Add logging framework with Logger, LoggerFactory, and appenders

- Introduced ILogger interface for logging methods
- Implemented Logger class with various logging levels and message formatting
- Created LoggerFactory for managing logger instances and appender configuration
- Added LoggingLevel enum and mapping for logging level types
- Developed ConsoleAppender and TechnikerMeAppender for different logging outputs
- Implemented appender management with AppenderFactory and base Appender class
- Established Threshold class for controlling logging levels

src/logger/ILogger.ts

@@ -0,0 +1,7 @@
+export interface ILogger {
+    info(message: string, ...optionalParams: unknown[]): void;
+    debug(message: string, ...optionalParams: unknown[]): void;
+    warn(message: string, ...optionalParams: unknown[]): void;
+    error(message: string, ...optionalParams: unknown[]): void;
+    trace(message: string, ...optionalParams: unknown[]): void;
+}

src/logger/Logger.ts

@@ -0,0 +1,102 @@
+import type { ILogger } from './ILogger';
+import { LoggingLevel } from './LoggingLevel';
+import type { Threshold } from './Threshold';
+import type { IAppender } from './appenders/IAppender';
+import LoggingLevelMapping from './LoggingLevelMapping';
+
+export default class Logger implements ILogger {
+  private readonly _category: string;
+  private readonly _threshold: Threshold;
+  private readonly _appenders: Set<IAppender>;
+  constructor(category: string, threshold: Threshold, appenders: Set<IAppender>) {
+    this._category = category;
+    this._threshold = threshold;
+    this._appenders = appenders;
+  }
+
+  public info(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Info) {
+      return;
+    }
+
+    this.log(LoggingLevel.Info, message, ...optionalParameters);
+  }
+
+  public warn(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Warn) {
+      return;
+    }
+
+    this.log(LoggingLevel.Warn, message, ...optionalParameters);
+  }
+
+  public error(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Error) {
+      return;
+    }
+
+    this.log(LoggingLevel.Error, message, ...optionalParameters);
+  }
+
+  public debug(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Debug) {
+      return;
+    }
+
+    this.log(LoggingLevel.Debug, message, ...optionalParameters);
+  }
+
+  public trace(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Trace) {
+      return;
+    }
+
+    this.log(LoggingLevel.Trace, message, ...optionalParameters);
+  }
+
+  public silly(message: string, ...optionalParameters: unknown[]): void {
+    if (this._threshold.value > LoggingLevel.Silly) {
+      return;
+    }
+
+    this.log(LoggingLevel.Silly, message, ...optionalParameters);
+  }
+
+  private formatMessage(message: string, ...optionalParameters: unknown[]): string {
+    let optionalParameterIndex = 0;
+
+    return message.replace(/%[sdj]/g, match => {
+      if (optionalParameterIndex >= optionalParameters.length) {
+        return match;
+      }
+
+      const param = optionalParameters[optionalParameterIndex++];
+
+      switch (match) {
+        case '%s':
+          return String(param);
+        case '%d':
+          return typeof param === 'number' ? param.toString() : 'NaN';
+        case '%j':
+          try {
+            return JSON.stringify(param);
+          } catch {
+            return '[Circular]';
+          }
+
+        default:
+          return match;
+      }
+    });
+  }
+
+  private log(loggingLevel: LoggingLevel, message: string, ...optionalParameters: unknown[]): void {
+    const timestamp = new Date().toISOString();
+    const formattedMessage = this.formatMessage(message, ...optionalParameters);
+    const level = LoggingLevelMapping.convertLoggingLevelToLoggingLevelType(loggingLevel);
+
+    for (const appender of this._appenders) {
+      appender.log(timestamp, level, this._category, formattedMessage);
+    }
+  }
+}

src/logger/LoggerFactory.ts

@@ -0,0 +1,43 @@
+import type { IAppender } from "./appenders/IAppender";
+import Logger from './Logger';
+import type { LoggingLevelType } from "./LoggingLevel";
+import LoggingLevelMapping from "./LoggingLevelMapping";
+import { Threshold } from "./Threshold";
+import ConsoleAppender from "./appenders/ConsoleAppender";
+import Disposable from "../lang/disposables/Disposable";
+
+type Category = string;
+
+export default class LoggerFactory {
+  private static readonly _appenders: Set<IAppender> = new Set();
+  private static readonly _threshold: Threshold = new Threshold();
+  private static readonly _loggers: Map<Category, Logger> = new Map();
+
+  static {
+    this.applyConsoleAppender();
+  }
+
+  public static getLogger(category: string): Logger {
+    if (!LoggerFactory._loggers.has(category)) {
+      this._loggers.set(category, new Logger(category, LoggerFactory._threshold, LoggerFactory._appenders));
+    }
+
+    return LoggerFactory._loggers.get(category) as Logger;
+  }
+
+  public static applyAppender(appender: IAppender): Disposable {
+    LoggerFactory._appenders.add(appender);
+
+    return new Disposable(() => LoggerFactory._appenders.delete(appender));
+  }
+
+  public static setLoggingLevel(loggingLevelType: LoggingLevelType): void {
+    const loggingLevel = LoggingLevelMapping.convertLoggingLevelTypeToLoggingLevel(loggingLevelType);
+
+    LoggerFactory._threshold.value = loggingLevel;
+  }
+
+  private static applyConsoleAppender(): void {
+    LoggerFactory.applyAppender(new ConsoleAppender());
+  }
+}

