Metrics refactor (#221)

Added the following:
* Basic metrics interfaces, a metrics factory and an implementation of those interfaces for Opentelemetry
* A MetricsEngine that handles creation and registration of metrics
* Creation and initialization helper methods for the existing replication, storage and API metrics
* MetricsEngine to the service context

Updates and fixes:
* Updated service runners to initialize the MetricsEngine and the existing metrics
* Updated replication modules to use the MetricsEngine instead of the old singleton metrics instance
* Moved metrics registration to service-core
* Removed unused dependencies in service package
* Bugfix: Only set up data replication metrics recorder for PostgresModule when it is started in a replication context.
* Moved the prometheus metrics port from an env variable to the collected powersync config

Author: Rentacookie

.changeset/beige-camels-reply.md

@@ -0,0 +1,12 @@
+---
+'@powersync/service-module-postgres-storage': minor
+'@powersync/service-module-mongodb-storage': minor
+'@powersync/service-core-tests': minor
+'@powersync/service-module-postgres': minor
+'@powersync/service-module-mongodb': minor
+'@powersync/service-core': minor
+'@powersync/service-module-mysql': minor
+'@powersync/service-types': minor
+---
+
+Refactored Metrics to use a MetricsEngine which is telemetry framework agnostic.

modules/module-mongodb-storage/test/src/setup.ts

@@ -1,13 +1,12 @@
 import { container } from '@powersync/lib-services-framework';
-import { test_utils } from '@powersync/service-core-tests';
 import { beforeAll, beforeEach } from 'vitest';
+import { METRICS_HELPER } from '@powersync/service-core-tests';
 
 beforeAll(async () => {
   // Executes for every test file
   container.registerDefaults();
-  await test_utils.initMetrics();
 });
 
 beforeEach(async () => {
-  await test_utils.resetMetrics();
+  METRICS_HELPER.resetMetrics();
 });

modules/module-mongodb/src/module/MongoModule.ts

@@ -37,11 +37,14 @@ export class MongoModule extends replication.ReplicationModule<types.MongoConnec
       id: this.getDefaultId(normalisedConfig.database ?? ''),
       syncRuleProvider: syncRuleProvider,
       storageEngine: context.storageEngine,
+      metricsEngine: context.metricsEngine,
       connectionFactory: connectionFactory,
       rateLimiter: new MongoErrorRateLimiter()
     });
   }
 
+  async onInitialized(context: system.ServiceContextContainer): Promise<void> {}
+
   /**
    * Combines base config with normalized connection settings
    */

modules/module-mongodb/src/replication/ChangeStream.ts

@@ -8,25 +8,20 @@ import {
   ReplicationAssertionError,
   ServiceError
 } from '@powersync/lib-services-framework';
-import {
-  BSON_DESERIALIZE_DATA_OPTIONS,
-  Metrics,
-  SaveOperationTag,
-  SourceEntityDescriptor,
-  SourceTable,
-  storage
-} from '@powersync/service-core';
+import { MetricsEngine, SaveOperationTag, SourceEntityDescriptor, SourceTable, storage } from '@powersync/service-core';
 import { DatabaseInputRow, SqliteRow, SqlSyncRules, TablePattern } from '@powersync/service-sync-rules';
 import { MongoLSN } from '../common/MongoLSN.js';
 import { PostImagesOption } from '../types/types.js';
 import { escapeRegExp } from '../utils.js';
 import { MongoManager } from './MongoManager.js';
 import { constructAfterRecord, createCheckpoint, getCacheIdentifier, getMongoRelation } from './MongoRelation.js';
 import { CHECKPOINTS_COLLECTION } from './replication-utils.js';
+import { ReplicationMetric } from '@powersync/service-types';
 
 export interface ChangeStreamOptions {
   connections: MongoManager;
   storage: storage.SyncRulesBucketStorage;
+  metrics: MetricsEngine;
   abort_signal: AbortSignal;
 }
 
@@ -59,13 +54,15 @@ export class ChangeStream {
   private connections: MongoManager;
   private readonly client: mongo.MongoClient;
   private readonly defaultDb: mongo.Db;
+  private readonly metrics: MetricsEngine;
 
   private abort_signal: AbortSignal;
 
   private relation_cache = new Map<string | number, storage.SourceTable>();
 
   constructor(options: ChangeStreamOptions) {
     this.storage = options.storage;
+    this.metrics = options.metrics;
     this.group_id = options.storage.group_id;
     this.connections = options.connections;
     this.client = this.connections.client;
@@ -318,7 +315,7 @@ export class ChangeStream {
       }
 
       at += docBatch.length;
-      Metrics.getInstance().rows_replicated_total.add(docBatch.length);
+      this.metrics.getCounter(ReplicationMetric.ROWS_REPLICATED).add(docBatch.length);
       const duration = performance.now() - lastBatch;
       lastBatch = performance.now();
       logger.info(
@@ -446,7 +443,7 @@ export class ChangeStream {
       return null;
     }
 
