feat(logger): disable logs while testing with jest --silent in dev …

…env (#1165) * feat(logger): disable logs while testing with jest --silent in dev env * refactor(logger): rename method * docs(logger): add testing section with jest --silent option, which is also suppresses logs (#1165) * Update docs/core/logger.md Co-authored-by: Andrea Amorosi <[email protected]> * test(logger): add test for setConsole() method * test(logger): add comment for assertion * docs(logger): add an example of using POWERTOOLS_DEV with jest --silent * Update packages/logger/src/Logger.ts Co-authored-by: Andrea Amorosi <[email protected]> Co-authored-by: Andrea Amorosi <[email protected]>
aws-powertools · Nov 15, 2022 · 6f0c307 · 6f0c307
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diff --git a/docs/core/logger.md b/docs/core/logger.md
@@ -971,3 +971,11 @@ This is a Jest sample that provides the minimum information necessary for Logger
 
 !!! tip
     If you don't want to declare your own dummy Lambda Context, you can use [`ContextExamples.helloworldContext`](https://github.com/awslabs/aws-lambda-powertools-typescript/blob/main/packages/commons/src/samples/resources/contexts/hello-world.ts#L3-L16) from [`@aws-lambda-powertools/commons`](https://www.npmjs.com/package/@aws-lambda-powertools/commons).
+
+### Suppress logs with Jest
+
+When unit testing your code with [Jest](https://jestjs.io) you can use the `POWERTOOLS_DEV` environment variable in conjunction with the Jest `--silent` CLI option to suppress logs from Logger.
+
+```bash title="Disabling logs while testing with Jest"
+export POWERTOOLS_DEV=true && npx jest --silent
+```
diff --git a/packages/logger/src/Logger.ts b/packages/logger/src/Logger.ts
@@ -113,7 +113,8 @@ import type {
  */
 class Logger extends Utility implements ClassThatLogs {
 
-  private console = new Console({ stdout: process.stdout, stderr: process.stderr });
+  // console is initialized in the constructor in setOptions()
+  private console!: Console;
 
   private customConfigService?: ConfigServiceInterface;
 
@@ -572,7 +573,7 @@ class Logger extends Utility implements ClassThatLogs {
 
     return <number> this.powertoolLogData.sampleRateValue;
   }
-
+  
   /**
    * It returns true if the provided log level is valid.
    *
@@ -640,6 +641,21 @@ class Logger extends Utility implements ClassThatLogs {
     };
   }
 
+  /**
+   * It initializes console property as an instance of the internal version of Console() class (PR #748)
+   * or as the global node console if the `POWERTOOLS_DEV' env variable is set and has truthy value.
+   *
+   * @private
+   * @returns {void}
+   */
+  private setConsole(): void {
+    if (!this.getEnvVarsService().isDevMode()) {
+      this.console = new Console({ stdout: process.stdout, stderr: process.stderr });
+    } else {
+      this.console = console;
+    }
+  }
+
   /**
    * Sets the Logger's customer config service instance, which will be used
    * to fetch environment variables.
@@ -697,7 +713,7 @@ class Logger extends Utility implements ClassThatLogs {
    * @returns {void}
    */
   private setLogIndentation(): void {
-    if (this.getEnvVarsService().getDevMode()) {
+    if (this.getEnvVarsService().isDevMode()) {
       this.logIndentation = LogJsonIndent.PRETTY;
     }
   }
@@ -764,6 +780,8 @@ class Logger extends Utility implements ClassThatLogs {
     } = options;
 
     this.setEnvVarsService();
+    // order is important, it uses EnvVarsService()
+    this.setConsole();
     this.setCustomConfigService(customConfigService);
     this.setLogLevel(logLevel);
     this.setSampleRateValue(sampleRateValue);

diff --git a/packages/logger/src/config/ConfigServiceInterface.ts b/packages/logger/src/config/ConfigServiceInterface.ts
@@ -22,13 +22,6 @@ interface ConfigServiceInterface {
    */
   getCurrentEnvironment(): string
 