src/logger/LoggingLevel.ts

@@ -0,0 +1,12 @@
+export enum LoggingLevel {
+  Off = -1,
+  Debug = 10,
+  Trace = 20,
+  Silly = 30,
+  Info = 40,
+  Warn = 50,
+  Error = 60,
+  All = 70
+}
+
+export type LoggingLevelType = 'Off' | 'Debug' | 'Trace' | 'Info' | 'Silly' | 'Warn' | 'Error' | 'All';

src/logger/LoggingLevelMapping.ts

@@ -0,0 +1,52 @@
+
+import {assertUnreachable} from '@techniker-me/tools';
+import {LoggingLevel, type LoggingLevelType} from './LoggingLevel';
+
+export default class LoggingLevelMapping {
+  public static convertLoggingLevelToLoggingLevelType(loggingLevel: LoggingLevel): LoggingLevelType {
+    switch (loggingLevel) {
+      case LoggingLevel.Off:
+        return 'Off';
+      case LoggingLevel.Info:
+        return 'Info';
+      case LoggingLevel.Warn:
+        return 'Warn';
+      case LoggingLevel.Error:
+        return 'Error';
+      case LoggingLevel.Debug:
+        return 'Debug';
+      case LoggingLevel.Trace:
+        return 'Trace';
+      case LoggingLevel.Silly:
+        return 'Silly';
+      case LoggingLevel.All:
+        return 'All';
+
+      default:
+        assertUnreachable(loggingLevel);
+    }
+  }
+
+  public static convertLoggingLevelTypeToLoggingLevel(loggingLevelType: LoggingLevelType): LoggingLevel {
+    switch (loggingLevelType) {
+      case 'Off':
+        return LoggingLevel.Off;
+      case 'Info':
+        return LoggingLevel.Info;
+      case 'Warn':
+        return LoggingLevel.Warn;
+      case 'Error':
+        return LoggingLevel.Error;
+      case 'Debug':
+        return LoggingLevel.Debug;
+      case 'Trace':
+        return LoggingLevel.Trace;
+      case 'Silly':
+        return LoggingLevel.Silly;
+      case 'All':
+        return LoggingLevel.All;
+      default:
+        assertUnreachable(loggingLevelType);
+    }
+  }
+}

src/logger/Threshold.ts

@@ -0,0 +1,19 @@
+import Defaults from '../Defaults';
+import { Subject } from '../lang/observables';
+import { LoggingLevel } from './LoggingLevel';
+
+export class Threshold {
+  private _threshold: Subject<LoggingLevel>;
+
+  constructor(loggingLevel?: LoggingLevel) {
+    this._threshold = new Subject(loggingLevel ?? Defaults.loggingLevel);
+  }
+
+  set value(value: LoggingLevel) {
+    this._threshold.value = value;
+  }
+
+  get value(): LoggingLevel {
+    return this._threshold.value;
+  }
+}

src/logger/appenders/Appender.ts

@@ -0,0 +1,63 @@
+import {LoggingLevel, type LoggingLevelType} from '../LoggingLevel';
+import type ILogMessage from './LogMessage';
+
+export type AppenderOptions = {
+  domain?: string;
+};
+
+export default class Appender {
+  private readonly _logRecorderUrl: string = 'https://logserver.techniker.me/api/logs';
+  // @ts-ignore
+  private readonly _domain: string = typeof globalThis !== 'undefined' ? (globalThis.location?.hostname ?? '') : '';
+  private readonly _logMessageQueue: ILogMessage[] = [];
+  private _pendingPostLogMessagePromise: Promise<Response | undefined> | undefined = undefined;
+
+  constructor(logRecorderUrl: string, {domain}: AppenderOptions) {
+    this._logRecorderUrl = logRecorderUrl;
+    this._domain = domain ?? this._domain;
+  }
+
+  public log(timestamp: string, level: LoggingLevelType, category: string, message: string): void {
+    const logMessage = {
+      timestamp,
+      domain: this._domain,
+      level,
+      category,
+      message
+    };
+    this.queueMessage(logMessage);
+    this.postLogMessage();
+  }
+
+  private async postLogMessage(): Promise<void> {
+    const logMessage = this._logMessageQueue.shift();
+
+    if (!logMessage || this._pendingPostLogMessagePromise !== undefined) {
+      return;
+    }
+
+    try {
+      if (typeof fetch === 'undefined') {
+        console.error('Fetch API is not available in this environment');
+        return;
+      }
+
+      this._pendingPostLogMessagePromise = fetch(this._logRecorderUrl, {
+        headers: {
+          'Content-Type': 'application/json',
+          Accept: 'application/json'
+        },
+        mode: 'no-cors',
+        method: 'POST',
+        body: JSON.stringify(logMessage)
+      }).then(() => (this._pendingPostLogMessagePromise = undefined));
+    } catch (e) {
+      console.error('Unable to send logs due to [%o]', e);
+      return;
+    }
+  }
+
+  private queueMessage(logMessage: ILogMessage): void {
+    this._logMessageQueue.push(logMessage);
+  }
+}

