fix(aws-serverless): Take http_proxy into account when choosing

`useLayerExtension` default

The default setting for `useLayerExtension` now considers the `http_proxy` environment variable. When `http_proxy` is set, `useLayerExtension` will be off by default. If you use a `http_proxy` but would still like to make use of the Sentry Lambda extension, exempt `localhost` in a `no_proxy` environment variable.

Fixes: #17804

Author: andreiborza

CHANGELOG.md

@@ -4,6 +4,13 @@
 
 - "You miss 100 percent of the chances you don't take. — Wayne Gretzky" — Michael Scott
 
+### Important Changes
+
+- **fix(aws-serverless): Take `http_proxy` into account when choosing
+  `useLayerExtension` default ([#17817](https://github.com/getsentry/sentry-javascript/pull/17817))**
+
+The default setting for `useLayerExtension` now considers the `http_proxy` environment variable. When `http_proxy` is set, `useLayerExtension` will be off by default. If you use a `http_proxy` but would still like to make use of the Sentry Lambda extension, exempt `localhost` in a `no_proxy` environment variable.
+
 ## 10.16.0
 
 - feat(logs): Add internal `replay_is_buffering` flag ([#17752](https://github.com/getsentry/sentry-javascript/pull/17752))

packages/aws-serverless/src/init.ts

@@ -5,6 +5,44 @@ import { getDefaultIntegrationsWithoutPerformance, initWithoutDefaultIntegration
 import { DEBUG_BUILD } from './debug-build';
 import { awsIntegration } from './integration/aws';
 import { awsLambdaIntegration } from './integration/awslambda';
+
+/**
+ * Checks if proxy environment variables would interfere with the layer extension.
+ * The layer extension uses localhost:9000, so we need to check if proxy settings would prevent this.
+ */
+function shouldDisableLayerExtensionForProxy(): boolean {
+  const { http_proxy, no_proxy } = process.env;
+
+  // If no http proxy is configured, no interference (https_proxy doesn't affect HTTP requests)
+  if (!http_proxy) {
+    return false;
+  }
+
+  // Check if localhost is exempted by no_proxy
+  if (no_proxy) {
+    const exemptions = no_proxy.split(',').map(exemption => exemption.trim().toLowerCase());
+
+    // Handle common localhost exemption patterns explicitly
+    // If localhost is exempted, requests to the layer extension will not be proxied
+    const localhostExemptions = ['*', 'localhost', '127.0.0.1', '::1'];
+    if (exemptions.some(exemption => localhostExemptions.includes(exemption))) {
+      return false;
+    }
+  }
+
+  // If http_proxy is set and no localhost exemption, it would interfere
+  // The layer extension uses HTTP to localhost:9000, so only http_proxy matters
+  if (http_proxy) {
+    DEBUG_BUILD &&
+      debug.log(
+        'Disabling useLayerExtension due to http_proxy environment variable. Consider adding localhost to no_proxy to re-enable.',
+      );
+    return true;
+  }
+
+  return false;
+}
+
 /**
  * Get the default integrations for the AWSLambda SDK.
  */
@@ -28,9 +66,11 @@ export interface AwsServerlessOptions extends NodeOptions {
  */
 export function init(options: AwsServerlessOptions = {}): NodeClient | undefined {
   const sdkSource = getSDKSource();
+  const proxyWouldInterfere = shouldDisableLayerExtensionForProxy();
+
   const opts = {
     defaultIntegrations: getDefaultIntegrations(options),
-    useLayerExtension: sdkSource === 'aws-lambda-layer' && !options.tunnel,
+    useLayerExtension: sdkSource === 'aws-lambda-layer' && !options.tunnel && !proxyWouldInterfere,
     ...options,
   };
 
@@ -48,6 +88,11 @@ export function init(options: AwsServerlessOptions = {}): NodeClient | undefined
     } else {
       DEBUG_BUILD && debug.warn('The Sentry Lambda extension is only supported when using the AWS Lambda layer.');
     }
+  } else if (sdkSource === 'aws-lambda-layer' && proxyWouldInterfere) {
+    DEBUG_BUILD &&
+      debug.warn(
+        'Sentry Lambda extension disabled due to proxy environment variables (http_proxy/https_proxy). Consider adding localhost to no_proxy to re-enable.',
+      );
   }
 
   applySdkMetadata(opts, 'aws-serverless', ['aws-serverless'], sdkSource);

packages/aws-serverless/test/init.test.ts

@@ -1,6 +1,6 @@
 import { getSDKSource } from '@sentry/core';
 import { initWithoutDefaultIntegrations } from '@sentry/node';
-import { describe, expect, test, vi } from 'vitest';
+import { beforeEach, describe, expect, test, vi } from 'vitest';
 import type { AwsServerlessOptions } from '../src/init';
 import { init } from '../src/init';
 
