feature: every write of an instance's variable files is kept as a revision with the schema version of their layout and the application that wrote them.

ADR.md

@@ -76,3 +76,84 @@ Consequences: Without the key no secret can be saved or used, and a changed key
 secrets unusable until they are entered again. SHA-256 does not slow down guessing a weak key, so
 the key has to be long and random. Anyone who reaches the routes can replace credentials, as the
 applications have no authentication.
+
+## ADR-4: The key of a credential store is a path, so related stores share one object
+
+Status: Accepted
+
+Context: sql-query-webui keeps connection profiles of PostgreSQL and of SQL Server. As stores of
+top-level keys, the keys have to carry the kind in their names, and a key such as `connections`
+does not say which kind it holds once there are several.
+
+Decision: The key of a store is a key of `config.json` or a path of keys separated by dots, such
+as `connections.pg` and `connections.mssql`. The store reads the list at the path, reports its
+problems by `<path>.<index>.<field>`, and a write sets the list at the path, creating the objects
+of the path that are missing, or are not objects, and keeping their other keys, so stores of one
+object can be written one after the other. The kind stays the store's, not a field of an entry
+(ADR-3).
+
+Consequences: A key of `config.json` holding a dot cannot be the key of a store. A single key
+reads and writes as before, so applications of one-key stores need no change. The application
+checks the object of a path, such as the keys it allows in it, itself.
+
+## ADR-5: Terraform modules, instances and their variable files are tables shared through the toolkit
+
+Status: Accepted
+
+Context: Cloud Platform deploys many instances of many Terraform modules, and each module's
+configurator, a separate application, edits the variables of its instances. Both have to read
+and write the same modules, instances and variable files, with the same versions, so that a
+write from an outdated read is refused whichever application made it.
+
+Decision: The toolkit holds the tables and their functions and procedures,
+`server/sql/tfvars_store.sql`, and `createTfvarsStore`, which both applications use with their own
+`pg` pool. An instance names the schema of its state, unique among instances. A variable file is
+a row of its instance, its object as `jsonb` with the one it replaced. The version of an
+instance's files is the name and the SHA-256 of each file's text, `tfvarsText` of its object, in
+name order; a write locks the table, compares the version and writes in one transaction. A change
+the tables refuse is an `HttpError` with the status the routes answer. `pg` is an optional peer
+dependency, as the applications that do not use the store do not need it.
+
+Consequences: Every application of the store works on the same rows and refuses the same
+conflicts, and changes of the tables reach them with a release of the toolkit. The objects' keys
+are in `jsonb`'s order. The store is tested against a real PostgreSQL server, which the release
+workflow does not have, so `npm test` runs on the developer's machine.
+
+## ADR-6: A fourth entry point, /shared, exports the shared types and constants
+
+Status: Accepted
+
+Context: An application keeps the types of its API in one file that its server and its web
+application both import. When those types name types of the toolkit, such as `TfModule`, the file
+must import them from an entry point both sides can resolve: `/server` brings Fastify and `pg`
+into the web application's type check, `/web` brings React and MUI into the server's.
+
+Decision: `shared/index.ts` is the entry point `/shared`, built and exported like the other three.
+It exports the types and constants of `shared/`, the credential types and the types and name
+patterns of the tfvars store, and no code that needs a peer dependency. `/server` and `/web` keep
+exporting them too.
+
+Consequences: An application's shared API types import from `/shared` without the code of either
+side. A type added to `shared/` is exported from `/shared` as well as from the side that uses it.
+
+## ADR-7: Every write of an instance's variable files is a revision with its schema and producer
+
+Status: Accepted
+
+Context: A configurator changes the layout of the variable files it writes from one version to
+the next, and Cloud Platform has to tell whether an instance's files are of the layout its
+module's configurator writes before it runs Terraform with them. The files written earlier have
+to stay available, to restore or compare them.
+
+Decision: `tf_variable_revisions` holds every write of an instance's files: all files after the
+write, the schema version of their layout as the writer gives it, null when it does not know it,
+the producer, the writing application with its version, and the time. `write` and `remove` take
+the schema and the producer and record the revision in the transaction of the change, under the
+lock of the files; a write of no file records none. The current files stay in `tf_variable_files`,
+so reading them and their version is unchanged. Revisions are kept until removed by hand with
+SQL. Files without revisions are recorded as revision 1 of an unknown producer and schema when the
+store is first used.
+
+Consequences: The schema of an instance's files is the schema of its newest revision; files
+imported without a schema, or written before revisions, have none until a configurator writes
+them. Revisions grow with every write; the README describes the SQL that removes them.

CHANGELOG.md

@@ -1,5 +1,66 @@
 # Changelog
 
+## 0.7.0
+
+feature: every write of an instance's variable files is kept as a revision with the schema version
+of their layout and the application that wrote them.
+
+- `tf_variable_revisions` keeps all files of an instance after each write, with `schema`, null when
+  not known, `producer` and `saved`; revisions are numbered from 1 for each instance and kept until
+  removed by hand.
+- `write(version, contents, meta)` and `remove(version, name, meta)` take `meta`, `{ schema,
+  producer }`, and record the revision in the same transaction; a write of no file records none.
+- `read()` answers the newest revision as `revision`; `revisions()` lists them, newest first, and
+  `revision(n)` answers one with its files. `TfvarsRevision` is exported from `/server` and
+  `/shared`.
+- The files of an instance without revisions become its revision 1, of the producer `unknown` and
+  no schema.
+- The README describes the SQL that purges some or all revisions of a module's instance.
+
+## 0.6.0-2
+
+fix: release.mjs reads a summary wrapped over several lines.
+
+- `release.mjs` takes the summary of the newest entry as the paragraph after its heading and joins
+  its lines with single spaces into the commit message.
+
+## 0.6.0
+
+feature: RowDialog validates a row as part of a larger value, such as a whole document with the row put in.
+
+- `RowDialog` takes `body`, the value posted to `validatePath` for the row, and `select`, the
+  row's problems by field and message taken from the answer.
+- `useValidation` and `RowDialog` take an answer of any shape.
+
+## 0.5.0
+
+feature: the entry point /shared exports the types and constants a server and its web application share.
+
+- `@koszewscy/sk-react-toolkit/shared` exports the credential types, `TfModule`, `TfInstance`,
+  `TfvarsFileStatus` and the name patterns of the tfvars store, for the API types of an
+  application imported by both its server and its web application.
+
+## 0.4.0
+
+feature: the tfvars store keeps Terraform modules, their instances and the instances' variable files in PostgreSQL.
+
+- `createTfvarsStore(pool)`: the tables `tf_modules`, `tf_instances` and `tf_variable_files`,
+  created at the first use, with `modules` (`list`, `put`, `delete`), `instances` (`list`,
+  `create`, `delete`) and `variables(module, instance)` (`read`, `write`, `remove`), whose writes
+  take the version read and answer `false` when the files changed since.
+- `versionOf`, `tfvarsText`, and the types `TfModule`, `TfInstance` and `TfvarsFileStatus` with
+  the patterns of their names, also exported from `/web`.
+- `pg` is an optional peer dependency, for the store.
+- `npm test` tests the store against a scratch database of the server the `PG*` variables name.
+
+## 0.3.0
+
+feature: the key of a credential store may be a path of keys, so stores of several kinds share one object of config.json.
+
+- `CredentialStore.key` is a key of `config.json` or a path of keys separated by dots, such as
+  `connections.pg`; read, validate, write and `credentialValues` use the list at that path, and a
+  write creates the objects of the path that are missing and keeps their other keys.
+
 ## 0.2.1
 
 fix: a credential store holds credentials of one kind, without a kind field in its entries, and the dialog edits several stores in tabs.

README.md

@@ -8,7 +8,7 @@ source: Node 26 runs the server helpers, and the application's Vite build compil
 
 The package is `@koszewscy/sk-react-toolkit`, published to the npm registry of Gitea,
 `https://gitea.koszewscy.waw.pl/api/packages/koszewscy/npm/`. An application depends on a
-published version and imports `@koszewscy/sk-react-toolkit/server`, `/web` and `/vite`. Its
+published version and imports `@koszewscy/sk-react-toolkit/server`, `/shared`, `/web` and `/vite`. Its
 `.npmrc` names the registry of the scope:
 
 ```ini
@@ -64,6 +64,14 @@ code; `vite` for the Vite helpers.
 | `readJsonObject(path, options)` | a JSON object file and its version, the SHA-256 of its bytes; optionally `{}` for a missing file |
 | `encryptionKey()`, `encrypt(text, key)`, `decrypt(encrypted, key)` | the key of the secrets and AES-256-GCM encryption; see [Credential store](#credential-store) |
 | `CredentialStore`, `credentialProblems`, `credentialValues`, `registerCredentialRoutes`, `POSTGRESQL_KIND` | the credential store; see [Credential store](#credential-store) |
+| `createTfvarsStore`, `versionOf`, `tfvarsText`, `TfModule`, `TfInstance`, `TfvarsFileStatus`, `TF_NAME_PATTERN`, `TFVARS_FILE_PATTERN`, `STATE_SCHEMA_PATTERN` | the Terraform modules, their instances and their variable files in PostgreSQL; see [Tfvars store](#tfvars-store) |
+
+## sk-react-toolkit/shared
+
+The types and constants of `/server` and `/web` that a server and its web application share, for
+API types imported by both, without the code of either: `CredentialField`, `CredentialKind`,
+`CredentialProfile`, `CredentialsDocument`, `TfModule`, `TfInstance`, `TfvarsFileStatus`,
+`TF_NAME_PATTERN`, `TFVARS_FILE_PATTERN` and `STATE_SCHEMA_PATTERN`.
