style(tracer): apply stricter linting (#4570)

Author: dreamorosi

packages/tracer/src/Tracer.ts

@@ -41,29 +41,24 @@ import type {
 const { Subsegment: XraySubsegment } = xraySdk;
 
 /**
- * ## Intro
  * Tracer is an opinionated thin wrapper for [AWS X-Ray SDK for Node.js](https://github.com/aws/aws-xray-sdk-node).
  *
  * Tracing data can be visualized through AWS X-Ray Console.
  *
- * ## Key features
- *   * Auto capture cold start as annotation, and responses or full exceptions as metadata
- *   * Auto-disable when not running in AWS Lambda environment
- *   * Automatically trace HTTP(s) clients and generate segments for each request
- *   * Support tracing functions via decorators, middleware, and manual instrumentation
- *   * Support tracing AWS SDK v2 and v3 via AWS X-Ray SDK for Node.js
+ * **Key features**
+ * - Auto capture cold start as annotation, and responses or full exceptions as metadata
+ * - Auto-disable when not running in AWS Lambda environment
+ * - Automatically trace HTTP(s) clients and generate segments for each request
+ * - Support tracing functions via decorators, middleware, and manual instrumentation
+ * - Support tracing AWS SDK v2 and v3 via AWS X-Ray SDK for Node.js
  *
- * ## Usage
- *
- * For more usage examples, see [our documentation](https://docs.powertools.aws.dev/lambda/typescript/latest/core/tracer/).
- *
- * ### Functions usage with middleware
+ * **Functions usage with middleware**
  *
  * If you use function-based Lambda handlers you can use the {@link Tracer.captureLambdaHandler} middy middleware to automatically:
- * * handle the subsegment lifecycle
- * * add the `ServiceName` and `ColdStart` annotations
- * * add the function response as metadata
- * * add the function error as metadata (if any)
+ * - handle the subsegment lifecycle
+ * - add the `ServiceName` and `ColdStart` annotations
+ * - add the function response as metadata
+ * - add the function error as metadata (if any)
  *
  * @example
  * ```typescript
@@ -80,13 +75,13 @@ const { Subsegment: XraySubsegment } = xraySdk;
  * export const handler = middy(lambdaHandler).use(captureLambdaHandler(tracer));
  * ```
  *
- * ### Object oriented usage with decorators
+ * **Object oriented usage with decorators**
  *
  * If instead you use TypeScript Classes to wrap your Lambda handler you can use the {@link Tracer.captureLambdaHandler} decorator to automatically:
- * * handle the subsegment lifecycle
- * * add the `ServiceName` and `ColdStart` annotations
- * * add the function response as metadata
- * * add the function error as metadata (if any)
+ * - handle the subsegment lifecycle
+ * - add the `ServiceName` and `ColdStart` annotations
+ * - add the function response as metadata
+ * - add the function error as metadata (if any)
  *
  * @example
  * ```typescript
@@ -106,7 +101,7 @@ const { Subsegment: XraySubsegment } = xraySdk;
  * export const handler = handlerClass.handler.bind(handlerClass);
  * ```
  *
- * ### Functions usage with manual instrumentation
+ * **Functions usage with manual instrumentation**
  *
  * If you prefer to manually instrument your Lambda handler you can use the methods in the tracer class directly.
  *
@@ -391,10 +386,10 @@ class Tracer extends Utility implements TracerInterface {
    * A decorator automating capture of metadata and annotations on segments or subsegments for a Lambda Handler.
    *
    * Using this decorator on your handler function will automatically:
-   * * handle the subsegment lifecycle
-   * * add the `ColdStart` annotation
-   * * add the function response as metadata
-   * * add the function error as metadata (if any)
+   * - handle the subsegment lifecycle
+   * - add the `ColdStart` annotation
+   * - add the function response as metadata
+   * - add the function error as metadata (if any)
    *
    * Note: Currently TypeScript only supports decorators on classes and methods. If you are using the
    * function syntax, you should use the middleware instead.
@@ -475,9 +470,9 @@ class Tracer extends Utility implements TracerInterface {
    * A decorator automating capture of metadata and annotations on segments or subsegments for an arbitrary function.
    *
    * Using this decorator on your function will automatically:
-   * * handle the subsegment lifecycle
-   * * add the function response as metadata
-   * * add the function error as metadata (if any)
+   * - handle the subsegment lifecycle
+   * - add the function response as metadata
+   * - add the function error as metadata (if any)
    *
    * Note: Currently TypeScript only supports decorators on classes and methods. If you are using the
    * function syntax, you should use the middleware instead.