src/logger/appenders/AppenderFactory.ts

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+import Appender from './Appender';
+import type { AppenderOptions } from './Appender';
+
+export default class AppnederFactory {
+  public static createRemoteAppender(remoteAppenderUrl: string, {domain}: AppenderOptions): Appender {
+    return new Appender(remoteAppenderUrl, {domain: domain ?? ''});
+  }
+
+  private constructor() {
+    throw new Error('AppenderFactory is a static class that may not be instantiated');
+  }
+}

src/logger/appenders/ConsoleAppender.ts

@@ -0,0 +1,31 @@
+import {LoggingLevel, type LoggingLevelType} from '../LoggingLevel';
+import LoggingLevelMapping from '../LoggingLevelMapping';
+import type {IAppender} from './IAppender';
+import {assertUnreachable} from '@techniker-me/tools';
+
+export default class ConsoleAppender implements IAppender {
+  public log(timestamp: string, level: LoggingLevelType, category: string, message: string) {
+    const loggingLevel = LoggingLevelMapping.convertLoggingLevelTypeToLoggingLevel(level);
+
+    switch (loggingLevel) {
+      case LoggingLevel.Off:
+        break;
+
+      case LoggingLevel.Warn:
+      case LoggingLevel.Error:
+        console.error(`${timestamp} [${level}] [${category}] ${message}`);
+        break;
+
+      case LoggingLevel.Info:
+      case LoggingLevel.Debug:
+      case LoggingLevel.Trace:
+      case LoggingLevel.Silly:
+      case LoggingLevel.All:
+        console.log(`${timestamp} [${level}] [${category}] ${message}`);
+        break;
+
+      default:
+        assertUnreachable(loggingLevel);
+    }
+  }
+}

src/logger/appenders/IAppender.ts

@@ -0,0 +1,5 @@
+import type { LoggingLevelType } from '../LoggingLevel';
+
+export interface IAppender {
+  log(timestamp: string, level: LoggingLevelType, category: string, message: string): void;
+}

src/logger/appenders/LogMessage.ts

@@ -0,0 +1,6 @@
+export default interface ILogMessage {
+  timestamp: string;
+  level: string;
+  category: string;
+  message: string;
+}

src/logger/appenders/TechnikerMeAppender.ts

@@ -0,0 +1,55 @@
+import type {LoggingLevel, LoggingLevelType} from '../LoggingLevel';
+import type {IAppender} from './IAppender';
+import type ILogMessage from './LogMessage';
+
+export default class TechnikerMeAppender implements IAppender {
+  private readonly _logRecorderUrl: string = 'https://logserver.techniker.me/api/logs';
+  // @ts-ignore
+  private readonly _domain: string = typeof globalThis !== 'undefined' ? (globalThis.location?.hostname ?? '') : '';
+  private readonly _logMessageQueue: ILogMessage[] = [];
+  private _pendingPostLogMessagePromise: Promise<Response | undefined> | undefined = undefined;
+
+  public log(timestamp: string, level: LoggingLevelType, category: string, message: string): void {
+    const logMessage = {
+      timestamp,
+      domain: this._domain,
+      level,
+      category,
+      message
+    };
+    this.queueMessage(logMessage);
+    this.postLogMessage();
+  }
+
+  private async postLogMessage(): Promise<void> {
+    const logMessage = this._logMessageQueue.shift();
+
+    if (!logMessage || this._pendingPostLogMessagePromise !== undefined) {
+      return;
+    }
+
+    try {
+      if (typeof fetch === 'undefined') {
+        console.error('Fetch API is not available in this environment');
+        return;
+      }
+
+      this._pendingPostLogMessagePromise = fetch(this._logRecorderUrl, {
+        headers: {
+          'Content-Type': 'application/json',
+          Accept: 'application/json'
+        },
+        mode: 'no-cors',
+        method: 'POST',
+        body: JSON.stringify(logMessage)
+      }).then(() => (this._pendingPostLogMessagePromise = undefined));
+    } catch (e) {
+      console.error('Unable to send logs due to [%o]', e);
+      return;
+    }
+  }
+
+  private queueMessage(logMessage: ILogMessage): void {
+    this._logMessageQueue.push(logMessage);
+  }
+}