 
 ## sk-react-toolkit/web
 
@@ -76,9 +84,10 @@ code; `vite` for the Vite helpers.
 | `ThemeMenu` | the button cycling light, dark and system theme |
 | `SwitcherMenu`, `SwitcherItem` | a button naming the item chosen, whose menu chooses another, such as a page or a connection |
 | `TextInput` | a text field with clear and show/hide buttons |
-| `RowDialog`, `useValidation` | a dialog that edits a value validated by the server as it changes, and the validation hook |
+| `RowDialog`, `useValidation` | a dialog that edits a value validated by the server as it changes, and the validation hook; with `body` and `select` the dialog posts another value, such as a whole document with the row put in, and takes the row's problems from the answer |
 | `createBrowserSettings(keys, event)` | switches kept in localStorage and followed across tabs |
 | `CredentialsButton` | the dialog of a credential store; see [Credential store](#credential-store) |
+| `TfModule`, `TfInstance`, `TfvarsFileStatus`, `TF_NAME_PATTERN`, `TFVARS_FILE_PATTERN`, `STATE_SCHEMA_PATTERN` | the types and name patterns of the [Tfvars store](#tfvars-store) |
 
 ## sk-react-toolkit/vite
 
@@ -124,7 +133,19 @@ saved or used; a secret encrypted with another key cannot be decrypted and has t
 again.
 
 `CredentialStore` describes a store: the path of `config.json`, the key, the kind, the reserved
-names and whether a missing `config.json` reads as `{}`.
+names and whether a missing `config.json` reads as `{}`. The key is a key of `config.json` or a
+path of keys separated by dots, such as `connections.pg`, for a list in nested objects; a write
+creates the objects of the path that are missing and keeps their other keys, so stores of several
+kinds can share one object:
+
+```json
+{
+  "connections": {
+    "pg": [{ "name": "state", "host": "db.example.com", "port": 5432, "...": "..." }],
+    "mssql": [{ "name": "warehouse", "host": "sql.example.com", "port": 1433, "...": "..." }]
+  }
+}
+```
 
 - `credentialProblems(value, store)`: the problems of the key's value by `<key>.<index>.<field>`,
   for the application's own check of `config.json`.
@@ -147,11 +168,75 @@ them; a tab with a problem has a red label. A secret shows only whether it is ke
 replaces it and Remove drops it. Save writes each store that changed, each write with the version
 the previous one answers.
 
+## Tfvars store
+
+The tfvars store keeps Terraform modules, their instances and the variable files of each
+instance in PostgreSQL, for Cloud Platform, which deploys the instances, and the configurators,
+which edit their variables. `createTfvarsStore(pool)` takes a `pg` pool and applies
+`server/sql/tfvars_store.sql` at its first use, in the schema of the connection's search path:
+
+| Table | Rows |
+| --- | --- |
+| `tf_modules` | `name`, `root`, the folder of the Terraform code, `description` and `configurator_url` |
+| `tf_instances` | `module`, `name` and `state_schema`, the schema of the instance's state in the pg backend, unique, and `created` |
+| `tf_variable_files` | `module`, `instance`, `name` (`*.tfvars.json`), `content` and `previous`, the object it replaced, as `jsonb`, and `updated` |
+| `tf_variable_revisions` | `module`, `instance`, `revision`, numbered from 1 for each instance, `files`, all its files after a write as a `jsonb` object by name, `schema`, the schema version of their layout or null, `producer` and `saved` |
+
+Names of modules and instances are `TF_NAME_PATTERN`, of variable files `TFVARS_FILE_PATTERN`,
+of state schemas `STATE_SCHEMA_PATTERN`.
+
+- `modules.list()`, `modules.put(module)`, which creates or changes, and `modules.delete(name)`.
+- `instances.list(module)`, `instances.create(module, name, stateSchema)` and
+  `instances.delete(module, name)`, which deletes its variable files too.
+- `variables(module, instance)`: `read()` answers the files, their sizes and times, the version,
+  `versionOf` the files, the name and the SHA-256 of each in name order, and the newest revision.
+  `write(version, contents, meta)` writes files given by name as JSON text and `remove(version,
+  name, meta)` deletes one; both lock the table, compare the version, change and record all files
+  as the next revision with `meta`, `{ schema, producer }`, in one transaction, and answer
+  `false`, changing nothing, when the files changed since the version. A write of no file records
+  no revision. `revisions()` lists the revisions, newest first, without their files, and
+  `revision(n)` answers one with its files, or `null`.
+
+Every revision is kept. The files of an instance without any revision, as those written before
+revisions existed, are recorded as its revision 1, of the producer `unknown` and no schema, when
+the store is first used.
+
+### Purging revisions
+
+Revisions are removed by hand, with `psql` connected to the database of the store as the owner of
+its tables, in the schema the applications use (`SET search_path TO <schema>;` when it is not the
+default). Each statement removes the revisions of one instance, here `router`/`platform`:
+
+```sql
+-- All revisions but the newest.
+DELETE FROM tf_variable_revisions
+WHERE module = 'router' AND instance = 'platform'
+  AND revision < (SELECT max(revision) FROM tf_variable_revisions WHERE module = 'router' AND instance = 'platform');
+
+-- The revisions before revision 10.
+DELETE FROM tf_variable_revisions WHERE module = 'router' AND instance = 'platform' AND revision < 10;
+
+-- All revisions of the instance.
+DELETE FROM tf_variable_revisions WHERE module = 'router' AND instance = 'platform';
+```
+
+Leaving out `AND instance = ...` applies a statement to every instance of the module. The next
+write numbers its revision after the newest one left. An instance whose revisions are all removed
+gets its current files back as revision 1, of the producer `unknown` and no schema, when the store
+is next first used, so its schema is unknown until the next write by its configurator.
+
+A change the tables refuse throws `HttpError`: 409 for a name or a state schema in use and for a
+module that has instances, 404 for a module or an instance that does not exist, 400 for a name or
+a content the tables do not accept. The content of a file is the object as `jsonb` keeps it,
+written by `tfvarsText`, so the order of object keys is `jsonb`'s; arrays keep theirs.
+
 ## Development
 
 `npm install` installs the peer dependencies as development dependencies; `npm run typecheck`
-and `npm run lint` check the code. `npm run build` (`build.mjs`) builds the published package in
+and `npm run lint` check the code. `npm test` tests the tfvars store in a scratch database it
-`dist/`: the code compiled to JavaScript with its declarations, README.md, CHANGELOG.md and a
+creates and drops on the PostgreSQL server the `PG*` variables name, connected to through the
+database `postgres`. `npm run build` (`build.mjs`) builds the published package in
+`dist/`: the code compiled to JavaScript with its declarations, the SQL of the server, README.md, CHANGELOG.md and a
 `package.json` whose exports name the compiled files.
 
 ## Releases

build.mjs

@@ -1,15 +1,16 @@
 #!/usr/bin/env node
 
 // Builds the published package in dist/: the toolkit compiled to JavaScript with its declarations, the declaration of
-// the font plugin's virtual module, README.md, CHANGELOG.md and a package.json whose exports name the compiled files.
+// the font plugin's virtual module, the SQL of the server, README.md, CHANGELOG.md and a package.json whose exports
+// name the compiled files.
 
 import { spawnSync } from 'node:child_process';
-import { copyFileSync, readdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
+import { copyFileSync, cpSync, readdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import { join } from 'node:path';
 
 const ROOT = import.meta.dirname;
 const DIST = join(ROOT, 'dist');
-const ENTRIES = ['server', 'web', 'vite'];
+const ENTRIES = ['server', 'shared', 'web', 'vite'];
 
 function fail(message) {
   console.error(`build: ${message}`);
@@ -22,7 +23,7 @@ if (tsc.error) fail(`tsc: ${tsc.error.message}; run npm ci first`);
 if (tsc.status !== 0) process.exit(tsc.status ?? 1);
 
 // The declarations import the other declarations by their .js names, as the compiled JavaScript does.
