feat(ALL): Use optional callback LambdaInterface for decorator (#397)

* feat(metrics): Use optional callback LambdaInterface for decorator

* feat(logger): Use optional callback LambdaInterface for decorator

* feat(tracer): Use optional callback LambdaInterface for decorator

Co-authored-by: Andrea Amorosi <[email protected]>

Author: flochaz

Diff for: packages/logger/npm-shrinkwrap.json

@@ -63,7 +63,7 @@
     "url": "https://github.com/awslabs/aws-lambda-powertools-typescript/issues"
   },
   "dependencies": {
-    "@aws-lambda-powertools/commons": "^0.0.2",
+    "@aws-lambda-powertools/commons": "^0.2.0-beta.18",
     "@middy/core": "^2.5.3",
     "@types/aws-lambda": "^8.10.72",
     "lodash": "^4.17.21",

Diff for: packages/logger/package.json

@@ -1,4 +1,4 @@
-import { LambdaInterface } from '@aws-lambda-powertools/commons';
+import { AsyncHandler, LambdaInterface, SyncHandler } from '@aws-lambda-powertools/commons';
 import { Handler } from 'aws-lambda';
 import { ConfigServiceInterface } from '../config';
 import { LogFormatterInterface } from '../formatter';
@@ -55,8 +55,8 @@ type LogItemExtraInput = Array<Error | LogAttributes | unknown>;
 type HandlerMethodDecorator = (
   target: LambdaInterface,
   propertyKey: string | symbol,
-  descriptor: TypedPropertyDescriptor<Handler>
-) => TypedPropertyDescriptor<Handler> | void;
+  descriptor: TypedPropertyDescriptor<SyncHandler<Handler>> | TypedPropertyDescriptor<AsyncHandler<Handler>>
+) => void;
 
 export {
   ClassThatLogs,

Diff for: packages/logger/src/types/Logger.ts

@@ -642,6 +642,51 @@ describe('Class: Logger', () => {
 
     });
 
+    test('when used as decorator on an async handler without context, it returns a function that captures Lambda\'s context information and adds it in the printed logs', async () => {
+
+      // Prepare
+      const expectedReturnValue = 'Lambda invoked!';
+      const logger = new Logger();
+      class LambdaFunction implements LambdaInterface {
+
+        @logger.injectLambdaContext()
+        public async handler<TEvent>(_event: TEvent, _context: Context): Promise<string> {
+          logger.info('This is an INFO log with some context');
+
+          return expectedReturnValue;
+        }
+      }
+
+      // Act
+      logger.info('An INFO log without context!');
+      const actualResult = await new LambdaFunction().handler(dummyEvent, dummyContext);
+
+      // Assess
+
+      expect(actualResult).toEqual(expectedReturnValue);
+      expect(console['info']).toBeCalledTimes(2);
+      expect(console['info']).toHaveBeenNthCalledWith(1, JSON.stringify({
+        level: 'INFO',
+        message: 'An INFO log without context!',
+        service: 'hello-world',
+        timestamp: '2016-06-20T12:08:10.000Z',
+        xray_trace_id: 'abcdef123456abcdef123456abcdef123456',
+      }));
+      expect(console['info']).toHaveBeenNthCalledWith(2, JSON.stringify({
+        cold_start: true,
+        function_arn: 'arn:aws:lambda:eu-central-1:123456789012:function:foo-bar-function',
+        function_memory_size: 128,
+        function_name: 'foo-bar-function',
+        function_request_id: 'c6af9ac6-7b61-11e6-9a41-93e812345678',
+        level: 'INFO',
+        message: 'This is an INFO log with some context',
+        service: 'hello-world',
+        timestamp: '2016-06-20T12:08:10.000Z',
+        xray_trace_id: 'abcdef123456abcdef123456abcdef123456',
+      }));
+
+    });
+
   });
 
   describe('Method: setColdStartValue', () => {