feat(api): Optionally suppress warning about logger being overwritten

api/CHANGELOG.md

@@ -2,6 +2,12 @@
 
 All notable changes to this project will be documented in this file.
 
+## Unreleased
+
+### Features
+
+* Optionally suppress warning about logger being overwritten ([#3366](https://www.github.com/open-telemetry/opentelemetry-js-api/pull/3366))
+
 ## [1.2.0](https://www.github.com/open-telemetry/opentelemetry-js-api/compare/v1.1.0...v1.2.0) (2022-08-09)
 
 ### Features

api/src/api/diag.ts

@@ -30,6 +30,11 @@ import {
 
 const API_NAME = 'diag';
 
+interface LoggerOptions {
+  logLevel?: DiagLogLevel;
+  suppressOverrideMessage?: boolean;
+}
+
 /**
  * Singleton object which represents the entry point to the OpenTelemetry internal
  * diagnostic API
@@ -65,35 +70,6 @@ export class DiagAPI implements DiagLogger {
 
     // DiagAPI specific functions
 
-    self.setLogger = (
-      logger: DiagLogger,
-      logLevel: DiagLogLevel = DiagLogLevel.INFO
-    ) => {
-      if (logger === self) {
-        // There isn't much we can do here.
-        // Logging to the console might break the user application.
-        // Try to log to self. If a logger was previously registered it will receive the log.
-        const err = new Error(
-          'Cannot use diag as the logger for itself. Please use a DiagLogger implementation like ConsoleDiagLogger or a custom implementation'
-        );
-        self.error(err.stack ?? err.message);
-        return false;
-      }
-
-      const oldLogger = getGlobal('diag');
-      const newLogger = createLogLevelDiagLogger(logLevel, logger);
-      // There already is an logger registered. We'll let it know before overwriting it.
-      if (oldLogger) {
-        const stack = new Error().stack ?? '<failed to generate stacktrace>';
-        oldLogger.warn(`Current logger will be overwritten from ${stack}`);
-        newLogger.warn(
-          `Current logger will overwrite one already registered from ${stack}`
-        );
-      }
-
-      return registerGlobal('diag', newLogger, self, true);
-    };
-
     self.disable = () => {
       unregisterGlobal(API_NAME, self);
     };
@@ -117,7 +93,47 @@ export class DiagAPI implements DiagLogger {
    * @param logLevel - [Optional] The DiagLogLevel used to filter logs sent to the logger. If not provided it will default to INFO.
    * @returns true if the logger was successfully registered, else false
    */
-  public setLogger!: (logger: DiagLogger, logLevel?: DiagLogLevel) => boolean;
+  public setLogger(logger: DiagLogger, logLevel?: DiagLogLevel): boolean;
+  /**
+  * Set the global DiagLogger and DiagLogLevel.
+  * If a global diag logger is already set, this will override it.
+  *
+  * @param logger - [Optional] The DiagLogger instance to set as the default logger.
+  * @param options - [Optional] And object which can contain `logLevel: DiagLogLevel` used to filter logs sent to the logger. If not provided it will default to INFO. The object may also contain `suppressOverrideMessage: boolean` which will suppress the warning normally logged when a logger is already registered.
+  * @returns true if the logger was successfully registered, else false
+  */
+  public setLogger(logger: DiagLogger, options?: LoggerOptions): boolean;
+  public setLogger(logger: DiagLogger, optionsOrLogLevel: DiagLogLevel | LoggerOptions = { logLevel: DiagLogLevel.INFO }) {
+    if (logger === this) {
+      // There isn't much we can do here.
+      // Logging to the console might break the user application.
+      // Try to log to self. If a logger was previously registered it will receive the log.
+      const err = new Error(
+        'Cannot use diag as the logger for itself. Please use a DiagLogger implementation like ConsoleDiagLogger or a custom implementation'
+      );
+      this.error(err.stack ?? err.message);
+      return false;
+    }
+
+    if (typeof optionsOrLogLevel === 'number') {
+      optionsOrLogLevel = {
+        logLevel: optionsOrLogLevel,
+      }
+    }
+
+    const oldLogger = getGlobal('diag');
+    const newLogger = createLogLevelDiagLogger(optionsOrLogLevel.logLevel ?? DiagLogLevel.INFO, logger);
+    // There already is an logger registered. We'll let it know before overwriting it.
+    if (oldLogger && !optionsOrLogLevel.suppressOverrideMessage) {
+      const stack = new Error().stack ?? '<failed to generate stacktrace>';
+      oldLogger.warn(`Current logger will be overwritten from ${stack}`);
+      newLogger.warn(
+        `Current logger will overwrite one already registered from ${stack}`
+      );
+    }
+
+    return registerGlobal('diag', newLogger, this, true);
+  }
   /**
    *
    */