-for (const entry of [...ENTRIES, 'shared']) {
+for (const entry of ENTRIES) {
   for (const file of readdirSync(join(DIST, entry)).filter((name) => name.endsWith('.d.ts'))) {
     const path = join(DIST, entry, file);
     writeFileSync(path, readFileSync(path, 'utf8').replace(/(from\s+|import\s+)(['"])(\.{1,2}\/[^'"]+)\.tsx?\2/g, '$1$2$3.js$2'));
@@ -34,6 +35,9 @@ copyFileSync(join(ROOT, 'web', 'virtual-font.d.ts'), join(DIST, 'web', 'virtual-
 const renderApp = join(DIST, 'web', 'renderApp.d.ts');
 writeFileSync(renderApp, `/// <reference path="./virtual-font.d.ts" />\n${readFileSync(renderApp, 'utf8')}`);
 
+// The tfvars store reads its SQL next to the compiled module.
+cpSync(join(ROOT, 'server', 'sql'), join(DIST, 'server', 'sql'), { recursive: true });
+
 for (const file of ['README.md', 'CHANGELOG.md']) copyFileSync(join(ROOT, file), join(DIST, file));
 
 const source = JSON.parse(readFileSync(join(ROOT, 'package.json'), 'utf8'));

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "@koszewscy/sk-react-toolkit",
-  "version": "0.2.1",
+  "version": "0.7.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "@koszewscy/sk-react-toolkit",
-      "version": "0.2.1",
+      "version": "0.7.0",
       "devDependencies": {
         "@emotion/react": "^11.14.0",
         "@emotion/styled": "^11.14.1",
@@ -14,10 +14,12 @@
         "@mui/icons-material": "^9.5.0",
         "@mui/material": "^9.5.0",
         "@types/node": "^26.6.5",
+        "@types/pg": "^8.23.1",
         "@types/react": "^19.3.0",
         "@types/react-dom": "^19.3.0",
         "fastify": "^5.12.7",
         "oxlint": "^1.89.0",
+        "pg": "^8.23.1",
         "react": "^19.3.1",
         "react-dom": "^19.3.1",
         "typescript": "^7.0.2",
@@ -33,6 +35,7 @@
         "@mui/icons-material": "^9.5.0",
         "@mui/material": "^9.5.0",
         "fastify": "^5.12.7",
+        "pg": "^8.23.1",
         "react": "^19.3.1",
         "react-dom": "^19.3.1",
         "vite": "^8.3.5"
@@ -56,6 +59,9 @@
         "fastify": {
           "optional": true
         },
+        "pg": {
+          "optional": true
+        },
         "react": {
           "optional": true
         },
@@ -1539,6 +1545,18 @@
       "dev": true,
       "license": "MIT"
     },
+    "node_modules/@types/pg": {
+      "version": "8.23.1",
+      "resolved": "https://registry.npmjs.org/@types/pg/-/pg-8.23.1.tgz",
+      "integrity": "sha512-fKVHpikPdg4GKks3JuLEhvwSyvwzF23hnabPy6DD8ljVbC7+6J5dQzdv4arV6jqq57djnMgs1HKBxX4P8aBI3A==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "@types/node": "*",
+        "pg-protocol": "*",
+        "pg-types": "^2.2.0"
+      }
+    },
     "node_modules/@types/prop-types": {
       "version": "15.7.15",
       "resolved": "https://registry.npmjs.org/@types/prop-types/-/prop-types-15.7.15.tgz",
@@ -3131,6 +3149,103 @@
         "node": ">=8"
       }
     },
+    "node_modules/pg": {
+      "version": "8.23.1",
+      "resolved": "https://registry.npmjs.org/pg/-/pg-8.23.1.tgz",
+      "integrity": "sha512-aL96AHANtWjPLDOLqnhx+ngp9+UK7ETEU8VJrDCGvsSSi/mGLcWYsS6Herg7lmaBJe4uwrfqsa7gTEFaSizDoQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "pg-connection-string": "^2.14.1",
+        "pg-pool": "^3.14.0",
+        "pg-protocol": "^1.16.1",
+        "pg-types": "2.2.0",
+        "pgpass": "1.0.5"
+      },
+      "engines": {
+        "node": ">= 16.0.0"
+      },
+      "optionalDependencies": {
+        "pg-cloudflare": "^1.4.1"
+      },
+      "peerDependencies": {
+        "pg-native": ">=3.0.1"
+      },
+      "peerDependenciesMeta": {
+        "pg-native": {
+          "optional": true
+        }
+      }
+    },
+    "node_modules/pg-cloudflare": {
+      "version": "1.4.1",
+      "resolved": "https://registry.npmjs.org/pg-cloudflare/-/pg-cloudflare-1.4.1.tgz",
+      "integrity": "sha512-6PQbsFWZcp9EmJEwy5cGQ2La+AMWpP46lgbb8X+U/XsHIUweYDNCpeuKck5RxL2MdVFi7krbbEi5nX4Zh7JhrQ==",
+      "dev": true,
+      "license": "MIT",
+      "optional": true
+    },
+    "node_modules/pg-connection-string": {
+      "version": "2.14.1",
+      "resolved": "https://registry.npmjs.org/pg-connection-string/-/pg-connection-string-2.14.1.tgz",
+      "integrity": "sha512-qR3kGNPBLpCNtz0evbKA0Y/MRFXwSSdT+pTJvYp/bXTcReZbvX1kzF0IyTc1QnxqF7AZbOeBhNL8R5mYQZV/MA==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/pg-int8": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/pg-int8/-/pg-int8-1.0.1.tgz",
+      "integrity": "sha512-WCtabS6t3c8SkpDBUlb1kjOs7l66xsGdKpIPZsg4wR+B3+u9UAum2odSsF9tnvxg80h4ZxLWMy4pRjOsFIqQpw==",
+      "dev": true,
+      "license": "ISC",
+      "engines": {
+        "node": ">=4.0.0"
+      }
+    },
+    "node_modules/pg-pool": {
+      "version": "3.14.0",
+      "resolved": "https://registry.npmjs.org/pg-pool/-/pg-pool-3.14.0.tgz",
+      "integrity": "sha512-gKtPkFdQPU3DksooVLi9LsjZxrsBUZIpa+7aVx+LV5pNh0KzP4Zleud2po+ConrxbuXGBJ6Hfer6hdgpIBpBaw==",
+      "dev": true,
+      "license": "MIT",
+      "peerDependencies": {
+        "pg": ">=8.0"
+      }
+    },
+    "node_modules/pg-protocol": {
+      "version": "1.16.1",
+      "resolved": "https://registry.npmjs.org/pg-protocol/-/pg-protocol-1.16.1.tgz",
+      "integrity": "sha512-p9VOFMiHB/ZbJATetbg+99PxssTVSQRnyuPSQ67mN1+1KBOjZaZ83ZQzltnxPhJwSsC3nwVjJ10DVJlerbFzLg==",
+      "dev": true,
+      "license": "MIT"
+    },
+    "node_modules/pg-types": {
+      "version": "2.2.0",
+      "resolved": "https://registry.npmjs.org/pg-types/-/pg-types-2.2.0.tgz",
+      "integrity": "sha512-qTAAlrEsl8s4OiEQY69wDvcMIdQN6wdz5ojQiOy6YRMuynxenON0O5oCpJI6lshc6scgAY8qvJ2On/p+CXY0GA==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "pg-int8": "1.0.1",
+        "postgres-array": "~2.0.0",
+        "postgres-bytea": "~1.0.0",
+        "postgres-date": "~1.0.4",
+        "postgres-interval": "^1.1.0"
+      },
+      "engines": {
+        "node": ">=4"
+      }
+    },
+    "node_modules/pgpass": {
+      "version": "1.0.5",
+      "resolved": "https://registry.npmjs.org/pgpass/-/pgpass-1.0.5.tgz",
+      "integrity": "sha512-FdW9r/jQZhSeohs1Z3sI1yxFQNFvMcnmfuj4WBMUTxOrAyLMaTcE1aAMBiTlbMNaXvBCQuVi0R7hd8udDSP7ug==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "split2": "^4.1.0"
+      }
+    },
     "node_modules/picocolors": {
       "version": "1.1.1",
       "resolved": "https://registry.npmjs.org/picocolors/-/picocolors-1.1.1.tgz",
@@ -3220,6 +3335,49 @@
         "node": "^10 || ^12 || >=14"
       }
     },
+    "node_modules/postgres-array": {
+      "version": "2.0.0",
+      "resolved": "https://registry.npmjs.org/postgres-array/-/postgres-array-2.0.0.tgz",
+      "integrity": "sha512-VpZrUqU5A69eQyW2c5CA1jtLecCsN2U/bD6VilrFDWq5+5UIEVO7nazS3TEcHf1zuPYO/sqGvUvW62g86RXZuA==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=4"
+      }
+    },
+    "node_modules/postgres-bytea": {
+      "version": "1.0.1",
+      "resolved": "https://registry.npmjs.org/postgres-bytea/-/postgres-bytea-1.0.1.tgz",
+      "integrity": "sha512-5+5HqXnsZPE65IJZSMkZtURARZelel2oXUEO8rH83VS/hxH5vv1uHquPg5wZs8yMAfdv971IU+kcPUczi7NVBQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/postgres-date": {
+      "version": "1.0.7",
+      "resolved": "https://registry.npmjs.org/postgres-date/-/postgres-date-1.0.7.tgz",
