Placeholder for the database-related initialization + environment-based setup. (#9002)

Author: isoos

app/lib/database/database.dart

@@ -0,0 +1,57 @@
+// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:gcloud/service_scope.dart' as ss;
+import 'package:meta/meta.dart';
+import 'package:postgres/postgres.dart';
+import 'package:pub_dev/service/secret/backend.dart';
+import 'package:pub_dev/shared/env_config.dart';
+
+/// Sets the primary database service.
+void registerPrimaryDatabase(PrimaryDatabase database) =>
+    ss.register(#_primaryDatabase, database);
+
+/// The active primary database service.
+PrimaryDatabase? get primaryDatabase =>
+    ss.lookup(#_primaryDatabase) as PrimaryDatabase?;
+
+/// Access to the primary database connection and object mapping.
+class PrimaryDatabase {
+  final Pool _pg;
+
+  PrimaryDatabase._(this._pg);
+
+  /// Gets the connection string either from the environment variable or from
+  /// the secret backend, connects to it and registers the primary database
+  /// service in the current scope.
+  static Future<void> tryRegisterInScope() async {
+    final connectionString =
+        envConfig.pubPostgresUrl ??
+        (await secretBackend.lookup(SecretKey.postgresConnectionString));
+    if (connectionString == null) {
+      // ignore for now, must throw once we have the environment setup ready
+      return;
+    }
+    final database = await _fromConnectionString(connectionString);
+    registerPrimaryDatabase(database);
+    ss.registerScopeExitCallback(database.close);
+  }
+
+  static Future<PrimaryDatabase> _fromConnectionString(String value) async {
+    final pg = Pool.withUrl(value);
+    return PrimaryDatabase._(pg);
+  }
+
+  Future<void> close() async {
+    await _pg.close();
+  }
+
+  @visibleForTesting
+  Future<void> verifyConnection() async {
+    final rs = await _pg.execute('SELECT 1');
+    if (rs.length != 1) {
+      throw StateError('Connection is not returning expected rows.');
+    }
+  }
+}

app/lib/service/secret/models.dart

@@ -4,6 +4,10 @@
 
 /// Identifiers and secret keys.
 abstract class SecretKey {
+  /// Postgres connection string.
+  static const String postgresConnectionString = 'postgres-connection-string';
+
+  /// Redis connection string.
   static const String redisConnectionString = 'redis-connection-string';
 
   /// OAuth client secret.
@@ -27,6 +31,7 @@ abstract class SecretKey {
 
   /// List of all keys.
   static const values = [
+    postgresConnectionString,
     redisConnectionString,
     oauthClientSecret,
     announcement,

app/lib/service/services.dart

@@ -14,6 +14,7 @@ import 'package:gcloud/service_scope.dart';
 import 'package:gcloud/storage.dart';
 import 'package:googleapis_auth/auth_io.dart' as auth;
 import 'package:logging/logging.dart';
+import 'package:pub_dev/database/database.dart';
 import 'package:pub_dev/package/api_export/api_exporter.dart';
 import 'package:pub_dev/search/handlers.dart';
 import 'package:pub_dev/service/async_queue/async_queue.dart';
@@ -250,6 +251,7 @@ Future<R> _withPubServices<R>(FutureOr<R> Function() fn) async {
           await storageService.verifyBucketExistenceAndAccess(bucketName);
         }
 
+        await PrimaryDatabase.tryRegisterInScope();
         registerAccountBackend(AccountBackend(dbService));
         registerAdminBackend(AdminBackend(dbService));
         registerAnnouncementBackend(AnnouncementBackend());

app/test/shared/postgresql_ci_test.dart renamed to app/test/database/postgresql_ci_test.dart

@@ -4,9 +4,12 @@
 
 import 'package:clock/clock.dart';
 import 'package:postgres/postgres.dart';
+import 'package:pub_dev/database/database.dart';
 import 'package:pub_dev/shared/env_config.dart';
 import 'package:test/test.dart';
 
+import '../shared/test_services.dart';
+
 void main() {
   group('Postgresql connection on CI', () {
     test('connects to CI instance', () async {
@@ -32,5 +35,17 @@ void main() {
       await conn.execute('CREATE DATABASE $dbName');
       await conn.execute('DROP DATABASE $dbName');
     });
+
+    testWithProfile(
+      'registered database scope',
+      fn: () async {
+        final pubPostgresUrl = envConfig.pubPostgresUrl;
+        if (pubPostgresUrl == null) {
+          markTestSkipped('PUB_POSTGRES_URL was not specified.');
+          return;
+        }
+        await primaryDatabase!.verifyConnection();
+      },
+    );
   });
 }