packages/tracer/src/middleware/middy.ts

@@ -11,10 +11,10 @@ import type { CaptureLambdaHandlerOptions } from '../types/Tracer.js';
  * A middy middleware automating capture of metadata and annotations on segments or subsegments for a Lambda Handler.
  *
  * Using this middleware on your handler function will automatically:
- * * handle the subsegment lifecycle
- * * add the `ColdStart` annotation
- * * add the function response as metadata
- * * add the function error as metadata (if any)
+ * - handle the subsegment lifecycle
+ * - add the `ColdStart` annotation
+ * - add the function response as metadata
+ * - add the function error as metadata (if any)
  *
  * @example
  * ```typescript
@@ -33,7 +33,6 @@ import type { CaptureLambdaHandlerOptions } from '../types/Tracer.js';
  *
  * @param target - The Tracer instance to use for tracing
  * @param options - (_optional_) Options for the middleware
- * @returns middleware - The middy middleware object
  */
 const captureLambdaHandler = (
   target: Tracer,
@@ -83,9 +82,7 @@ const captureLambdaHandler = (
     target.setSegment(lambdaSegment);
   };
 
-  const captureLambdaHandlerBefore = async (
-    request: MiddyLikeRequest
-  ): Promise<void> => {
+  const before = (request: MiddyLikeRequest) => {
     if (target.isTracingEnabled()) {
       open();
       setCleanupFunction(request);
@@ -94,9 +91,7 @@ const captureLambdaHandler = (
     }
   };
 
-  const captureLambdaHandlerAfter = async (
-    request: MiddyLikeRequest
-  ): Promise<void> => {
+  const after = (request: MiddyLikeRequest) => {
     if (target.isTracingEnabled()) {
       if (options?.captureResponse ?? true) {
         target.addResponseAsMetadata(request.response, process.env._HANDLER);
@@ -105,19 +100,17 @@ const captureLambdaHandler = (
     }
   };
 
-  const captureLambdaHandlerError = async (
-    request: MiddyLikeRequest
-  ): Promise<void> => {
+  const onError = (request: MiddyLikeRequest) => {
     if (target.isTracingEnabled()) {
       target.addErrorAsMetadata(request.error as Error);
       close();
     }
   };
 
   return {
-    before: captureLambdaHandlerBefore,
-    after: captureLambdaHandlerAfter,
-    onError: captureLambdaHandlerError,
+    before,
+    after,
+    onError,
   };
 };
 

packages/tracer/src/provider/ProviderService.ts

@@ -27,8 +27,8 @@ import { subscribe } from 'node:diagnostics_channel';
 import http from 'node:http';
 import https from 'node:https';
 import { addUserAgentMiddleware } from '@aws-lambda-powertools/commons';
-import type { DiagnosticsChannel } from 'undici-types';
 import { getXRayTraceIdFromEnv } from '@aws-lambda-powertools/commons/utils/env';
+import type { DiagnosticsChannel } from 'undici-types';
 import {
   findHeaderAndDecode,
   getRequestURL,
@@ -172,7 +172,7 @@ class ProviderService implements ProviderServiceInterface {
           response: {
             status,
             ...(contentLenght && {
-              content_length: Number.parseInt(contentLenght),
+              content_length: Number.parseInt(contentLenght, 10),
             }),
           },
         };

packages/tracer/src/types/Tracer.ts

@@ -32,10 +32,8 @@ type TracerOptions = {
 /**
  * Options for handler decorators and middleware.
  *
- * Options supported:
- * * `captureResponse` - (_optional_) - Disable response serialization as subsegment metadata
+ * **Middleware usage**
  *
- * Middleware usage:
  * @example
  * ```typescript
  * import middy from '@middy/core';
@@ -48,7 +46,8 @@ type TracerOptions = {
  *  .use(captureLambdaHandler(tracer, { captureResponse: false }));
  * ```
  *
- * Decorator usage:
+ * **Decorator usage**
+ *
  * @example
  * ```typescript
  * const tracer = new Tracer();
@@ -61,6 +60,8 @@ type TracerOptions = {
  * const handlerClass = new Lambda();
  * export const handler = handlerClass.handler.bind(handlerClass);
  * ```
+ *
+ * @property captureResponse - Whether to capture the Lambda handler response as subsegment metadata (default: true)
  */
 type CaptureLambdaHandlerOptions = {
   captureResponse?: boolean;
@@ -69,22 +70,18 @@ type CaptureLambdaHandlerOptions = {
 /**
  * Options for method decorators.
  *
- * Options supported:
- * * `subSegmentName` - (_optional_) - Set a custom name for the subsegment
- * * `captureResponse` - (_optional_) - Disable response serialization as subsegment metadata
- *
  * Usage:
  * @example
  * ```typescript
  * const tracer = new Tracer();
  *
  * class Lambda implements LambdaInterface {
- *   @tracer.captureMethod({ subSegmentName: 'gettingChargeId', captureResponse: false })
+ *   ⁣@tracer.captureMethod({ subSegmentName: 'gettingChargeId', captureResponse: false })
  *   private getChargeId(): string {
  *     return 'foo bar';
  *   }
  *
- *   @tracer.captureLambdaHandler({ captureResponse: false })
+ *   ⁣@tracer.captureLambdaHandler({ captureResponse: false })
  *   public async handler(_event: any, _context: any): Promise<void> {
  *     this.getChargeId();
  *   }
@@ -93,6 +90,9 @@ type CaptureLambdaHandlerOptions = {
  * const handlerClass = new Lambda();
  * export const handler = handlerClass.handler.bind(handlerClass);
  * ```
+ *
+ * @property subSegmentName - (_optional_) - Set a custom name for the subsegment