+      "integrity": "sha512-suDmjLVQg78nMK2UZ454hAG+OAW+HQPZ6n++TNDUX+L0+uUlLywnoxJKDou51Zm+zTCjrCl0Nq6J9C5hP9vK/Q==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
+    "node_modules/postgres-interval": {
+      "version": "1.2.0",
+      "resolved": "https://registry.npmjs.org/postgres-interval/-/postgres-interval-1.2.0.tgz",
+      "integrity": "sha512-9ZhXKM/rw350N1ovuWHbGxnGh/SNJ4cnxHiM0rxE4VN41wsg8P8zWn9hv/buK00RP4WvlOyr/RBDiptyxVbkZQ==",
+      "dev": true,
+      "license": "MIT",
+      "dependencies": {
+        "xtend": "^4.0.0"
+      },
+      "engines": {
+        "node": ">=0.10.0"
+      }
+    },
     "node_modules/process-warning": {
       "version": "5.1.1",
       "resolved": "https://registry.npmjs.org/process-warning/-/process-warning-5.1.1.tgz",
@@ -3744,6 +3902,16 @@
           "optional": true
         }
       }
+    },
+    "node_modules/xtend": {
+      "version": "4.0.2",
+      "resolved": "https://registry.npmjs.org/xtend/-/xtend-4.0.2.tgz",
+      "integrity": "sha512-LKYU1iAXJXUgAXn9URjiu+MWhyUXHsvfp7mcuYm9dSUKK0/CjtrUwFAxD82/mCWbtLsGjFIad0wIsod4zrTAEQ==",
+      "dev": true,
+      "license": "MIT",
+      "engines": {
+        "node": ">=0.4"
+      }
     }
   }
 }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@koszewscy/sk-react-toolkit",
-  "version": "0.2.1",
+  "version": "0.7.0",
   "description": "Shared code of the React and Fastify web applications: web components, server helpers and the Vite font plugin.",
   "private": true,
   "type": "module",
@@ -13,12 +13,14 @@
   },
   "exports": {
     "./server": "./server/index.ts",
+    "./shared": "./shared/index.ts",
     "./web": "./web/index.ts",
     "./vite": "./vite/index.ts"
   },
   "scripts": {
     "typecheck": "tsc -p tsconfig.json",
     "lint": "oxlint",
+    "test": "node --test server/tfvarsStore.test.ts",
     "build": "node build.mjs"
   },
   "peerDependencies": {
@@ -28,6 +30,7 @@
     "@mui/icons-material": "^9.5.0",
     "@mui/material": "^9.5.0",
     "fastify": "^5.12.7",
+    "pg": "^8.23.1",
     "react": "^19.3.1",
     "react-dom": "^19.3.1",
     "vite": "^8.3.5"
@@ -35,6 +38,7 @@
   "peerDependenciesMeta": {
     "@fastify/static": { "optional": true },
     "fastify": { "optional": true },
+    "pg": { "optional": true },
     "vite": { "optional": true },
     "@emotion/react": { "optional": true },
     "@emotion/styled": { "optional": true },
@@ -50,10 +54,12 @@
     "@mui/icons-material": "^9.5.0",
     "@mui/material": "^9.5.0",
     "@types/node": "^26.6.5",
+    "@types/pg": "^8.23.1",
     "@types/react": "^19.3.0",
     "@types/react-dom": "^19.3.0",
     "fastify": "^5.12.7",
     "oxlint": "^1.89.0",
+    "pg": "^8.23.1",
     "react": "^19.3.1",
     "react-dom": "^19.3.1",
     "typescript": "^7.0.2",

release.mjs

@@ -10,8 +10,9 @@ const CHANGELOG = `${import.meta.dirname}/CHANGELOG.md`;
 
 const usage = `Usage: release.mjs [-h|--help] [-n|--dry-run] [--no-push] [-m|--message <message>]
 
-  -m, --message  commit message; default: the summary line of the newest CHANGELOG.md entry,
+  -m, --message  commit message; default: the summary of the newest CHANGELOG.md entry, the
-                 the line between blank lines right after its "## x.y.z" or "## x.y.z-n" heading
+                 paragraph between blank lines right after its "## x.y.z" or "## x.y.z-n"
+                 heading, its lines joined with single spaces
 
 The tag is the version of the heading: x.y.z for a release of the code, which must be the version
 of package.json and which the build workflow publishes, x.y.z-n, n from 2, for a later release
@@ -48,8 +49,8 @@ function git(...args) {
   if (status !== 0) process.exit(status ?? 1);
 }
 
-// The newest entry: its version from the first "## x.y.z" or "## x.y.z-n" heading, n from 2, and its summary line when
+// The newest entry: its version from the first "## x.y.z" or "## x.y.z-n" heading, n from 2, and its summary when the
-// the heading is followed by a blank line, one line that is not a "-" item, and another blank line.
+// heading is followed by a blank line and a paragraph that is not a "-" item; the paragraph's lines are joined with spaces.
 const lines = readFileSync(CHANGELOG, 'utf8').split('\n');
 const heading = lines.findIndex((line) => line.startsWith('## '));
 if (heading === -1) fail(`${CHANGELOG} has no "## x.y.z" entry`);
@@ -65,12 +66,16 @@ const packageVersion = JSON.parse(readFileSync(`${import.meta.dirname}/package.j
 if (revision === undefined && version !== packageVersion) {
   fail(`${CHANGELOG}: ${tag} is not the version of package.json, ${packageVersion}`);
 }
-const [above, line, below] = lines.slice(heading + 1, heading + 4);
+const end = lines.findIndex((line, index) => index > heading + 1 && line.trim() === '');
-const summary = above?.trim() === '' && below?.trim() === '' && line?.trim() && !line.startsWith('-') && !line.startsWith('#') ? line.trim() : undefined;
+const paragraph = end === -1 ? [] : lines.slice(heading + 2, end);
+const summary =
+  lines[heading + 1]?.trim() === '' && paragraph.length > 0 && !paragraph[0].startsWith('-') && !paragraph.some((line) => line.startsWith('#'))
+    ? paragraph.map((line) => line.trim()).join(' ')
+    : undefined;
 
 const message = values.message ?? summary;
 if (!message) {
-  fail(`no commit message: pass -m, or put a summary line between blank lines right after the newest heading of ${CHANGELOG}`);
+  fail(`no commit message: pass -m, or put a summary paragraph between blank lines right after the newest heading of ${CHANGELOG}`);
 }
 
 if (spawnSync('git', ['rev-parse', '-q', '--verify', `refs/tags/${tag}`], { cwd: import.meta.dirname }).status === 0) {

server/credentials.ts

@@ -8,7 +8,8 @@ import { decrypt, encrypt, encryptionKey } from './secrets.ts'
 
 /**
  * A credential store: the list under key of config.json at configPath, every entry of the kind the application gives,
- * with the names reserved for its own credentials. With missingAsEmpty a missing config.json reads as {}, and the
+ * with the names reserved for its own credentials. key is a key of config.json or a path of keys separated by dots,
+ * such as connections.pg, for a list in nested objects. With missingAsEmpty a missing config.json reads as {}, and the
  * first write creates it.
  */
 export type CredentialStore = {
@@ -114,9 +115,30 @@ export function credentialProblems(entries: unknown, store: Pick<CredentialStore
   return problems
 }
 
+const isObject = (value: unknown): value is Record<string, unknown> => value !== null && typeof value === 'object' && !Array.isArray(value)
+
+/** The value of data at key, a key or a path of keys separated by dots; undefined when it is not there. */
+function valueAt(data: Record<string, unknown>, key: string): unknown {
+  return key.split('.').reduce<unknown>((value, part) => (isObject(value) ? value[part] : undefined), data)
+}
+
+/**
+ * data with value at key, a key or a path of keys separated by dots, after the other keys of its object; the objects
+ * of the path that are missing, or are not objects, are created, and their other keys kept.
+ */
+function withValue(data: Record<string, unknown>, key: string, value: unknown): Record<string, unknown> {
+  const [first, ...rest] = key.split('.')
