JSON; the file is not changed. set takes a setting as
+section.option, such as web.port, and a value, which it converts to the type the package's
+schema (vpnrouter.SCHEMA) gives the setting: a whole number, true or false, a list of strings
+separated by commas (an empty value is an empty list), or a string. The configuration with the
+new value is checked as vpn-router-setup checks it, and only then written, indented, with mode
+0600; vpn-router-setup applies it at its next run, which set reminds of. A failure is a message
+on standard error; the exit status is 2 for an invalid request and 1 for any other failure.
+-h or --help shows the options.
+
+  vpn-config-edit show
+  vpn-config-edit set SECTION.OPTION VALUE
+"""
+
+import argparse
+import json
+import os
+import sys
+import tempfile
+
+sys.path.insert(0, '/usr/lib/vpn-router')
+
+import vpnrouter
+
+
+class Failure(Exception):
+    """A request that cannot be done; status is 2 invalid, 1 other."""
+
+    def __init__(self, message, status=1):
+        super().__init__(message)
+        self.status = status
+
+
+class Parser(argparse.ArgumentParser):
+    """An argument parser whose errors are Failures with status 2."""
+
+    def error(self, message):
+        raise Failure(f'{message}; see {self.prog} --help', 2)
+
+
+def read():
+    """The settings in the configuration file, without the defaults; {} when the file does not exist."""
+    try:
+        data = json.loads(vpnrouter.CONFIG_FILE.read_text(encoding='utf-8'))
+    except FileNotFoundError:
+        return {}
+    except ValueError as exc:
+        raise Failure(f'cannot parse {vpnrouter.CONFIG_FILE}: {exc}')
+    if not isinstance(data, dict) or not all(isinstance(options, dict) for options in data.values()):
+        raise Failure(f'cannot parse {vpnrouter.CONFIG_FILE}: it is not an object of sections')
+    return data
+
+
+def converted(key, text):
+    """The value of text for the setting key, section.option, of the type the schema gives it."""
+    section, _, option = key.partition('.')
+    if section not in vpnrouter.SCHEMA or option not in vpnrouter.SCHEMA[section]:
+        raise Failure(f'{key}: unknown setting; settings are section.option, such as web.port', 2)
+    kind = type(vpnrouter.SCHEMA[section][option])
+    if kind is bool:
+        if text not in ('true', 'false'):
+            raise Failure(f'{key} takes true or false', 2)
+        return text == 'true'
+    if kind is int:
+        try:
+            return int(text)
+        except ValueError:
+            raise Failure(f'{key} takes a whole number', 2)
+    if kind is list:
+        return [item.strip() for item in text.split(',') if item.strip()]
+    return text
+
+
+def write(data):
+    """Write the settings, indented, with mode 0600, replacing the file in one step."""
+    directory = vpnrouter.CONFIG_FILE.parent
+    descriptor, name = tempfile.mkstemp(dir=directory, prefix='.vpn-router.json.')
+    try:
+        with os.fdopen(descriptor, 'w', encoding='utf-8') as handle:
+            handle.write(json.dumps(data, indent=2) + '\n')
+        os.chmod(name, 0o600)
+        os.replace(name, vpnrouter.CONFIG_FILE)
+    except OSError:
+        os.unlink(name)
+        raise
+
+
+def main(argv):
+    try:
+        parser = Parser(prog='vpn-config-edit', description='Show and change the router configuration.')
+        commands = parser.add_subparsers(dest='command', required=True, parser_class=Parser)
+        commands.add_parser('show', help='print the configuration as indented JSON')
+        setter = commands.add_parser('set', help='set a setting and write the configuration')
+        setter.add_argument('key', metavar='SECTION.OPTION', help='the setting, such as web.port')
+        setter.add_argument('value', metavar='VALUE', help='its value; a list separated by commas')
+        options = parser.parse_args(argv)
+
+        data = read()
+        if options.command == 'show':
+            print(json.dumps(data, indent=2))
+            return 0
+
+        section, _, option = options.key.partition('.')
+        value = converted(options.key, options.value)
+        data.setdefault(section, {})[option] = value
+        # The configuration as vpn-router-setup reads it: the defaults with the file's settings.