+ * @property captureResponse - (_optional_) - Disable response serialization as subsegment metadata (default: true)
  */
 type CaptureMethodOptions = {
   subSegmentName?: string;

packages/tracer/tests/e2e/decorator.test.ts

@@ -88,7 +88,7 @@ describe('Tracer E2E tests, decorator instrumentation', () => {
     }
   });
 
-  it('should generate all trace data correctly', async () => {
+  it('should generate all trace data correctly', () => {
     // Assess
     const mainSubsegment = traceData[0];
     const { subsegments, annotations, metadata } = mainSubsegment;

packages/tracer/tests/e2e/manual.test.ts

@@ -85,7 +85,7 @@ describe('Tracer E2E tests, manual instantiation', () => {
     }
   });
 
-  it('should generate all trace data correctly', async () => {
+  it('should generate all trace data correctly', () => {
     // Assess
     const mainSubsegment = traceData[0];
     const { subsegments, annotations, metadata } = mainSubsegment;

packages/tracer/tests/helpers/mockRequests.ts

@@ -49,7 +49,7 @@ const mockFetch = ({
   });
 
   if (throwError) {
-    const error = new AggregateError('Mock fetch error');
+    const error = new AggregateError([], 'Mock fetch error');
 
     errorChannel.publish({
       request,
@@ -62,8 +62,7 @@ const mockFetch = ({
   const encoder = new TextEncoder();
   const encodedHeaders = [];
   for (const [key, value] of Object.entries(headers ?? {})) {
-    encodedHeaders.push(encoder.encode(key));
-    encodedHeaders.push(encoder.encode(value));
+    encodedHeaders.push(encoder.encode(key), encoder.encode(value));
   }
   responseHeadersChannel.publish({
     request,

packages/tracer/tests/unit/ProviderService.test.ts

@@ -306,7 +306,7 @@ describe('Class: ProviderService', () => {
   });
 
   describe('Method: instrumentFetch', () => {
-    it('subscribes to the diagnostics channel', async () => {
+    it('subscribes to the diagnostics channel', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
 
@@ -319,7 +319,7 @@ describe('Class: ProviderService', () => {
       expect(channel('undici:request:error').hasSubscribers).toBe(true);
     });
 
-    it('traces a successful request', async () => {
+    it('traces a successful request', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -367,7 +367,7 @@ describe('Class: ProviderService', () => {
       );
     });
 
-    it('excludes the content_length header when invalid or not found', async () => {
+    it('excludes the content_length header when invalid or not found', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -406,7 +406,7 @@ describe('Class: ProviderService', () => {
       expect(provider.setSegment).toHaveBeenLastCalledWith(segment);
     });
 
-    it('adds a throttle flag to the segment when the status code is 429', async () => {
+    it('adds a throttle flag to the segment when the status code is 429', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -442,7 +442,7 @@ describe('Class: ProviderService', () => {
       expect(provider.setSegment).toHaveBeenLastCalledWith(segment);
     });
 
-    it('adds an error flag to the segment when the status code is 4xx', async () => {
+    it('adds an error flag to the segment when the status code is 4xx', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -478,7 +478,7 @@ describe('Class: ProviderService', () => {
       expect(provider.setSegment).toHaveBeenLastCalledWith(segment);
     });
 
-    it('adds a fault flag to the segment when the status code is 5xx', async () => {
+    it('adds a fault flag to the segment when the status code is 5xx', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -514,7 +514,7 @@ describe('Class: ProviderService', () => {
       expect(provider.setSegment).toHaveBeenLastCalledWith(segment);
     });
 
-    it('skips the segment creation when the request has no origin', async () => {
+    it('skips the segment creation when the request has no origin', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -531,7 +531,7 @@ describe('Class: ProviderService', () => {
       expect(provider.setSegment).toHaveBeenCalledTimes(0);
     });
 
-    it('does not add any path to the segment when the request has no path', async () => {
+    it('does not add any path to the segment when the request has no path', () => {
       // Prepare
       const provider: ProviderService = new ProviderService();
       const segment = new Subsegment('## dummySegment');
@@ -564,7 +564,7 @@ describe('Class: ProviderService', () => {
     });
   });
 
-  it('closes the segment and adds a fault flag when the connection fails', async () => {
+  it('closes the segment and adds a fault flag when the connection fails', () => {
     // Prepare
     const provider: ProviderService = new ProviderService();
     const segment = new Subsegment('## dummySegment');
@@ -595,7 +595,7 @@ describe('Class: ProviderService', () => {
     expect(provider.setSegment).toHaveBeenLastCalledWith(segment);
   });
 
-  it('forwards the correct sampling decision in the request header', async () => {
+  it('forwards the correct sampling decision in the request header', () => {
     // Prepare
     const provider: ProviderService = new ProviderService();
     const segment = new Subsegment('## dummySegment');