+  if (rest.length > 0) {
+    return { ...data, [first]: withValue(isObject(data[first]) ? data[first] : {}, rest.join('.'), value) }
+  }
+  const others = { ...data }
+  delete others[first]
+  return { ...others, [first]: value }
+}
+
 /** The entries of the store's key in config.json; a value that is not a list reads as none. */
 function entriesOf(data: Record<string, unknown>, store: CredentialStore): Record<string, unknown>[] {
-  const entries = data[store.key]
+  const entries = valueAt(data, store.key)
   return Array.isArray(entries) ? entries.filter((entry) => entry !== null && typeof entry === 'object') : []
 }
 
@@ -185,7 +207,7 @@ function toEntries(profiles: CredentialProfile[], data: Record<string, unknown>,
  */
 export function credentialValues(store: CredentialStore, name: string): CredentialValues {
   const { data } = read(store)
-  const [problem] = Object.entries(credentialProblems(data[store.key], store))
+  const [problem] = Object.entries(credentialProblems(valueAt(data, store.key), store))
   if (problem !== undefined) {
     throw new HttpError(500, `${problem[0]} in ${store.configPath} ${problem[1]}.`)
   }
@@ -234,8 +256,8 @@ export function registerCredentialRoutes(app: FastifyInstance, store: Credential
   function problemsOf(value: CredentialProfile[], data: Record<string, unknown>): Record<string, string> {
     const problems: Record<string, string> = {}
     for (const [path, message] of Object.entries(credentialProblems(toEntries(value, data, store, () => 'new'), store))) {
-      const [, index, field] = path.split('.')
+      const [index, field] = path.slice(store.key.length + 1).split('.')
-      problems[field === undefined ? index ?? store.key : `${index}.${field}`] = `${field ?? 'The credential'} ${message}.`
+      problems[field === undefined ? index || store.key : `${index}.${field}`] = `${field ?? 'The credential'} ${message}.`
     }
     if (key() === null) {
       value.forEach((profile, index) => {
@@ -279,11 +301,9 @@ export function registerCredentialRoutes(app: FastifyInstance, store: Credential
       throw new HttpError(422, 'The credentials are not valid.', problems)
     }
     const sealing = key()!
-    const others = { ...file.data }
-    delete others[store.key]
     const entries = toEntries(request.body.value, file.data, store, (secret) => encrypt(secret, sealing))
     try {
-      writeFileSync(store.configPath, `${JSON.stringify({ ...others, [store.key]: entries }, null, 2)}\n`)
+      writeFileSync(store.configPath, `${JSON.stringify(withValue(file.data, store.key, entries), null, 2)}\n`)
     } catch (error) {
       throw new HttpError(500, `${store.configPath} cannot be written: ${(error as Error).message}`)
     }

server/index.ts

@@ -4,3 +4,16 @@ export { HttpError, errorHandler, notFoundHandler, strict } from './http.ts'
 export { QUIET, createLog, fail, timestampsOn, type Log } from './log.ts'
 export { exitOnSignals, gitVersion, readJsonObject } from './process.ts'
 export { decrypt, encrypt, encryptionKey } from './secrets.ts'
+export type { TfInstance, TfModule, TfvarsFileStatus, TfvarsRevision } from '../shared/tfvars.ts'
+export { STATE_SCHEMA_PATTERN, TFVARS_FILE_PATTERN, TF_NAME_PATTERN } from '../shared/tfvars.ts'
+export {
+  createTfvarsStore,
+  tfvarsText,
+  versionOf,
+  type InstanceVariables,
+  type RevisionMeta,
+  type TfvarsDocument,
+  type TfvarsFile,
+  type TfvarsRevisionFiles,
+  type TfvarsStore,
+} from './tfvarsStore.ts'

server/sql/tfvars_store.sql

@@ -0,0 +1,173 @@
+-- The store of Terraform modules, their instances and the instances' variable files: the tables tf_modules,
+-- tf_instances, tf_variable_files and tf_variable_revisions, and the functions and procedures the store calls. The
+-- store applies the file on its first use in the schema its connection's search path names; every statement can run
+-- again.
+
+CREATE TABLE IF NOT EXISTS tf_modules (
+  name             text PRIMARY KEY CHECK (name ~ '^[a-z][a-z0-9-]*$'),
+  root             text NOT NULL CHECK (root <> ''),
+  description      text NOT NULL DEFAULT '',
+  configurator_url text
+);
+
+CREATE TABLE IF NOT EXISTS tf_instances (
+  module       text NOT NULL REFERENCES tf_modules (name),
+  name         text NOT NULL CHECK (name ~ '^[a-z][a-z0-9-]*$'),
+  state_schema text NOT NULL UNIQUE CHECK (state_schema ~ '^[a-z_][a-z0-9_]*$'),
+  created      timestamptz NOT NULL DEFAULT now(),
+  PRIMARY KEY (module, name)
+);
+
+CREATE TABLE IF NOT EXISTS tf_variable_files (
+  module   text NOT NULL,
+  instance text NOT NULL,
+  name     text NOT NULL CHECK (name ~ '^[A-Za-z0-9_.-]+\.tfvars\.json$'),
+  content  jsonb NOT NULL CHECK (jsonb_typeof(content) = 'object'),
+  previous jsonb CHECK (jsonb_typeof(previous) = 'object'),
+  updated  timestamptz NOT NULL DEFAULT now(),
+  PRIMARY KEY (module, instance, name),
+  FOREIGN KEY (module, instance) REFERENCES tf_instances (module, name) ON DELETE CASCADE
+);
+
+-- Every write of an instance's variable files: all its files after the write, by name, the schema version of their
+-- layout, null when not known, and the application that wrote them.
+CREATE TABLE IF NOT EXISTS tf_variable_revisions (
+  module   text NOT NULL,
+  instance text NOT NULL,
+  revision integer NOT NULL CHECK (revision > 0),
+  files    jsonb NOT NULL CHECK (jsonb_typeof(files) = 'object'),
+  schema   integer CHECK (schema > 0),
+  producer text NOT NULL CHECK (producer <> ''),
+  saved    timestamptz NOT NULL DEFAULT now(),
+  PRIMARY KEY (module, instance, revision),
+  FOREIGN KEY (module, instance) REFERENCES tf_instances (module, name) ON DELETE CASCADE
+);
+
+-- The files of an instance that has no revision are its revision 1, of an unknown schema and producer.
+INSERT INTO tf_variable_revisions (module, instance, revision, files, schema, producer, saved)
+SELECT f.module, f.instance, 1, jsonb_object_agg(f.name, f.content), NULL, 'unknown', max(f.updated)
+FROM tf_variable_files f
+WHERE NOT EXISTS (SELECT 1 FROM tf_variable_revisions r WHERE r.module = f.module AND r.instance = f.instance)
+GROUP BY f.module, f.instance
+ON CONFLICT DO NOTHING;
+
+-- The modules, by name.
+CREATE OR REPLACE FUNCTION tf_modules_list()
+RETURNS TABLE (name text, root text, description text, configurator_url text)
+LANGUAGE sql STABLE
+SET search_path FROM CURRENT
+AS $$
+  SELECT m.name, m.root, m.description, m.configurator_url FROM tf_modules m ORDER BY m.name
+$$;
+
+-- Creates a module, or changes the one of that name.
+CREATE OR REPLACE PROCEDURE tf_module_put(module_name text, module_root text, module_description text, module_configurator_url text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  INSERT INTO tf_modules (name, root, description, configurator_url)
+  VALUES (module_name, module_root, module_description, module_configurator_url)
+  ON CONFLICT (name) DO UPDATE SET root = excluded.root, description = excluded.description, configurator_url = excluded.configurator_url
+$$;
+
+-- Deletes a module; the foreign key of tf_instances refuses it while the module has instances.
+CREATE OR REPLACE PROCEDURE tf_module_delete(module_name text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  DELETE FROM tf_modules WHERE name = module_name
+$$;
+
+-- The instances of a module, by name.
+CREATE OR REPLACE FUNCTION tf_instances_list(module_name text)
+RETURNS TABLE (module text, name text, state_schema text, created timestamptz)
+LANGUAGE sql STABLE
+SET search_path FROM CURRENT
+AS $$
+  SELECT i.module, i.name, i.state_schema, i.created FROM tf_instances i WHERE i.module = module_name ORDER BY i.name
+$$;
+
+-- Creates an instance of a module with the schema of its state.
+CREATE OR REPLACE PROCEDURE tf_instance_create(module_name text, instance_name text, instance_state_schema text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  INSERT INTO tf_instances (module, name, state_schema) VALUES (module_name, instance_name, instance_state_schema)
+$$;
+
+-- Deletes an instance with its variable files.
+CREATE OR REPLACE PROCEDURE tf_instance_delete(module_name text, instance_name text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  DELETE FROM tf_instances WHERE module = module_name AND name = instance_name
+$$;
+
+-- The variable files of an instance, by name: content, whether the content it replaced is kept, and the time of the
+-- last write.
+CREATE OR REPLACE FUNCTION tf_variable_files_read(module_name text, instance_name text)
+RETURNS TABLE (name text, content jsonb, previous boolean, updated timestamptz)
+LANGUAGE sql STABLE
+SET search_path FROM CURRENT
+AS $$
+  SELECT f.name, f.content, f.previous IS NOT NULL, f.updated FROM tf_variable_files f
+  WHERE f.module = module_name AND f.instance = instance_name ORDER BY f.name
+$$;
+
+-- Keeps other writers out until the end of the transaction, from the comparison of the version to the commit.