-  /**
-   * It returns the value of the POWERTOOLS_DEV environment variable.
-   *
-   * @returns {boolean}
-   */
-  getDevMode(): boolean
-
   /**
    * It returns the value of the POWERTOOLS_LOGGER_LOG_EVENT environment variable.
    *
@@ -57,6 +50,13 @@ interface ConfigServiceInterface {
    */
   getServiceName(): string
 
+  /**
+   * It returns the value of the POWERTOOLS_DEV environment variable.
+   *
+   * @returns {boolean}
+   */
+  isDevMode(): boolean
+
   /**
    * It returns true if the string value represents a boolean true value.
    *

diff --git a/packages/logger/src/config/EnvironmentVariablesService.ts b/packages/logger/src/config/EnvironmentVariablesService.ts
@@ -46,17 +46,6 @@ class EnvironmentVariablesService extends CommonEnvironmentVariablesService impl
     return this.get(this.currentEnvironmentVariable);
   }
 
-  /**
-   * It returns the value of the POWERTOOLS_DEV environment variable.
-   *
-   * @returns {boolean}
-   */
-  public getDevMode(): boolean {
-    const value = this.get(this.devModeVariable);
-
-    return this.isValueTrue(value);
-  }
-
   /**
    * It returns the value of the AWS_LAMBDA_FUNCTION_MEMORY_SIZE environment variable.
    *
@@ -117,6 +106,17 @@ class EnvironmentVariablesService extends CommonEnvironmentVariablesService impl
     return (value && value.length > 0) ? Number(value) : undefined;
   }
 
+  /**
+   * It returns true if the POWERTOOLS_DEV environment variable is set to truthy value.
+   *
+   * @returns {boolean}
+   */
+  public isDevMode(): boolean {
+    const value = this.get(this.devModeVariable);
+
+    return this.isValueTrue(value);
+  }
+
   /**
    * It returns true if the string value represents a boolean true value.
    *

diff --git a/packages/logger/tests/unit/Logger.test.ts b/packages/logger/tests/unit/Logger.test.ts
@@ -1239,6 +1239,7 @@ describe('Class: Logger', () => {
     test('when called, it returns a DISTINCT clone of the logger instance', () => {
 
       // Prepare
+      const INDENTATION = LogJsonIndent.COMPACT;
       const parentLogger = new Logger();
 
       // Act
@@ -1257,7 +1258,10 @@ describe('Class: Logger', () => {
 
       // Assess
       expect(parentLogger === childLogger).toBe(false);
-      expect(parentLogger).toEqual(childLogger);
+      expect(childLogger).toEqual({
+        ...parentLogger,
+        console: expect.any(Console),
+      });
       expect(parentLogger === childLoggerWithPermanentAttributes).toBe(false);
       expect(parentLogger === childLoggerWithSampleRateEnabled).toBe(false);
       expect(parentLogger === childLoggerWithErrorLogLevel).toBe(false);
@@ -1269,7 +1273,7 @@ describe('Class: Logger', () => {
         defaultServiceName: 'service_undefined',
         envVarsService: expect.any(EnvironmentVariablesService),
         logEvent: false,
-        logIndentation: 0,
+        logIndentation: INDENTATION,
         logFormatter: expect.any(PowertoolLogFormatter),
         logLevel: 'DEBUG',
         logLevelThresholds: {
@@ -1295,7 +1299,7 @@ describe('Class: Logger', () => {
         defaultServiceName: 'service_undefined',
         envVarsService: expect.any(EnvironmentVariablesService),
         logEvent: false,
-        logIndentation: 0,
+        logIndentation: INDENTATION,
         logFormatter: expect.any(PowertoolLogFormatter),
         logLevel: 'DEBUG',
         logLevelThresholds: {
@@ -1323,7 +1327,7 @@ describe('Class: Logger', () => {
         defaultServiceName: 'service_undefined',
         envVarsService: expect.any(EnvironmentVariablesService),
         logEvent: false,
-        logIndentation: 0,
+        logIndentation: INDENTATION,
         logFormatter: expect.any(PowertoolLogFormatter),
         logLevel: 'DEBUG',
         logLevelThresholds: {
@@ -1349,7 +1353,7 @@ describe('Class: Logger', () => {
         defaultServiceName: 'service_undefined',
         envVarsService: expect.any(EnvironmentVariablesService),
         logEvent: false,
-        logIndentation: 0,
+        logIndentation: INDENTATION,
         logFormatter: expect.any(PowertoolLogFormatter),
         logLevel: 'ERROR',
         logLevelThresholds: {
@@ -1461,4 +1465,27 @@ describe('Class: Logger', () => {
     });
   });
 
