feat: adopted Utility class & updated unit tests

Author: dreamorosi

packages/logger/src/Logger.ts

@@ -1,4 +1,5 @@
 import type { Context } from 'aws-lambda';
+import { Utility } from '@aws-lambda-powertools/commons';
 import { LogFormatterInterface, PowertoolLogFormatter } from './formatter';
 import { LogItem } from './log';
 import cloneDeep from 'lodash.clonedeep';
@@ -104,11 +105,7 @@ import type {
  * @implements {ClassThatLogs}
  * @see https://awslabs.github.io/aws-lambda-powertools-typescript/latest/core/logger/
  */
-class Logger implements ClassThatLogs {
-
-  private static coldStart?: boolean = undefined;
-
-  private static coldStartEvaluated: boolean = false;
+class Logger extends Utility implements ClassThatLogs {
 
   private customConfigService?: ConfigServiceInterface;
 
@@ -141,6 +138,8 @@ class Logger implements ClassThatLogs {
    * @param {LoggerOptions} options
    */
   public constructor(options: LoggerOptions = {}) {
+    super();
+
     this.setOptions(options);
   }
 
@@ -152,10 +151,9 @@ class Logger implements ClassThatLogs {
    * @returns {void}
    */
   public addContext(context: Context): void {
-    Logger.evaluateColdStartOnce();
     const lambdaContext: Partial<LambdaFunctionContext> = {
       invokedFunctionArn: context.invokedFunctionArn,
-      coldStart: Logger.getColdStartValue(),
+      coldStart: this.getColdStart(),
       awsRequestId: context.awsRequestId,
       memoryLimitInMB: Number(context.memoryLimitInMB),
       functionName: context.functionName,
@@ -220,38 +218,6 @@ class Logger implements ClassThatLogs {
     this.processLogItem('ERROR', input, extraInput);
   }
 
-  /**
-   * It evaluates whether the current Lambda function invocation has a cold start or not.
-   *
-   * @static
-   * @returns {void}
-   */
-  public static evaluateColdStartOnce(): void {
-    if (!Logger.getColdStartEvaluatedValue()) {
-      Logger.evaluateColdStart();
-    }
-  }
-
-  /**
-   * It returns a boolean value which is true if the current Lambda function cold start has been already evaluated, false otherwise.
-   *
-   * @static
-   * @returns {boolean}
-   */
-  public static getColdStartEvaluatedValue(): boolean {
-    return Logger.coldStartEvaluated;
-  }
-
-  /**
-   * It returns an optional boolean value, true if the current Lambda function invocation has a cold start, false otherwise.
-   *
-   * @static
-   * @returns {boolean | undefined}
-   */
-  public static getColdStartValue(): boolean | undefined {
-    return Logger.coldStart;
-  }
-
   /**
    * It returns a boolean value, if true all the logs will be printed.
    *
@@ -305,30 +271,6 @@ class Logger implements ClassThatLogs {
     this.setLogsSampled();
   }
 
-  /**
-   * It sets the value of a flag static propriety that tracks whether
-   * the cold start evaluation already took place.
-   *
-   * @param {boolean} value
-   * @static
-   * @returns {void}
-   */
-  public static setColdStartEvaluatedValue(value: boolean): void {
-    Logger.coldStartEvaluated = value;
-  }
-
-  /**
-   * It sets the value of a flag static propriety that tracks whether
-   * the current Lambda invocation experienced a cold start.
-   *
-   * @static
-   * @param {boolean | undefined} value
-   * @returns {void}
-   */
-  public static setColdStartValue(value: boolean | undefined): void {
-    Logger.coldStart = value;
-  }
-
   /**
    * It sets the user-provided sample rate value.
    *
@@ -402,27 +344,6 @@ class Logger implements ClassThatLogs {
     return logItem;
   }
 
-  /**
-   * It evaluates whether the current Lambda invocation experienced a
-   * cold start.
-   *
-   * @private
-   * @static
-   * @returns {void}
-   */
-  private static evaluateColdStart(): void {
-    const coldStartValue = Logger.getColdStartValue();
-    if (typeof coldStartValue === 'undefined') {
-      Logger.setColdStartValue(true);
-    } else if (coldStartValue) {
-      Logger.setColdStartValue(false);
-    } else {
-      Logger.setColdStartValue(false);
-    }
-
-    Logger.setColdStartEvaluatedValue(true);
-  }
-
   /**
    * It returns the custom config service, an abstraction used to fetch environment variables.
    *

packages/logger/tests/unit/Logger.test.ts

@@ -28,8 +28,6 @@ const consoleSpy = {
 describe('Class: Logger', () => {
 
   beforeEach(() => {
-    Logger.setColdStartValue(undefined);
-    Logger.setColdStartEvaluatedValue(false);
     consoleSpy['debug'].mockClear();
     consoleSpy['info'].mockClear();
     consoleSpy['warn'].mockClear();
@@ -462,6 +460,7 @@ describe('Class: Logger', () => {
 