+CREATE OR REPLACE PROCEDURE tf_variable_files_lock()
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  LOCK TABLE tf_variable_files IN EXCLUSIVE MODE
+$$;
+
+-- Writes a variable file of an instance, keeping the content it replaces as previous.
+CREATE OR REPLACE PROCEDURE tf_variable_file_put(module_name text, instance_name text, file_name text, file_content jsonb)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  INSERT INTO tf_variable_files (module, instance, name, content) VALUES (module_name, instance_name, file_name, file_content)
+  ON CONFLICT (module, instance, name) DO UPDATE SET previous = tf_variable_files.content, content = excluded.content, updated = now()
+$$;
+
+-- Deletes a variable file of an instance.
+CREATE OR REPLACE PROCEDURE tf_variable_file_delete(module_name text, instance_name text, file_name text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  DELETE FROM tf_variable_files WHERE module = module_name AND instance = instance_name AND name = file_name
+$$;
+
+-- Records the variable files of an instance as its next revision, with the schema of their layout and their producer;
+-- called with the lock of tf_variable_files_lock held.
+CREATE OR REPLACE PROCEDURE tf_variable_revision_add(module_name text, instance_name text, revision_schema integer, revision_producer text)
+LANGUAGE sql
+SET search_path FROM CURRENT
+AS $$
+  INSERT INTO tf_variable_revisions (module, instance, revision, files, schema, producer)
+  SELECT module_name, instance_name,
+    (SELECT coalesce(max(r.revision), 0) + 1 FROM tf_variable_revisions r WHERE r.module = module_name AND r.instance = instance_name),
+    (SELECT coalesce(jsonb_object_agg(f.name, f.content), '{}'::jsonb) FROM tf_variable_files f WHERE f.module = module_name AND f.instance = instance_name),
+    revision_schema, revision_producer
+$$;
+
+-- The revisions of an instance, newest first, with the names of their files.
+CREATE OR REPLACE FUNCTION tf_variable_revisions_list(module_name text, instance_name text)
+RETURNS TABLE (revision integer, schema integer, producer text, saved timestamptz, names text[])
+LANGUAGE sql STABLE
+SET search_path FROM CURRENT
+AS $$
+  SELECT r.revision, r.schema, r.producer, r.saved, ARRAY(SELECT jsonb_object_keys(r.files) ORDER BY 1)
+  FROM tf_variable_revisions r WHERE r.module = module_name AND r.instance = instance_name ORDER BY r.revision DESC
+$$;
+
+-- A revision of an instance with its files.
+CREATE OR REPLACE FUNCTION tf_variable_revision_get(module_name text, instance_name text, revision_number integer)
+RETURNS TABLE (revision integer, schema integer, producer text, saved timestamptz, files jsonb)
+LANGUAGE sql STABLE
+SET search_path FROM CURRENT
+AS $$
+  SELECT r.revision, r.schema, r.producer, r.saved, r.files
+  FROM tf_variable_revisions r WHERE r.module = module_name AND r.instance = instance_name AND r.revision = revision_number
+$$;

server/tfvarsStore.test.ts

@@ -0,0 +1,129 @@
+import assert from 'node:assert/strict'
+import { after, before, test } from 'node:test'
+import pg from 'pg'
+import { HttpError } from './http.ts'
+import { createTfvarsStore, tfvarsText, type TfvarsStore } from './tfvarsStore.ts'
+
+// The tests create a scratch database on the server the PG* variables name, connected to through the database
+// postgres, and drop it at the end.
+const database = `tfvars_store_test_${process.pid}`
+const admin = new pg.Client({ database: 'postgres' })
+let pool: pg.Pool
+let store: TfvarsStore
+
+before(async () => {
+  await admin.connect()
+  await admin.query(`CREATE DATABASE ${database}`)
+  pool = new pg.Pool({ database })
+  store = createTfvarsStore(pool)
+})
+
+after(async () => {
+  await pool?.end()
+  await admin.query(`DROP DATABASE IF EXISTS ${database}`)
+  await admin.end()
+})
+
+const status = async (promise: Promise<unknown>) => {
+  try {
+    await promise
+  } catch (error) {
+    assert.ok(error instanceof HttpError, String(error))
+    return error.statusCode
+  }
+  return 0
+}
+
+test('modules are created, changed, listed and deleted', async () => {
+  await store.modules.put({ name: 'router', root: 'router/terraform', description: 'VPN router', configuratorUrl: null })
+  await store.modules.put({ name: 'router', root: 'router/terraform', description: 'VPN router', configuratorUrl: 'http://localhost:7083/' })
+  await store.modules.put({ name: 'app', root: 'app', description: '', configuratorUrl: null })
+  assert.deepEqual(await store.modules.list(), [
+    { name: 'app', root: 'app', description: '', configuratorUrl: null },
+    { name: 'router', root: 'router/terraform', description: 'VPN router', configuratorUrl: 'http://localhost:7083/' },
+  ])
+  await store.modules.delete('app')
+  assert.deepEqual((await store.modules.list()).map((module) => module.name), ['router'])
+  assert.equal(await status(store.modules.put({ name: 'Bad', root: 'x', description: '', configuratorUrl: null })), 400)
+})
+
+test('instances are created and refused for a missing module or a name in use', async () => {
+  await store.instances.create('router', 'platform', 'terraform_remote_state')
+  await store.instances.create('router', 'test', 'tf_router_test')
+  assert.deepEqual((await store.instances.list('router')).map((instance) => [instance.name, instance.stateSchema]), [
+    ['platform', 'terraform_remote_state'],
+    ['test', 'tf_router_test'],
+  ])
+  assert.equal(await status(store.instances.create('missing', 'x', 'tf_missing_x')), 404)
+  assert.equal(await status(store.instances.create('router', 'test', 'tf_other')), 409)
+  assert.equal(await status(store.instances.create('router', 'other', 'tf_router_test')), 409)
+  assert.equal(await status(store.modules.delete('router')), 409)
+})
+
+const META = { schema: 1, producer: 'Test Configurator 1.0.0' }
+
+test('variable files are written with their version and refused against another version', async () => {
+  const variables = store.variables('router', 'test')
+  const empty = await variables.read()
+  assert.deepEqual(empty.files, [])
+  assert.equal(empty.version, '')
+  assert.equal(empty.revision, null)
+  assert.equal(await variables.write(empty.version, { 'platform.tfvars.json': tfvarsText({ a: 1 }), 'secrets.tfvars.json': tfvarsText({ s: 'x' }) }, META), true)
+  const written = await variables.read()
+  assert.deepEqual(written.files.map((file) => [file.name, file.content.toString('utf8')]), [
+    ['platform.tfvars.json', tfvarsText({ a: 1 })],
+    ['secrets.tfvars.json', tfvarsText({ s: 'x' })],
+  ])
+  assert.deepEqual(written.status.map((file) => file.previous), [false, false])
+  assert.equal(await variables.write(empty.version, { 'platform.tfvars.json': tfvarsText({ a: 2 }) }, META), false)
+  assert.equal(await variables.write(written.version, { 'platform.tfvars.json': tfvarsText({ a: 2 }) }, META), true)
+  const changed = await variables.read()
+  assert.deepEqual(changed.status.map((file) => file.previous), [true, false])
+  assert.notEqual(changed.version, written.version)
+  assert.equal(await variables.remove(written.version, 'secrets.tfvars.json', META), false)
+  assert.equal(await variables.remove(changed.version, 'secrets.tfvars.json', META), true)
+  assert.deepEqual((await variables.read()).files.map((file) => file.name), ['platform.tfvars.json'])
+  assert.deepEqual((await store.variables('router', 'platform').read()).files, [])
+  assert.equal(await status(variables.write((await variables.read()).version, { 'notes.json': tfvarsText({}) }, META)), 400)
+  assert.equal(await status(store.variables('router', 'missing').write('', { 'a.tfvars.json': tfvarsText({}) }, META)), 404)
+})
+
+test('every write is a revision with its files, schema and producer', async () => {
+  const variables = store.variables('router', 'test')
+  assert.deepEqual((await variables.revisions()).map((revision) => [revision.revision, revision.schema, revision.producer, revision.names]), [
+    [3, 1, META.producer, ['platform.tfvars.json']],
+    [2, 1, META.producer, ['platform.tfvars.json', 'secrets.tfvars.json']],
+    [1, 1, META.producer, ['platform.tfvars.json', 'secrets.tfvars.json']],
+  ])
+  const current = await variables.read()
+  assert.equal(await variables.write(current.version, {}, META), true)
+  assert.equal(await variables.write(current.version, { 'platform.tfvars.json': tfvarsText({ a: 3 }) }, { schema: null, producer: 'manage.mjs import' }), true)
+  const newest = (await variables.read()).revision
+  assert.deepEqual(newest && [newest.revision, newest.schema, newest.producer], [4, null, 'manage.mjs import'])
+  const first = await variables.revision(1)
+  assert.deepEqual(first?.files.map((file) => [file.name, file.content.toString('utf8')]), [
+    ['platform.tfvars.json', tfvarsText({ a: 1 })],
+    ['secrets.tfvars.json', tfvarsText({ s: 'x' })],
+  ])
+  assert.equal(await variables.revision(9), null)
+  assert.deepEqual(await store.variables('router', 'platform').revisions(), [])
+})
+
+test('the files of an instance without revisions become its revision 1 of an unknown producer', async () => {
+  await pool.query(`INSERT INTO tf_variable_files (module, instance, name, content) VALUES ('router', 'platform', 'a.tfvars.json', '{"b": 1}')`)
+  await pool.query('DELETE FROM tf_variable_revisions')
+  const again = createTfvarsStore(pool)
+  const revisions = await again.variables('router', 'platform').revisions()
+  assert.deepEqual(revisions.map((revision) => [revision.revision, revision.schema, revision.producer, revision.names]), [[1, null, 'unknown', ['a.tfvars.json']]])
+  assert.deepEqual((await again.variables('router', 'test').revisions()).map((revision) => revision.revision), [1])
+})
+
+test('an instance is deleted with its variable files, then its module', async () => {
+  await store.instances.delete('router', 'test')
+  await store.instances.delete('router', 'platform')
+  assert.deepEqual(await store.instances.list('router'), [])
+  assert.equal((await pool.query('SELECT count(*)::int AS n FROM tf_variable_files')).rows[0].n, 0)
+  assert.equal((await pool.query('SELECT count(*)::int AS n FROM tf_variable_revisions')).rows[0].n, 0)
+  await store.modules.delete('router')
+  assert.deepEqual(await store.modules.list(), [])
+})

server/tfvarsStore.ts

@@ -0,0 +1,222 @@
+import { createHash } from 'node:crypto'
+import { readFileSync } from 'node:fs'
+import type { Pool, PoolClient } from 'pg'
+import type { TfInstance, TfModule, TfvarsFileStatus, TfvarsRevision } from '../shared/tfvars.ts'
+import { HttpError } from './http.ts'
+
+/** A variable file of an instance: its name and its content, the object jsonb keeps written as JSON text. */
+export type TfvarsFile = { name: string; content: Buffer }
+
+/**
+ * The variable files of an instance, by name, with their version, versionOf the files, and their newest revision, null
+ * for an instance never written.