-});
+  describe('Method: setConsole()', () => {
+
+    test('When the `POWERTOOLS_DEV` env var is SET console object is set to the global node console otherwise to the instance of the internal version of console', () => {
+
+      // Prepare
+      const logger = new Logger();
+      process.env.POWERTOOLS_DEV = 'true';
+      const devLogger = new Logger();
+
+      // Assess
+      expect(devLogger).toEqual({
+        ...devLogger,
+        console: console,
+      });
+      // since instances of a class are not equal objects,
+      // we assert the opposite – console is not the global node object
+      expect(logger).not.toEqual({
+        ...logger,
+        console: console,
+      });
+    });
+  });
+
+});
diff --git a/packages/logger/tests/unit/config/EnvironmentVariablesService.test.ts b/packages/logger/tests/unit/config/EnvironmentVariablesService.test.ts
@@ -181,7 +181,7 @@ describe('Class: EnvironmentVariablesService', () => {
 
   });
 
-  describe('Method: getDevMode', () => {
+  describe('Method: isDevMode', () => {
 
     test('It returns true if the environment variable POWERTOOLS_DEV is "true"', () => {
 
@@ -190,7 +190,7 @@ describe('Class: EnvironmentVariablesService', () => {
       const service = new EnvironmentVariablesService();
 
       // Act
-      const value = service.getDevMode();
+      const value = service.isDevMode();
 
       // Assess
       expect(value).toEqual(true);
@@ -203,7 +203,7 @@ describe('Class: EnvironmentVariablesService', () => {
       const service = new EnvironmentVariablesService();
 
       // Act
-      const value = service.getDevMode();
+      const value = service.isDevMode();
 
       // Assess
       expect(value).toEqual(false);
@@ -216,7 +216,7 @@ describe('Class: EnvironmentVariablesService', () => {
       const service = new EnvironmentVariablesService();
 
       // Act
-      const value = service.getDevMode();
+      const value = service.isDevMode();
 
       // Assess
       expect(value).toEqual(false);
@@ -229,7 +229,7 @@ describe('Class: EnvironmentVariablesService', () => {
       const service = new EnvironmentVariablesService();
 
       // Act
-      const value = service.getDevMode();
+      const value = service.isDevMode();
 
       // Assess
       expect(value).toEqual(false);

diff --git a/packages/logger/tests/unit/helpers.test.ts b/packages/logger/tests/unit/helpers.test.ts
@@ -314,7 +314,7 @@ describe('Helper: createLogger function', () => {
         getServiceName(): string {
           return 'my-backend-service';
         },
-        getDevMode(): boolean {
+        isDevMode(): boolean {
           return false;
         },
         isValueTrue(): boolean {

diff --git a/packages/logger/tests/unit/middleware/middy.test.ts b/packages/logger/tests/unit/middleware/middy.test.ts
@@ -336,7 +336,7 @@ describe('Middy middleware', () => {
         getServiceName(): string {
           return 'my-backend-service';
         },
-        getDevMode(): boolean {
+        isDevMode(): boolean {
           return false;
         },
         isValueTrue(): boolean {