Migration service (#47)

Author: adam-fowler

Sources/PostgresMigrations/MigrationService.swift

@@ -0,0 +1,52 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Hummingbird server framework project
+//
+// Copyright (c) 2025 the Hummingbird authors
+// Licensed under Apache License v2.0
+//
+// See LICENSE.txt for license information
+// See hummingbird/CONTRIBUTORS.txt for the list of Hummingbird authors
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+//===----------------------------------------------------------------------===//
+
+import Logging
+import PostgresNIO
+import ServiceLifecycle
+
+/// Service that runs a database migration
+public struct DatabaseMigrationService: Service {
+    let client: PostgresClient
+    let groups: [DatabaseMigrationGroup]
+    let migrations: DatabaseMigrations
+    let logger: Logger
+    let dryRun: Bool
+
+    ///  Initialize DatabaseMigrationService
+    /// - Parameters:
+    ///   - client: Postgres client
+    ///   - migrations: Migrations to apply
+    ///   - groups: Migration groups to apply
+    ///   - logger: logger
+    ///   - dryRun: Is this a dry run
+    public init(
+        client: PostgresClient,
+        migrations: DatabaseMigrations,
+        groups: [DatabaseMigrationGroup] = [],
+        logger: Logger,
+        dryRun: Bool
+    ) {
+        self.client = client
+        self.groups = groups
+        self.migrations = migrations
+        self.logger = logger
+        self.dryRun = dryRun
+    }
+
+    public func run() async throws {
+        try await self.migrations.apply(client: self.client, groups: self.groups, logger: self.logger, dryRun: self.dryRun)
+        try? await gracefulShutdown()
+    }
+}

Tests/PostgresMigrationsTests/MigrationTests.swift

@@ -2,6 +2,7 @@ import Atomics
 import Foundation
 import Logging
 import PostgresNIO
+import ServiceLifecycle
 import XCTest
 
 @testable import PostgresMigrations
@@ -423,6 +424,51 @@ final class MigrationTests: XCTestCase {
             try await migrations.apply(client: client, groups: [.default, .test], logger: Self.logger, dryRun: false)
         }
     }
+
+    func testMigrationService() async throws {
+        struct WaitRevertMigrationService: Service {
+            let client: PostgresClient
+            let migrations: DatabaseMigrations
+            let logger: Logger
+            func run() async throws {
+                try await migrations.waitUntilCompleted()
+                try await migrations.revert(client: client, groups: [.test], logger: logger, dryRun: false)
+            }
+        }
+        let logger = {
+            var logger = Logger(label: "MigrationTests")
+            logger.logLevel = .debug
+            return logger
+        }()
+        let client = try await PostgresClient(
+            configuration: getPostgresConfiguration(),
+            backgroundLogger: logger
+        )
+        let migrations = DatabaseMigrations()
+        await migrations.add(TestMigration(name: "testMigrationService", group: .test))
+        let serviceGroup = ServiceGroup(
+            configuration: .init(
+                services: [
+                    client,
+                    DatabaseMigrationService(
+                        client: client,
+                        migrations: migrations,
+                        groups: [.test],
+                        logger: logger,
+                        dryRun: false
+                    ),
+                    WaitRevertMigrationService(client: client, migrations: migrations, logger: logger),
+                ],
+                gracefulShutdownSignals: [.sigterm, .sigint],
+                logger: logger
+            )
+        )
+        do {
+            try await serviceGroup.run()
+        } catch let error as ServiceGroupError where error == .serviceFinishedUnexpectedly() {
+            // ... we're good
+        }
+    }
 }
 
 extension DatabaseMigrationGroup {