       // Assess
       expect(logger).toEqual({
+        coldStart: false, // This is now false because the `coldStart` attribute has been already accessed once by the `addContext` method
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -525,79 +524,6 @@ describe('Class: Logger', () => {
     });
   });
 
-  describe('Method: createChild', () => {
-
-    test('when called, creates a distinct clone of the original logger instance', () => {
-
-      // Prepare
-      const logger = new Logger();
-
-      // Act
-      const childLogger = logger.createChild({
-        logLevel: 'ERROR',
-      });
-
-      // Assess
-      expect(logger).toEqual(expect.objectContaining({
-        logLevel: 'DEBUG',
-      }));
-      expect(childLogger).toBeInstanceOf(Logger);
-      expect(childLogger).toEqual(expect.objectContaining({
-        logLevel: 'ERROR',
-      }));
-    });
-
-  });
-
-  describe('Method: evaluateColdStartOnce', () => {
-
-    test('when called during the first invocation (cold start), it populates the logger\'s PowertoolLogData object with coldstart set to true', () => {
-
-      // Prepare
-      // This value is undefined at the beginning of the first invocation
-      Logger.setColdStartValue(undefined);
-
-      // Act
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-
-      // Assess
-      expect(Logger.getColdStartValue()).toEqual(true);
-    });
-
-    test('when called during the SECOND invocation (warm start), it populates the logger\'s PowertoolLogData object with coldstart set to false', () => {
-
-      // Prepare
-      // This value is set to true at the beginning of the second invocation
-      Logger.setColdStartValue(true);
-
-      // Act
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-
-      // Assess
-      expect(Logger.getColdStartValue()).toEqual(false);
-    });
-
-    test('when called during the THIRD invocation (warm start), it populates the logger\'s PowertoolLogData object with coldstart set to false', () => {
-
-      // Prepare
-      // This value is set to false at the beginning of the third invocation
-      Logger.setColdStartValue(false);
-
-      // Act
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-      Logger.evaluateColdStartOnce();
-
-      // Assess
-      expect(Logger.getColdStartValue()).toEqual(false);
-    });
-
-  });
-
   describe('Method: injectLambdaContext', () => {
 
     beforeEach(() => {
@@ -736,29 +662,6 @@ describe('Class: Logger', () => {
 
   });
 
-  describe('Method: setColdStartValue', () => {
-
-    test('when called, it sets the value of the static variable coldStart in the same file', async () => {
-
-      // Act
-      Logger.setColdStartValue(undefined);
-      const undefinedValue = Logger.getColdStartValue();
-
-      Logger.setColdStartValue(true);
-      const trueValue = Logger.getColdStartValue();
-
-      Logger.setColdStartValue(false);
-      const falseValue = Logger.getColdStartValue();
-
-      // Assess
-      expect(undefinedValue).toBe(undefined);
-      expect(trueValue).toBe(true);
-      expect(falseValue).toBe(false);
-
-    });
-
-  });
-
   describe('Method: refreshSampleRateCalculation', () => {
 
     test('when called, it recalculates whether the current Lambda invocation\'s logs will be printed or not', () => {
@@ -815,6 +718,7 @@ describe('Class: Logger', () => {
       expect(parentLogger === childLoggerWithErrorLogLevel).toBe(false);
 
       expect(parentLogger).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -837,6 +741,7 @@ describe('Class: Logger', () => {
       });
 
       expect(childLoggerWithPermanentAttributes).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -861,6 +766,7 @@ describe('Class: Logger', () => {
       });
 
       expect(childLoggerWithSampleRateEnabled).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -883,6 +789,7 @@ describe('Class: Logger', () => {
       });
 
       expect(childLoggerWithErrorLogLevel).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),

packages/logger/tests/unit/helpers.test.ts

@@ -73,6 +73,7 @@ describe('Helper: createLogger function', () => {
       // Assess
       expect(logger).toBeInstanceOf(Logger);
       expect(logger).toEqual({
+        coldStart: true,
         customConfigService: expect.any(EnvironmentVariablesService),
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -111,6 +112,7 @@ describe('Helper: createLogger function', () => {
       // Assess
       expect(logger).toBeInstanceOf(Logger);
       expect(logger).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),
@@ -233,6 +235,7 @@ describe('Helper: createLogger function', () => {
       // Assess
       expect(logger).toBeInstanceOf(Logger);
       expect(logger).toEqual({
+        coldStart: true,
         customConfigService: undefined,
         envVarsService: expect.any(EnvironmentVariablesService),
         logFormatter: expect.any(PowertoolLogFormatter),