fix: the web service waits for the PostgreSQL driver instead of failing at start.

debian-package/src/usr/lib/vpn-router/web

@@ -30,7 +30,9 @@ default the address the service listens on, is the last entry of its X-Forwarded
 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.
 
-The service first initializes, without listening: it makes the signing key and the refresh
+The service first initializes, without listening: it loads the PostgreSQL driver
+(vpnrouter_auth.driver; psycopg finds libpq through the linker cache, which the package manager
+refreshes only at the end of an installation), then it makes the signing key and the refresh
 tokens' database (vpnrouter_auth), retrying every INIT_RETRY_SECONDS until both are ready and
 logging each failure. Then it listens.
 
@@ -58,7 +60,6 @@ from http.server import BaseHTTPRequestHandler
 sys.path.insert(0, os.path.dirname(os.path.realpath(__file__)))
 
 import ldap
-import psycopg
 
 import vpnrouter
 import vpnrouter_auth
@@ -440,8 +441,8 @@ def users(state, method, path, body):
         return USER_STATUS.get(failure.status, 500), {'error': str(failure)}
     except (ldap.LDAPError, OSError) as exc:
         return 500, {'error': f'the user directory failed: {exc}'}
-    except psycopg.Error as exc:
-        return 500, {'error': f'the token database failed: {exc}'}
+    except vpnrouter_auth.DatabaseError as exc:
+        return 500, {'error': str(exc)}
     except SystemExit as exc:
         # vpnrouter ends with SystemExit, carrying the reason, on a configuration it cannot read.
         return 500, {'error': str(exc.code)}
@@ -544,8 +545,8 @@ def auth(path, body):
         return (401 if failure.status == 3 else USER_STATUS.get(failure.status, 500)), {'error': str(failure)}
     except (ldap.LDAPError, OSError) as exc:
         return 500, {'error': f'the user directory failed: {exc}'}
-    except psycopg.Error as exc:
-        return 500, {'error': f'the token database failed: {exc}'}
+    except vpnrouter_auth.DatabaseError as exc:
+        return 500, {'error': str(exc)}
     except SystemExit as exc:
         return 500, {'error': str(exc.code)}
 
@@ -696,19 +697,22 @@ def log(message):
 
 
 def initialize():
-    """Make the signing key and the refresh tokens' database, retrying every INIT_RETRY_SECONDS until both are ready."""
+    """Load the PostgreSQL driver, make the signing key and the refresh tokens' database, retrying every INIT_RETRY_SECONDS until all are ready."""
     reported = None
     while True:
-        phase = 'reading the configuration'
+        phase = 'loading the PostgreSQL driver'
         try:
+            vpnrouter_auth.driver()
+            phase = 'reading the configuration'
             cfg = vpnrouter.load_config()
             phase = 'making the signing key'
             vpnrouter_auth.ensure_key()
             phase = 'creating the token database'
             vpnrouter_auth.provision(cfg)
             phase = 'connecting to the token database'
-            vpnrouter_auth.connect(cfg).close()
-        except (OSError, psycopg.Error, SystemExit) as exc:
+            with vpnrouter_auth.database(cfg):
+                pass
+        except (OSError, SystemExit, vpnrouter_auth.DatabaseError) as exc:
             error = f'{phase} failed: {exc.code if isinstance(exc, SystemExit) else exc}'
             if error != reported:
                 log(f'{error}; retrying every {INIT_RETRY_SECONDS} seconds')