@@ -18,6 +18,12 @@ const mockGetSDKSource = vi.mocked(getSDKSource);
 const mockInitWithoutDefaultIntegrations = vi.mocked(initWithoutDefaultIntegrations);
 
 describe('init', () => {
+  beforeEach(() => {
+    // Clean up environment variables between tests
+    delete process.env.http_proxy;
+    delete process.env.no_proxy;
+  });
+
   describe('Lambda extension setup', () => {
     test('should preserve user-provided tunnel option when Lambda extension is enabled', () => {
       mockGetSDKSource.mockReturnValue('aws-lambda-layer');
@@ -128,4 +134,256 @@ describe('init', () => {
       );
     });
   });
+
+  describe('proxy environment variables and layer extension', () => {
+    test('should enable useLayerExtension when no proxy env vars are set', () => {
+      mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+      const options: AwsServerlessOptions = {};
+
+      init(options);
+
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.objectContaining({
+          useLayerExtension: true,
+          tunnel: 'http://localhost:9000/envelope',
+        }),
+      );
+    });
+
+    test('should disable useLayerExtension when http_proxy is set', () => {
+      process.env.http_proxy = 'http://proxy.example.com:8080';
+      mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+      const options: AwsServerlessOptions = {};
+
+      init(options);
+
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.objectContaining({
+          useLayerExtension: false,
+        }),
+      );
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.not.objectContaining({
+          tunnel: expect.any(String),
+        }),
+      );
+    });
+
+    describe('no_proxy patterns', () => {
+      test('should enable useLayerExtension when no_proxy=* (wildcard)', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = '*';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should enable useLayerExtension when no_proxy contains localhost', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = 'localhost';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should enable useLayerExtension when no_proxy contains 127.0.0.1', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = '127.0.0.1';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should enable useLayerExtension when no_proxy contains ::1', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = '::1';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should enable useLayerExtension when no_proxy contains localhost in a comma-separated list', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = 'example.com,localhost,other.com';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should disable useLayerExtension when no_proxy does not contain localhost patterns', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = 'example.com,other.com';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: false,
+          }),
+        );
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.not.objectContaining({
+            tunnel: expect.any(String),
+          }),
+        );
+      });
+
+      test('should disable useLayerExtension when no_proxy contains host (no longer supported)', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = 'host';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: false,
+          }),
+        );
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.not.objectContaining({
+            tunnel: expect.any(String),
+          }),
+        );
+      });
+
+      test('should handle case-insensitive no_proxy values', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = 'LOCALHOST';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+
+      test('should handle whitespace in no_proxy values', () => {
+        process.env.http_proxy = 'http://proxy.example.com:8080';
+        process.env.no_proxy = ' localhost , example.com ';
+        mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+        const options: AwsServerlessOptions = {};
+
+        init(options);
+
+        expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+          expect.objectContaining({
+            useLayerExtension: true,
+            tunnel: 'http://localhost:9000/envelope',
+          }),
+        );
+      });
+    });
+
+    test('should respect explicit useLayerExtension=false even with no proxy interference', () => {
+      mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+      const options: AwsServerlessOptions = {
+        useLayerExtension: false,
+      };
+
+      init(options);
+
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.objectContaining({
+          useLayerExtension: false,
+        }),
+      );
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.not.objectContaining({
+          tunnel: expect.any(String),
+        }),
+      );
+    });
+
+    test('should respect explicit useLayerExtension=false even with proxy that would interfere', () => {
+      process.env.http_proxy = 'http://proxy.example.com:8080';
+      mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+      const options: AwsServerlessOptions = {
+        useLayerExtension: false,
+      };
+
+      init(options);
+
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.objectContaining({
+          useLayerExtension: false,
+        }),
+      );
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.not.objectContaining({
+          tunnel: expect.any(String),
+        }),
+      );
+    });
+
+    test('should respect explicit useLayerExtension=false even when no_proxy would enable it', () => {
+      process.env.http_proxy = 'http://proxy.example.com:8080';
+      process.env.no_proxy = 'localhost';
+      mockGetSDKSource.mockReturnValue('aws-lambda-layer');
+      const options: AwsServerlessOptions = {
+        useLayerExtension: false,
+      };
+
+      init(options);
+
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.objectContaining({
+          useLayerExtension: false,
+        }),
+      );
+      expect(mockInitWithoutDefaultIntegrations).toHaveBeenCalledWith(
+        expect.not.objectContaining({
+          tunnel: expect.any(String),
+        }),
+      );
+    });
+  });
 });