feat(logger): add removeKeys functionality

Author: saragerion

Diff for: docs/core/logger.md

@@ -200,9 +200,12 @@ You can append additional persistent keys and values in the logs generated durin
 * Via the Logger's `appendKeys` method, for all log items generated after calling this method
 * Passing them in the Logger's constructor
 
+To remove the keys you added, you can use the `removeKeys` method.
+
+
 === "handler.ts"
 
-    ```typescript hl_lines="5-12 16-23"
+    ```typescript hl_lines="5-13 17-25 30"
     import { Logger } from '@aws-lambda-powertools/logger';
 
     // Add persistent log keys via the constructor
@@ -213,7 +216,8 @@ You can append additional persistent keys and values in the logs generated durin
             logger: {
                 name: '@aws-lambda-powertools/logger',
                 version: '0.0.1',
-            }
+            },
+            extra_key: "some-value"
         }
     });
 
@@ -224,10 +228,14 @@ You can append additional persistent keys and values in the logs generated durin
     //     logger: {
     //         name: '@aws-lambda-powertools/logger',
     //         version: '0.0.1',
-    //     }
+    //     },
+    //     extra_key: "some-value"
     // });    
 
     export const handler = async (_event: any, _context: any): Promise<unknown> => {
+
+        // If you don't want to log the "extra_key" attribute in your logs, you can remove it
+        logger.removeKeys(["extra_key"])
 
         // This info log will print all extra custom attributes added above
         // Extra attributes: logger object with name and version of the logger library, awsAccountId, awsRegion
@@ -271,6 +279,7 @@ You can append additional persistent keys and values in the logs generated durin
     }
     ```
 
+
 !!! tip "Logger will automatically ignore any key with an `undefined` value"
 
 ### Appending additional data to a single log item

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

@@ -178,6 +178,20 @@ class Logger extends Utility implements ClassThatLogs {
     merge(this.persistentLogAttributes, attributes);
   }
 
+  /**
+   * It removes attributes based on provided keys to all log items generated by this Logger instance.
+   *
+   * @param {string[]} keys
+   * @returns {void}
+   */
+  public removePersistentLogAttributes(keys: string[]): void {
+    keys.forEach((key) => {
+      if(this.persistentLogAttributes && key in this.persistentLogAttributes) {
+        delete this.persistentLogAttributes[key];
+      }
+    })
+  }
+
   /**
    * Alias for addPersistentLogAttributes.
    *
@@ -188,6 +202,16 @@ class Logger extends Utility implements ClassThatLogs {
     this.addPersistentLogAttributes(attributes);
   }
 
+  /**
+   * Alias for removePersistentLogAttributes.
+   *
+   * @param {string[]} keys
+   * @returns {void}
+   */
+  public removeKeys(keys: string[]): void {
+    this.removePersistentLogAttributes(keys);
+  }
+
   /**
    * It creates a separate Logger instance, identical to the current one
    * It's possible to overwrite the new instance options by passing them.

Diff for: packages/logger/tests/e2e/basicFeatures.middy.test.FunctionCode.ts

@@ -4,6 +4,8 @@ import middy from '@middy/core';
 
 const PERSISTENT_KEY = process.env.PERSISTENT_KEY;
 const PERSISTENT_VALUE = process.env.PERSISTENT_VALUE;
+const REMOVABLE_KEY = process.env.REMOVABLE_KEY;
+const REMOVABLE_VALUE = process.env.REMOVABLE_VALUE;
 const ERROR_MSG = process.env.ERROR_MSG || 'error';
 const SINGLE_LOG_ITEM_KEY = process.env.SINGLE_LOG_ITEM_KEY;
 const SINGLE_LOG_ITEM_VALUE = process.env.SINGLE_LOG_ITEM_VALUE;
@@ -13,14 +15,16 @@ const ARBITRARY_OBJECT_DATA = process.env.ARBITRARY_OBJECT_DATA;
 const logger = new Logger({
   persistentLogAttributes: {
     [PERSISTENT_KEY]: PERSISTENT_VALUE,
+    [REMOVABLE_KEY]: REMOVABLE_VALUE,
   },
 });
 
 const testFunction = async (event: APIGatewayProxyEvent, context: Context): Promise<{requestId: string}> => {
   // Test feature 1: Log level filtering
   // Test feature 2: Context data
-  // Test feature 3: Persistent additional log keys and value
+  // Test feature 3: Add and remove persistent additional log keys and value
   // Test feature 4: X-Ray Trace ID injection
+  logger.removeKeys([ REMOVABLE_KEY ]);
   logger.debug('##### This should not appear');
   logger.info('This is an INFO log with context and persistent key');
 