+ */
+export type TfvarsDocument = { files: TfvarsFile[]; status: TfvarsFileStatus[]; version: string; revision: TfvarsRevision | null }
+
+/** A revision with its files, by name. */
+export type TfvarsRevisionFiles = TfvarsRevision & { files: TfvarsFile[] }
+
+/** What a write records with the files: the schema version of their layout, null when not known, and the producer. */
+export type RevisionMeta = { schema: number | null; producer: string }
+
+/** The variable files of one instance. */
+export type InstanceVariables = {
+  read(): Promise<TfvarsDocument>
+  /**
+   * Writes the given files, name and JSON text of an object, when the files are still those of version, keeping each
+   * replaced content as its previous one, and records all files as the next revision with meta; answers false, writing
+   * nothing, when they changed since. A write of no file records no revision.
+   */
+  write(version: string, contents: Record<string, string>, meta: RevisionMeta): Promise<boolean>
+  /**
+   * Deletes the file name when the files are still those of version, and records the remaining files as the next
+   * revision with meta; answers false, deleting nothing, otherwise.
+   */
+  remove(version: string, name: string, meta: RevisionMeta): Promise<boolean>
+  /** The revisions, newest first. */
+  revisions(): Promise<TfvarsRevision[]>
+  /** The revision of the number with its files; null when there is none. */
+  revision(revision: number): Promise<TfvarsRevisionFiles | null>
+}
+
+/** The modules, the instances and their variable files in PostgreSQL. */
+export type TfvarsStore = {
+  modules: {
+    list(): Promise<TfModule[]>
+    /** Creates the module, or changes the one of its name. */
+    put(module: TfModule): Promise<void>
+    /** Deletes the module; HttpError 409 while it has instances. */
+    delete(name: string): Promise<void>
+  }
+  instances: {
+    list(module: string): Promise<TfInstance[]>
+    /** HttpError 409 for a name or a state schema in use, 404 for a module that does not exist. */
+    create(module: string, name: string, stateSchema: string): Promise<void>
+    /** Deletes the instance with its variable files. */
+    delete(module: string, name: string): Promise<void>
+  }
+  variables(module: string, instance: string): InstanceVariables
+}
+
+/** The text of a variable file as both stores write it: the object as JSON with two spaces, and a final newline. */
+export function tfvarsText(content: unknown): string {
+  return `${JSON.stringify(content, null, 2)}\n`
+}
+
+/** Identifies the variable files: the name and the SHA-256 of the content of each, in name order. */
+export function versionOf(files: TfvarsFile[]): string {
+  return [...files].sort((a, b) => a.name.localeCompare(b.name))
+    .map((file) => `${file.name}=${createHash('sha256').update(file.content).digest('hex')}`).join(':')
+}
+
+const SQL = new URL('./sql/tfvars_store.sql', import.meta.url)
+
+type FileRow = { name: string; content: object; previous: boolean; updated: Date }
+
+type RevisionRow = { revision: number; schema: number | null; producer: string; saved: Date; names: string[] }
+
+const revisionOf = (row: Omit<RevisionRow, 'names'>, names: string[]): TfvarsRevision =>
+  ({ revision: row.revision, schema: row.schema, producer: row.producer, saved: row.saved.toISOString(), names })
+
+/** The files of an object of revision files, by name, written as JSON text. */
+const filesOf = (files: Record<string, object>): TfvarsFile[] =>
+  Object.keys(files).sort().map((name) => ({ name, content: Buffer.from(tfvarsText(files[name]), 'utf8') }))
+
+/**
+ * The store of sql/tfvars_store.sql in the database of pool, applied at the first use in the schema of the
+ * connection's search path. A refused change is an HttpError: 409 for a name in use or a module that has instances,
+ * 404 for a module or an instance that does not exist, 400 for a value the tables do not accept.
+ */
+export function createTfvarsStore(pool: Pool): TfvarsStore {
+  let created: Promise<unknown> | null = null
+  const ready = () => (created ??= pool.query(readFileSync(SQL, 'utf8')))
+  const query = async <T extends object>(text: string, values: unknown[]): Promise<T[]> => {
+    await ready()
+    try {
+      return (await pool.query<T>(text, values)).rows
+    } catch (error) {
+      throw refused(error)
+    }
+  }
+  const document = (rows: FileRow[], newest: RevisionRow | undefined): TfvarsDocument => {
+    const files = rows.map((row) => ({ name: row.name, content: Buffer.from(tfvarsText(row.content), 'utf8') }))
+    return {
+      files,
+      status: rows.map((row, index) => ({ name: row.name, bytes: files[index].content.length, modified: row.updated.toISOString(), previous: row.previous })),
+      version: versionOf(files),
+      revision: newest === undefined ? null : revisionOf(newest, newest.names),
+    }
+  }
+  /** The files and the newest revision of an instance, read in one snapshot. */
+  const read = async (module: string, instance: string): Promise<TfvarsDocument> => {
+    await ready()
+    const client = await pool.connect()
+    try {
+      await client.query('BEGIN ISOLATION LEVEL REPEATABLE READ READ ONLY')
+      const files = await client.query<FileRow>('SELECT * FROM tf_variable_files_read($1, $2)', [module, instance])
+      const revisions = await client.query<RevisionRow>('SELECT * FROM tf_variable_revisions_list($1, $2) LIMIT 1', [module, instance])
+      await client.query('COMMIT')
+      return document(files.rows, revisions.rows[0])
+    } catch (error) {
+      await client.query('ROLLBACK')
+      throw refused(error)
+    } finally {
+      client.release()
+    }
+  }
+  /**
+   * Runs change in a transaction that holds the lock of the variable files, when they are still those of version, and
+   * records the files after it as the next revision with meta.
