fix(logger): reset log level after sampling refresh (#2673)

Author: dreamorosi

packages/logger/src/Logger.ts

@@ -194,6 +194,12 @@ class Logger extends Utility implements LoggerInterface {
    * type. We then use this map at log preparation time to pick the last one.
    */
   #keys: Map<string, 'temp' | 'persistent'> = new Map();
+  /**
+   * This is the initial log leval as set during the initialization of the logger.
+   *
+   * We keep this value to be able to reset the log level to the initial value when the sample rate is refreshed.
+   */
+  #initialLogLevel = 12;
 
   /**
    * Log level used by the current instance of Logger.
@@ -976,6 +982,7 @@ class Logger extends Utility implements LoggerInterface {
 
     if (this.isValidLogLevel(constructorLogLevel)) {
       this.logLevel = this.logLevelThresholds[constructorLogLevel];
+      this.#initialLogLevel = this.logLevel;
 
       return;
     }
@@ -984,12 +991,14 @@ class Logger extends Utility implements LoggerInterface {
       ?.toUpperCase();
     if (this.isValidLogLevel(customConfigValue)) {
       this.logLevel = this.logLevelThresholds[customConfigValue];
+      this.#initialLogLevel = this.logLevel;
 
       return;
     }
     const envVarsValue = this.getEnvVarsService()?.getLogLevel()?.toUpperCase();
     if (this.isValidLogLevel(envVarsValue)) {
       this.logLevel = this.logLevelThresholds[envVarsValue];
+      this.#initialLogLevel = this.logLevel;
 
       return;
     }
@@ -1019,6 +1028,10 @@ class Logger extends Utility implements LoggerInterface {
         if (value && randomInt(0, 100) / 100 <= value) {
           this.setLogLevel('DEBUG');
           this.debug('Setting log level to DEBUG due to sampling rate');
+        } else {
+          this.setLogLevel(
+            this.getLogLevelNameFromNumber(this.#initialLogLevel)
+          );
         }
 
         return;

packages/logger/tests/e2e/sampleRate.decorator.test.FunctionCode.ts

@@ -1,5 +1,5 @@
 import { Logger } from '../../src/index.js';
-import type { TestEvent, TestOutput } from '../helpers/types';
+import type { TestEvent, TestOutput } from '../helpers/types.js';
 import type { Context } from 'aws-lambda';
 import type { LambdaInterface } from '@aws-lambda-powertools/commons/types';
 
@@ -9,6 +9,7 @@ const LOG_MSG = process.env.LOG_MSG || 'Hello World';
 const logger = new Logger({
   sampleRateValue: SAMPLE_RATE,
 });
+let firstInvocation = true;
 
 class Lambda implements LambdaInterface {
   private readonly logMsg: string;
@@ -19,9 +20,12 @@ class Lambda implements LambdaInterface {
 
   // Decorate your handler class method
   @logger.injectLambdaContext()
-  // eslint-disable-next-line @typescript-eslint/ban-ts-comment
-  // @ts-ignore
-  public async handler(event: TestEvent, context: Context): TestOutput {
+  public async handler(_event: TestEvent, context: Context): TestOutput {
+    if (firstInvocation) {
+      firstInvocation = false;
+    } else {
+      logger.refreshSampleRateCalculation();
+    }
     this.printLogInAllLevels();
 
     return {

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

@@ -3443,7 +3443,6 @@ describe('Class: Logger', () => {
           logger.refreshSampleRateCalculation();
           if (logger.getLevelName() === 'DEBUG') {
             logLevelChangedToDebug++;
-            logger.setLogLevel('ERROR');
           }
         }