Diff for: packages/logger/tests/e2e/basicFeatures.middy.test.ts

@@ -43,6 +43,8 @@ const lambdaFunctionCodeFile = 'basicFeatures.middy.test.FunctionCode.ts';
 // Text to be used by Logger in the Lambda function
 const PERSISTENT_KEY = 'persistentKey';
 const PERSISTENT_VALUE = `a persistent value that will be put in every log ${uuid}`;
+const REMOVABLE_KEY = "removableKey";
+const REMOVABLE_VALUE = "a persistent value that will be removed and not displayed in any log ${uuid}";
 const SINGLE_LOG_ITEM_KEY = `keyForSingleLogItem${uuid}`;
 const SINGLE_LOG_ITEM_VALUE = `a value for a single log item${uuid}`;
 const ERROR_MSG = `error-${uuid}`;
@@ -72,6 +74,8 @@ describe(`logger E2E tests basic functionalities (middy) for runtime: ${runtime}
         // Text to be used by Logger in the Lambda function
         PERSISTENT_KEY,
         PERSISTENT_VALUE,
+        REMOVABLE_KEY,
+        REMOVABLE_VALUE,
         SINGLE_LOG_ITEM_KEY,
         SINGLE_LOG_ITEM_VALUE,
         ERROR_MSG,
@@ -147,6 +151,14 @@ describe(`logger E2E tests basic functionalities (middy) for runtime: ${runtime}
         expect(message).toContain(`"${PERSISTENT_KEY}":"${PERSISTENT_VALUE}"`);
       }
     }, TEST_CASE_TIMEOUT);
+
+    it('should not contain persistent keys that were removed on runtime', async () => {
+      const logMessages = invocationLogs[0].getFunctionLogs();
+
+      for (const message of logMessages) {
+        expect(message).not.toContain(`"${REMOVABLE_KEY}":"${REMOVABLE_VALUE}"`);
+      }
+    }, TEST_CASE_TIMEOUT);
   });
 
   describe('X-Ray Trace ID injection', () => {

Diff for: packages/logger/tests/unit/Logger.test.ts

@@ -638,7 +638,7 @@ describe('Class: Logger', () => {
 
   describe('Method: appendKeys', () => {
 
-    test('when called, populates the logger\'s propriety persistentLogAttributes ', () => {
+    test('when called, it populates the logger\'s propriety persistentLogAttributes ', () => {
 
       // Prepare
       const logger = new Logger();
@@ -704,6 +704,97 @@ describe('Class: Logger', () => {
     });
   });
 
+  describe('Method: removeKeys', () => {
+
+    test('when called, it removes keys from the logger\'s propriety persistentLogAttributes', () => {
+
+      // Prepare
+      const logger = new Logger();
+      logger.appendKeys({
+        aws_account_id: '123456789012',
+        aws_region: 'eu-west-1',
+        logger: {
+          name: 'aws-lambda-powertool-typescript',
+          version: '0.2.4',
+        },
+      });
+
+      // Act
+      logger.removeKeys(["aws_account_id", "aws_region"]);
+
+      // Assess
+      expect(logger).toEqual(expect.objectContaining({
+        persistentLogAttributes: {
+          logger: {
+            name: 'aws-lambda-powertool-typescript',
+            version: '0.2.4',
+          },
+        },
+      }));
+    });
+
+    test('when called with non-existing keys, the logger\'s propriety persistentLogAttributes is not mutated and it does not throw an error', () => {
+
+      // Prepare
+      const logger = new Logger();
+      logger.appendKeys({
+        aws_account_id: '123456789012',
+        aws_region: 'eu-west-1',
+        logger: {
+          name: 'aws-lambda-powertool-typescript',
+          version: '0.2.4',
+        },
+      });
+      const loggerBeforeKeysAreRemoved = { ...logger };
+
+      // Act
+      logger.removeKeys(["not_existing_key"]);
+
+      // Assess
+      expect(logger).toEqual(loggerBeforeKeysAreRemoved);
+      expect(logger).toEqual(expect.objectContaining({
+        persistentLogAttributes: {
+          aws_account_id: '123456789012',
+          aws_region: 'eu-west-1',
+          logger: {
+            name: 'aws-lambda-powertool-typescript',
+            version: '0.2.4',
+          },
+        },
+      }));
+    });
+
+  });
+
+  test('when called multiple times with the same keys, the outcome is the same', () => {
+
+    // Prepare
+    const logger = new Logger();
+    logger.appendKeys({
+      aws_account_id: '123456789012',
+      aws_region: 'eu-west-1',
+      logger: {
+        name: 'aws-lambda-powertool-typescript',
+        version: '0.2.4',
+      },
+    });
+
+    // Act
+    logger.removeKeys(["aws_account_id", "aws_region"]);
+    logger.removeKeys(["aws_account_id", "aws_region"]);
+
+    // Assess
+    expect(logger).toEqual(expect.objectContaining({
+      persistentLogAttributes: {
+        logger: {
+          name: 'aws-lambda-powertool-typescript',
+          version: '0.2.4',
+        },
+      },
+    }));
+
+  });
+
   describe('Method: injectLambdaContext', () => {
 
     beforeEach(() => {