+        candidate = {name: dict(defaults) for name, defaults in vpnrouter.SCHEMA.items()}
+        for name, settings in data.items():
+            candidate.setdefault(name, {}).update(settings)
+        try:
+            vpnrouter.validate(candidate)
+        except vpnrouter.ConfigError as exc:
+            raise Failure(str(exc), 2)
+        write(data)
+    except Failure as failure:
+        print(f'vpn-config-edit: {failure}', file=sys.stderr)
+        return failure.status
+    except OSError as exc:
+        print(f'vpn-config-edit: {exc}', file=sys.stderr)
+        return 1
+    print(f'{options.key} set to {json.dumps(value)} in {vpnrouter.CONFIG_FILE}.')
+    print('Apply it with: systemctl restart vpn-router-setup')
+    return 0
+
+
+if __name__ == '__main__':
+    sys.exit(main(sys.argv[1:]))
@@ -115,7 +115,7 @@ def text_of(answer):
    if not users:
        return 'no users'
    head = ('USER', 'KIND', 'STATE', 'CERTIFICATE', 'OTP', 'FIRST NAME', 'LAST NAME', 'E-MAIL')
-    rows = [(user['name'], 'manager' if user['manager_only'] else 'vpn',
+    rows = [(user['name'], 'service' if user['service'] else 'manager' if user['manager_only'] else 'vpn',
             'disabled' if not user['enabled'] else 'locked' if user['locked'] else 'enabled',
             'issued' if user['certificate'] else 'missing',
             'enrolled' if user['otp'] else '-', user['first_name'] or '-', user['last_name'] or '-', user['email'] or '-')
@@ -45,8 +45,31 @@
  },
  "web": {
    "enabled": true,
+    "listen": "both",
    "port": 7081,
    "database": "",
-    "trusted_proxies": []
+    "trusted_proxies": [],
+    "status_content": "basic"
+  },
+  "https": {
+    "enabled": true,
+    "email": "",
+    "web_port": 7444,
+    "manager_port": 7443
+  },
+  "metrics": {
+    "enabled": true,
+    "listen": "internal",
+    "port": 9464,
+    "https_port": 9465,
+    "service_account": "metrics",
+    "otlp_endpoint": "",
+    "otlp_username": "",
+    "otlp_password": "",
+    "keep_details": "24 hours",
+    "keep_hourly": "1 month",
+    "keep_daily": "3 months",
+    "keep_monthly": "1 year",
+    "keep_yearly": "10 years"
  }
 }
@@ -0,0 +1,22 @@
+# Written by vpn-router-setup from /etc/vpn-router/vpn-router.json; edits are overwritten.
+{
+	auto_https disable_redirects
+{%- if https_email %}
+	email {{ https_email }}
+{%- endif %}
+}
+{% if web_enabled %}
+{{ local_fqdn }}:{{ https_web_port }} {
+	reverse_proxy {{ loopback }}:{{ web_port }}
+}
+{% endif %}
+{%- if manager_port %}
+{{ local_fqdn }}:{{ https_manager_port }} {
+	reverse_proxy {{ loopback }}:{{ manager_port }}
+}
+{% endif %}
+{%- if metrics_enabled %}
+{{ local_fqdn }}:{{ metrics_https_port }} {
+	reverse_proxy {{ loopback }}:{{ metrics_port }}
+}
+{% endif %}
Author	SHA1	Message	Date
slawek	38151bf5be	feature: the router keeps its metrics in PostgreSQL, serves them for an OpenTelemetry Collector and pushes them over OTLP. Release / release (push) Successful in 14s Details	2026-10-25 14:57:47 +01:00
slawek	83c1c50d8d	feature: vpn-config-edit shows and changes the router's configuration. Release / release (push) Successful in 19s Details	2026-10-25 13:29:12 +01:00
slawek	650896131d	fix: web.status_content is basic by default. Release / release (push) Successful in 19s Details	2026-10-25 13:09:57 +01:00
slawek	dbc2046e24	feature: the status page shows the Client IP, and web.status_content sets how much it shows. Release / release (push) Successful in 12s Details	2026-10-25 13:08:08 +01:00
slawek	45d73abe7b	feature: Caddy serves the status page and the Router Manager over HTTPS with a certificate from Let's Encrypt. Release / release (push) Successful in 23s Details	2026-10-25 12:25:57 +01:00
slawek	993a7a9fa9	fix: the web service listens on the internal address, the external address or both. Release / release (push) Successful in 25s Details	2026-10-25 11:37:43 +01:00