feat: add custom logger support via logger callback option

Author: EmilianoSanchez

src/logger/__tests__/sdkLogger.mock.ts

@@ -6,6 +6,7 @@ export const loggerMock = {
   debug: jest.fn(),
   info: jest.fn(),
   setLogLevel: jest.fn(),
+  setLogger: jest.fn(),
 
   mockClear() {
     this.warn.mockClear();

src/logger/index.ts

@@ -41,6 +41,7 @@ const defaultOptions = {
   prefix: 'splitio',
   logLevel: LogLevels.NONE,
   showLevel: true,
+  logger(formattedMsg: string) { console.log(formattedMsg); }
 };
 
 export class Logger implements ILogger {
@@ -55,6 +56,10 @@ export class Logger implements ILogger {
     this.logLevel = LogLevelIndexes[this.options.logLevel];
   }
 
+  setLogger(logger: (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void) {
+    this.options.logger = logger;
+  }
+
   setLogLevel(logLevel: SplitIO.LogLevel) {
     this.options.logLevel = logLevel;
     this.logLevel = LogLevelIndexes[logLevel];
@@ -86,7 +91,7 @@ export class Logger implements ILogger {
 
     const formattedText = this._generateLogMessage(level, msg);
 
-    console.log(formattedText);
+    this.options.logger(formattedText, level, msg);
   }
 
   private _generateLogMessage(level: SplitIO.LogLevel, text: string) {

src/logger/types.ts

@@ -1,12 +1,15 @@
 import SplitIO from '../../types/splitio';
 
 export interface ILoggerOptions {
-  prefix?: string,
-  logLevel?: SplitIO.LogLevel,
-  showLevel?: boolean, // @TODO remove this param eventually since it is not being set `false` anymore
+  prefix?: string;
+  logLevel?: SplitIO.LogLevel;
+  showLevel?: boolean; // @TODO remove this param eventually since it is not being set `false` anymore
+  logger?: (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void;
 }
 
 export interface ILogger extends SplitIO.ILogger {
+  setLogger(logger: (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void): void;
+
   debug(msg: any): void;
   debug(msg: string | number, args?: any[]): void;
 

src/utils/settingsValidation/logger/builtinLogger.ts

@@ -40,12 +40,13 @@ if (/^(enabled?|on)/i.test(initialState)) {
  * @param settings - user config object, with an optional `debug` property of type boolean or string log level.
  * @returns a logger instance with the log level at `settings.debug`. If `settings.debug` is invalid or not provided, `initialLogLevel` is used.
  */
-export function validateLogger(settings: { debug: unknown }): ILogger {
-  const { debug } = settings;
+export function validateLogger(settings: { debug: unknown, logger?: unknown }): ILogger {
+  const { debug, logger } = settings;
 
   const logLevel: SplitIO.LogLevel | undefined = debug !== undefined ? getLogLevel(debug) : initialLogLevel;
 
   const log = new Logger({ logLevel: logLevel || initialLogLevel }, allCodes);
+  if (typeof logger === 'function') log.setLogger(logger as (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void);
 
   // @ts-ignore // if logLevel is undefined at this point, it means that settings `debug` value is invalid
   if (!logLevel) log._log(LogLevels.ERROR, 'Invalid Log Level - No changes to the logs will be applied.');

src/utils/settingsValidation/logger/commons.ts

@@ -10,15 +10,11 @@ import SplitIO from '../../../../types/splitio';
  * @returns LogLevel of the given debugValue or undefined if the provided value is invalid
  */
 export function getLogLevel(debugValue: unknown): SplitIO.LogLevel | undefined {
-  if (typeof debugValue === 'boolean') {
-    if (debugValue) {
-      return LogLevels.DEBUG;
-    } else {
-      return LogLevels.NONE;
-    }
-  } else if (typeof debugValue === 'string' && isLogLevelString(debugValue)) {
-    return debugValue;
-  } else {
-    return undefined;
-  }
+  return typeof debugValue === 'boolean' ?
+    debugValue ?
+      LogLevels.DEBUG :
+      LogLevels.NONE :
+    typeof debugValue === 'string' && isLogLevelString(debugValue) ?
+      debugValue :
+      undefined;
 }

src/utils/settingsValidation/logger/pluggableLogger.ts

@@ -17,16 +17,20 @@ let initialLogLevel = LogLevels.NONE;
  * @returns a logger instance, that might be: the provided logger at `settings.debug`, or one with the given `debug` log level,
  * or one with NONE log level if `debug` is not defined or invalid.
  */
-export function validateLogger(settings: { debug: unknown }): ILogger {
-  const { debug } = settings;
+export function validateLogger(settings: { debug: unknown, logger?: unknown }): ILogger {
+  const { debug, logger } = settings;
   let logLevel: SplitIO.LogLevel | undefined = initialLogLevel;
 
   if (debug !== undefined) {
-    if (isLogger(debug)) return debug;
+    if (isLogger(debug)) {
+      if (typeof logger === 'function') debug.setLogger(logger as (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void);
+      return debug;
+    }
     logLevel = getLogLevel(settings.debug);
   }
 
   const log = new Logger({ logLevel: logLevel || initialLogLevel });
+  if (typeof logger === 'function') log.setLogger(logger as (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void);
 
   // @ts-ignore // `debug` value is invalid if logLevel is undefined at this point
   if (!logLevel) log._log(LogLevels.ERROR, 'Invalid `debug` value at config. Logs will be disabled.');

types/splitio.d.ts

@@ -87,6 +87,7 @@ interface ISharedSettings {
    * Do not change these settings unless you're working an advanced use case, like connecting to the Split proxy.
    */
   urls?: SplitIO.UrlSettings;
+  logger?: (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void;
 }
 /**
  * Common settings properties for SDKs with synchronous API (standalone and localhost modes).
@@ -559,6 +560,7 @@ declare namespace SplitIO {
       telemetry: string;
     };
     readonly integrations?: IntegrationFactory[];
+    readonly logger?: (formattedMsg: string, level: SplitIO.LogLevel, msg: string) => void;
     readonly debug: boolean | LogLevel | ILogger;
     readonly version: string;
     /**