-    Metrics.getInstance().rows_replicated_total.add(1);
+    this.metrics.getCounter(ReplicationMetric.ROWS_REPLICATED).add(1);
     if (change.operationType == 'insert') {
       const baseRecord = constructAfterRecord(change.fullDocument);
       return await batch.save({

modules/module-mongodb/src/replication/ChangeStreamReplicationJob.ts

@@ -71,6 +71,7 @@ export class ChangeStreamReplicationJob extends replication.AbstractReplicationJ
       const stream = new ChangeStream({
         abort_signal: this.abortController.signal,
         storage: this.options.storage,
+        metrics: this.options.metrics,
         connections: connectionManager
       });
       await stream.replicate();

modules/module-mongodb/src/replication/ChangeStreamReplicator.ts

@@ -20,6 +20,7 @@ export class ChangeStreamReplicator extends replication.AbstractReplicator<Chang
     return new ChangeStreamReplicationJob({
       id: this.createJobId(options.storage.group_id),
       storage: options.storage,
+      metrics: this.metrics,
       connectionFactory: this.connectionFactory,
       lock: options.lock,
       rateLimiter: new MongoErrorRateLimiter()

modules/module-mongodb/test/src/change_stream_utils.ts

@@ -1,12 +1,14 @@
 import { mongo } from '@powersync/lib-service-mongodb';
 import {
   BucketStorageFactory,
+  createCoreReplicationMetrics,
+  initializeCoreReplicationMetrics,
   InternalOpId,
   ProtocolOpId,
   ReplicationCheckpoint,
   SyncRulesBucketStorage
 } from '@powersync/service-core';
-import { test_utils } from '@powersync/service-core-tests';
+import { METRICS_HELPER, test_utils } from '@powersync/service-core-tests';
 
 import { ChangeStream, ChangeStreamOptions } from '@module/replication/ChangeStream.js';
 import { MongoManager } from '@module/replication/MongoManager.js';
@@ -38,7 +40,10 @@ export class ChangeStreamTestContext {
   constructor(
     public factory: BucketStorageFactory,
     public connectionManager: MongoManager
-  ) {}
+  ) {
+    createCoreReplicationMetrics(METRICS_HELPER.metricsEngine);
+    initializeCoreReplicationMetrics(METRICS_HELPER.metricsEngine);
+  }
 
   async dispose() {
     this.abortController.abort();
@@ -78,6 +83,7 @@ export class ChangeStreamTestContext {
     }
     const options: ChangeStreamOptions = {
       storage: this.storage,
+      metrics: METRICS_HELPER.metricsEngine,
       connections: this.connectionManager,
       abort_signal: this.abortController.signal
     };

modules/module-mongodb/test/src/setup.ts

@@ -1,15 +1,13 @@
 import { container } from '@powersync/lib-services-framework';
-import { test_utils } from '@powersync/service-core-tests';
+import { METRICS_HELPER } from '@powersync/service-core-tests';
 import { beforeEach } from 'node:test';
 import { beforeAll } from 'vitest';
 
 beforeAll(async () => {
   // Executes for every test file
   container.registerDefaults();
-
-  await test_utils.initMetrics();
 });
 
 beforeEach(async () => {
-  await test_utils.resetMetrics();
+  METRICS_HELPER.resetMetrics();
 });

modules/module-mysql/src/module/MySQLModule.ts

@@ -25,9 +25,7 @@ export class MySQLModule extends replication.ReplicationModule<types.MySQLConnec
     });
   }
 
-  async initialize(context: system.ServiceContextContainer): Promise<void> {
-    await super.initialize(context);
-  }
+  async onInitialized(context: system.ServiceContextContainer): Promise<void> {}
 
   protected createRouteAPIAdapter(): api.RouteAPI {
     return new MySQLRouteAPIAdapter(this.resolveConfig(this.decodedConfig!));
@@ -42,6 +40,7 @@ export class MySQLModule extends replication.ReplicationModule<types.MySQLConnec
       id: this.getDefaultId(normalisedConfig.database),
       syncRuleProvider: syncRuleProvider,
       storageEngine: context.storageEngine,
+      metricsEngine: context.metricsEngine,
       connectionFactory: connectionFactory,
       rateLimiter: new MySQLErrorRateLimiter()
     });

modules/module-mysql/src/replication/BinLogReplicationJob.ts

@@ -63,6 +63,7 @@ export class BinLogReplicationJob extends replication.AbstractReplicationJob {
       const stream = new BinLogStream({
         abortSignal: this.abortController.signal,
         storage: this.options.storage,
+        metrics: this.options.metrics,
         connections: connectionManager
       });
       await stream.replicate();