fix(node): Flush buffered metrics on process exit

packages/node/src/sdk/client.ts

@@ -5,6 +5,7 @@ import type { ServerRuntimeClientOptions } from '@sentry/core/server';
 import {
   _INTERNAL_clearAiProviderSkips,
   _INTERNAL_flushLogsBuffer,
+  _INTERNAL_flushMetricsBuffer,
   _INTERNAL_setDeferSegmentSpanCapture,
   applySdkMetadata,
   debug,
@@ -38,6 +39,7 @@ export class NodeClient extends ServerRuntimeClient<NodeClientOptions> {
   private _clientReportInterval: NodeJS.Timeout | undefined;
   private _clientReportOnExitFlushListener: (() => void) | undefined;
   private _logOnExitFlushListener: (() => void) | undefined;
+  private _metricsOnExitFlushListener: (() => void) | undefined;
 
   public constructor(options: NodeClientOptions) {
     const serverName =
@@ -63,6 +65,10 @@ export class NodeClient extends ServerRuntimeClient<NodeClientOptions> {
       _INTERNAL_flushLogsBuffer(this);
     };
 
+    this._metricsOnExitFlushListener = () => {
+      _INTERNAL_flushMetricsBuffer(this);
+    };
+
     if (serverName) {
       this.on('beforeCaptureLog', log => {
         log.attributes = {
@@ -73,6 +79,7 @@ export class NodeClient extends ServerRuntimeClient<NodeClientOptions> {
     }
 
     process.on('beforeExit', this._logOnExitFlushListener);
+    process.on('beforeExit', this._metricsOnExitFlushListener);
 
     // Enable deferred segment-span transaction capture here, in the constructor, rather than in
     // `initOtel`. Every client runs its constructor exactly once, whereas `initOtel` only runs on
@@ -158,6 +165,10 @@ export class NodeClient extends ServerRuntimeClient<NodeClientOptions> {
       process.off('beforeExit', this._logOnExitFlushListener);
     }
 
+    if (this._metricsOnExitFlushListener) {
+      process.off('beforeExit', this._metricsOnExitFlushListener);
+    }
+
     const allEventsSent = await super.close(timeout);
     if (this.traceProvider) {
       await this.traceProvider.shutdown();

packages/node/test/sdk/client.test.ts

@@ -397,35 +397,39 @@ describe('NodeClient', () => {
       expect(forceFlushSpy).toHaveBeenCalledTimes(1);
     });
 
-    it('stops client report tracking if it was started', async () => {
-      const processOffSpy = vi.spyOn(process, 'off');
-      const clearIntervalSpy = vi.spyOn(globalThis, 'clearInterval');
-
+    it('stops client report tracking when closed', async () => {
+      const originalListeners = process.listeners('beforeExit');
       const client = new NodeClient(getDefaultNodeClientOptions({ sendClientReports: true }));
+      const listenersBeforeTracking = process.listeners('beforeExit');
+      const setIntervalSpy = vi.spyOn(globalThis, 'setInterval');
+      const clearIntervalSpy = vi.spyOn(globalThis, 'clearInterval');
 
       client.startClientReportTracking();
 
-      const result = await client.close();
+      const addedListeners = process
+        .listeners('beforeExit')
+        .filter(listener => !listenersBeforeTracking.includes(listener));
+      const [intervalResult] = setIntervalSpy.mock.results;
 
-      expect(result).toBe(true);
+      await client.close();
 
+      expect(addedListeners).toHaveLength(1);
+      expect(process.listeners('beforeExit')).toEqual(originalListeners);
+      expect(setIntervalSpy).toHaveBeenCalledTimes(1);
       expect(clearIntervalSpy).toHaveBeenCalledTimes(1);
-
-      // removes `_clientReportOnExitFlushListener`
-      expect(processOffSpy).toHaveBeenNthCalledWith(1, 'beforeExit', expect.any(Function));
+      expect(clearIntervalSpy).toHaveBeenCalledWith(intervalResult?.value);
     });
 
-    it('stops log capture if it was started', async () => {
-      const processOffSpy = vi.spyOn(process, 'off');
+    it('removes log and metric exit listeners when closed', async () => {
+      const originalListeners = process.listeners('beforeExit');
+      const client = new NodeClient(getDefaultNodeClientOptions({ sendClientReports: false }));
 
-      const client = new NodeClient(getDefaultNodeClientOptions());
+      const addedListeners = process.listeners('beforeExit').filter(listener => !originalListeners.includes(listener));
 
-      const result = await client.close();
-
-      expect(result).toBe(true);
+      await client.close();
 
-      // removes `_logOnExitFlushListener`
-      expect(processOffSpy).toHaveBeenNthCalledWith(1, 'beforeExit', expect.any(Function));
+      expect(addedListeners).toHaveLength(2);
+      expect(process.listeners('beforeExit')).toEqual(originalListeners);
     });
   });