+   */
+  const locked = async (module: string, instance: string, version: string, meta: RevisionMeta, change: (client: PoolClient) => Promise<void>) => {
+    await ready()
+    const client = await pool.connect()
+    try {
+      await client.query('BEGIN')
+      await client.query('CALL tf_variable_files_lock()')
+      const { rows } = await client.query<FileRow>('SELECT * FROM tf_variable_files_read($1, $2)', [module, instance])
+      if (document(rows, undefined).version !== version) {
+        await client.query('ROLLBACK')
+        return false
+      }
+      await change(client)
+      await client.query('CALL tf_variable_revision_add($1, $2, $3, $4)', [module, instance, meta.schema, meta.producer])
+      await client.query('COMMIT')
+      return true
+    } catch (error) {
+      await client.query('ROLLBACK')
+      throw refused(error)
+    } finally {
+      client.release()
+    }
+  }
+  return {
+    modules: {
+      list: async () => (await query<{ name: string; root: string; description: string; configurator_url: string | null }>('SELECT * FROM tf_modules_list()', []))
+        .map((row) => ({ name: row.name, root: row.root, description: row.description, configuratorUrl: row.configurator_url })),
+      async put(module) {
+        await query('CALL tf_module_put($1, $2, $3, $4)', [module.name, module.root, module.description, module.configuratorUrl])
+      },
+      async delete(name) {
+        await query('CALL tf_module_delete($1)', [name])
+      },
+    },
+    instances: {
+      list: async (module) => (await query<{ module: string; name: string; state_schema: string; created: Date }>('SELECT * FROM tf_instances_list($1)', [module]))
+        .map((row) => ({ module: row.module, name: row.name, stateSchema: row.state_schema, created: row.created.toISOString() })),
+      async create(module, name, stateSchema) {
+        await query('CALL tf_instance_create($1, $2, $3)', [module, name, stateSchema])
+      },
+      async delete(module, name) {
+        await query('CALL tf_instance_delete($1, $2)', [module, name])
+      },
+    },
+    variables: (module, instance) => ({
+      read: () => read(module, instance),
+      write: async (version, contents, meta) => {
+        if (Object.keys(contents).length === 0) {
+          return (await read(module, instance)).version === version
+        }
+        return locked(module, instance, version, meta, async (client) => {
+          for (const [name, text] of Object.entries(contents)) {
+            await client.query('CALL tf_variable_file_put($1, $2, $3, $4::jsonb)', [module, instance, name, text])
+          }
+        })
+      },
+      remove: (version, name, meta) => locked(module, instance, version, meta, async (client) => {
+        await client.query('CALL tf_variable_file_delete($1, $2, $3)', [module, instance, name])
+      }),
+      revisions: async () => (await query<RevisionRow>('SELECT * FROM tf_variable_revisions_list($1, $2)', [module, instance]))
+        .map((row) => revisionOf(row, row.names)),
+      revision: async (revision) => {
+        const [row] = await query<Omit<RevisionRow, 'names'> & { files: Record<string, object> }>(
+          'SELECT * FROM tf_variable_revision_get($1, $2, $3)', [module, instance, revision])
+        if (row === undefined) {
+          return null
+        }
+        const files = filesOf(row.files)
+        return { ...revisionOf(row, files.map((file) => file.name)), files }
+      },
+    }),
+  }
+}
+
+/** The HttpError of an error of PostgreSQL that refuses a change, by its SQLSTATE; any other error as it is. */
+function refused(error: unknown): unknown {
+  const { code, constraint, detail } = error as { code?: string; constraint?: string; detail?: string }
+  const reason = detail ?? (error as Error).message
+  switch (code) {
+    case '23505':
+      return new HttpError(409, `The name is in use (${reason}).`)
+    case '23503':
+      if (reason.includes('is still referenced')) {
+        return new HttpError(409, `The module has instances; delete them first (${reason}).`)
+      }
+      return new HttpError(404, `The ${constraint === 'tf_instances_module_fkey' ? 'module' : 'instance'} does not exist (${reason}).`)
+    case '23514':
+    case '22P02':
+      return new HttpError(400, `The value is not allowed (${reason}).`)
+    default:
+      return error
+  }
+}

shared/index.ts

@@ -0,0 +1,3 @@
+export type { CredentialField, CredentialKind, CredentialProfile, CredentialsDocument } from './credentials.ts'
+export type { TfInstance, TfModule, TfvarsFileStatus, TfvarsRevision } from './tfvars.ts'
+export { STATE_SCHEMA_PATTERN, TFVARS_FILE_PATTERN, TF_NAME_PATTERN } from './tfvars.ts'

shared/tfvars.ts

@@ -0,0 +1,50 @@
+/** A registered Terraform module: a folder of Terraform code, relative to the modules folder of Cloud Platform. */
+export type TfModule = {
+  name: string
+  root: string
+  description: string
+  /** The address of the module's configurator, the application that edits the variables of its instances. */
+  configuratorUrl: string | null
+}
+
+/** A deployment of a module, whose state is kept in the schema stateSchema of the pg backend. */
+export type TfInstance = {
+  module: string
+  name: string
+  stateSchema: string
+  /** ISO 8601. */
+  created: string
+}
+
+/** A variable file of an instance, without its content. */
+export type TfvarsFileStatus = {
+  name: string
+  bytes: number
+  /** ISO 8601, the time of the last write. */
+  modified: string
+  /** Whether the content the last write replaced is kept. */
+  previous: boolean
+}
+
+/** A write of an instance's variable files, without their content. */
+export type TfvarsRevision = {
+  /** The number of the write, from 1 for each instance. */
+  revision: number
+  /** The schema version of the files' layout, as their producer gave it; null when not known. */
+  schema: number | null
+  /** The application that wrote the files, with its version. */
+  producer: string
+  /** ISO 8601. */
+  saved: string
+  /** The names of the files of the revision. */
+  names: string[]
+}
+
+/** The names of modules and instances: a lower-case letter, then lower-case letters, digits and hyphens. */
+export const TF_NAME_PATTERN = /^[a-z][a-z0-9-]*$/
+
+/** The names of variable files: letters, digits, '_', '.' and '-', ending in .tfvars.json. */
+export const TFVARS_FILE_PATTERN = /^[A-Za-z0-9_.-]+\.tfvars\.json$/
+
+/** The names of pg schemas of a state: a lower-case letter or '_', then lower-case letters, digits and '_'. */
+export const STATE_SCHEMA_PATTERN = /^[a-z_][a-z0-9_]*$/

tsconfig.build.json

@@ -6,5 +6,6 @@
     "outDir": "dist",
     "declaration": true,
     "rewriteRelativeImportExtensions": true
-  }
+  },
+  "exclude": ["dist", "**/*.test.ts"]
 }

web/RowDialog.tsx

@@ -6,12 +6,16 @@ import { useValidation } from './useValidation.ts'
 /**
  * A dialog that edits one row. The server validates the value as it changes (validatePath); onSave writes it and
  * the dialog closes when it succeeds. fields renders the inputs from the value, a setter and the problems by field;
- * below shows extra information from the validation, such as subnet placements.
+ * below shows extra information from the validation, such as subnet placements. body gives the value posted to
+ * validatePath, such as a whole document with the row put in, and select the problems by field and the message of
+ * the row taken from the answer; without them the row itself is posted and the answer is its validation.
  */
-export default function RowDialog<T, V extends Validation = Validation>(props: {
+export default function RowDialog<T, V = Validation>(props: {
   title: string
   initial: T
   validatePath: string
+  body?: (value: T) => unknown
+  select?: (result: V) => Validation
   saveLabel: string
   onSave: (value: T) => Promise<void>
   onCancel: () => void
@@ -21,9 +25,10 @@ export default function RowDialog<T, V extends Validation = Validation>(props: {
   const [value, setValue] = useState<T>(props.initial)
   const [saving, setSaving] = useState(false)
   const [error, setError] = useState<string | null>(null)
-  const validation = useValidation<V>(props.validatePath, value)
+  const validation = useValidation<V>(props.validatePath, props.body ? props.body(value) : value)
-  const problems = validation.result?.problems ?? {}
+  const selected = validation.result === null ? null : props.select ? props.select(validation.result) : validation.result as Validation
-  const message = validation.result?.message ?? ''
+  const problems = selected?.problems ?? {}
+  const message = selected?.message ?? ''
   const blocked = validation.pending || Object.keys(problems).length > 0 || message !== ''
 
   async function submit(event: FormEvent) {

web/index.ts

@@ -1,4 +1,6 @@
 export type { CredentialField, CredentialKind, CredentialProfile, CredentialsDocument } from '../shared/credentials.ts'
+export type { TfInstance, TfModule, TfvarsFileStatus } from '../shared/tfvars.ts'
+export { STATE_SCHEMA_PATTERN, TFVARS_FILE_PATTERN, TF_NAME_PATTERN } from '../shared/tfvars.ts'
 export { ApiError, request, type Validation } from './api.ts'
 export { createBrowserSettings } from './browserSettings.ts'
 export { default as Card } from './Card.tsx'

web/useValidation.ts

@@ -5,7 +5,7 @@ import { request, type Validation } from './api.ts'
  * Asks the server to validate value at path (a .../validate endpoint) 250 ms after it last
  * changed. pending is true until the answer for the current value arrives; until then the previous result stays.
  */
-export function useValidation<T extends Validation>(path: string | null, value: unknown): { result: T | null; error: string; pending: boolean } {
+export function useValidation<T = Validation>(path: string | null, value: unknown): { result: T | null; error: string; pending: boolean } {
   const key = path === null ? '' : `${path}\n${JSON.stringify(value)}`
   const [answer, setAnswer] = useState<{ key: string; result: T | null; error: string } | null>(null)