Initial 1.0.0 commit (library extracted from existing project).

src/api-log-appender.ts

@@ -0,0 +1,83 @@
+import Axios from 'axios';
+
+import { LogMessage, LogLevel } from './log-message';
+import LogAppender from './log-appender';
+
+interface ApiMessage {
+  level: string;
+  message: string;
+  scope: string;
+  stacktrace: string;
+  timestamp: string;
+}
+export class ApiLogAppender implements LogAppender {
+  public batchSize = 10;
+  public minimumTimePassedInSec = 60;
+  public maximumTimePassedInSec = 120;
+  public threshold = LogLevel.ALL;
+
+  private http = Axios.create();
+  private msgBuffer: ApiMessage[] = [];
+  private lastSent = 0;
+
+  constructor(
+    public readonly apiEndpoint: string,
+    public authToken?: string,
+    threshold?: LogLevel
+  ) {
+    setTimeout(this.checkPost, 1000);
+    if (threshold) {
+      this.threshold = threshold;
+    }
+  }
+
+  public appendMessage(msg: LogMessage): void {
+    if (this.threshold && msg.level < this.threshold) {
+      return;
+    }
+
+    this.msgBuffer.push({
+      level: LogLevel[msg.level],
+      message:
+        typeof msg.message === 'string'
+          ? msg.message
+          : JSON.stringify(msg.message),
+      scope: msg.scope,
+      stacktrace: msg.stacktrace,
+      timestamp: msg.timestamp.toISOString()
+    });
+  }
+
+  private doPost() {
+    if (this.msgBuffer.length > 0 && this.authToken) {
+      this.http.post(this.apiEndpoint, this.msgBuffer, {
+        headers: {
+          'Content-Type': 'application/json',
+          Authorization: `Bearer ${this.authToken}`
+        }
+      });
+
+      this.lastSent = Date.now();
+      this.msgBuffer = [];
+    }
+  }
+
+  private checkPost = () => {
+    const now = Date.now();
+    const min = this.lastSent + this.minimumTimePassedInSec * 1000;
+    const max = this.lastSent + this.maximumTimePassedInSec * 1000;
+
+    if (
+      (this.msgBuffer.length >= this.batchSize && min < now) ||
+      (this.msgBuffer.length > 0 && max < now)
+    ) {
+      this.doPost();
+    }
+    setTimeout(
+      this.checkPost,
+      Math.max(10000, this.minimumTimePassedInSec * 1000)
+    );
+  };
+}
+
+export default ApiLogAppender;

src/console-log-appender.ts

@@ -0,0 +1,55 @@
+/*tslint:disable:no-console*/
+import { LogMessage, LogLevel } from './log-message';
+import LogAppender from './log-appender';
+
+export class ConsoleLogAppender implements LogAppender {
+  public threshold = LogLevel.ALL;
+
+  constructor(threshold?: LogLevel) {
+    if (threshold) {
+      this.threshold = threshold;
+    }
+  }
+
+  public appendMessage(msg: LogMessage): void {
+    if (this.threshold && msg.level < this.threshold) {
+      return;
+    }
+
+    let logMethod = console.log;
+    switch (msg.level) {
+      case LogLevel.ALL:
+        logMethod = console.log;
+        break;
+      case LogLevel.TRACE:
+        logMethod = console.log;
+        break;
+      case LogLevel.DEBUG:
+        logMethod = console.debug;
+        break;
+      case LogLevel.LOG:
+        logMethod = console.log;
+        break;
+      case LogLevel.INFO:
+        logMethod = console.info;
+        break;
+      case LogLevel.WARN:
+        logMethod = console.warn;
+        break;
+      case LogLevel.ERROR:
+      case LogLevel.FATAL:
+        logMethod = console.trace;
+        break;
+    }
+
+    if (msg.error) {
+      logMethod(`[${msg.scope}]:`, msg.message, msg.error);
+    } else if (msg.stacktrace) {
+      logMethod(`[${msg.scope}]:`, msg.message, msg.stacktrace);
+    } else {
+      logMethod(`[${msg.scope}]:`, msg.message);
+    }
+  }
+}
+
+export default ConsoleLogAppender;

src/index.ts

@@ -0,0 +1,6 @@
+export * from './log-message';
+export * from './log-appender';
+export * from './log-service';
+export * from './console-log-appender';
+export * from './api-log-appender';
+export * from './logger';

src/log-appender.ts

@@ -0,0 +1,5 @@
+import { LogLevel, LogMessage } from './log-message';
+export default interface LogAppender {
+  threshold: LogLevel;
+  appendMessage(message: LogMessage): void;
+}

src/log-message.ts

@@ -0,0 +1,21 @@
+export enum LogLevel {
+  ALL = 0,
+  TRACE,
+  DEBUG,
+  LOG,
+  INFO,
+  WARN,
+  ERROR,
+  FATAL
+}
+
+export interface LogMessage {
+  scope: string;
+  level: LogLevel;
+  message: string | object;
+  stacktrace: string;
+  error?: Error;
+  timestamp: Date;
+}
+
+export default LogMessage;

src/log-service.ts

@@ -0,0 +1,48 @@
+import { LogLevel } from './log-message';
+import Logger from './logger';
+
+const ROOT_LOGGER_NAME = 'ROOT';
+
+export class LogService {
+  private loggers: { [key: string]: Logger };
+
+  public get ROOT_LOGGER() {
+    return this.loggers[ROOT_LOGGER_NAME];
+  }
+
+  public constructor() {
+    this.loggers = {};
+    this.loggers[ROOT_LOGGER_NAME] = new Logger(
+      ROOT_LOGGER_NAME,
+      undefined,
+      LogLevel.ALL
+    );
+  }
+
+  public getLogger(name: string, threshold?: LogLevel): Logger {
+    if (this.loggers[name]) {
+      return this.loggers[name];
+    }
+
+    let parentLogger: Logger;
+
+    const parentLoggerName = Object.keys(this.loggers)
+      .filter((n: string) => name.startsWith(n))
+      .reduce(
+        (acc: string, cur: string) => (acc.length > cur.length ? acc : cur),
+        ''
+      );
+
+    if (parentLoggerName) {
+      parentLogger = this.loggers[parentLoggerName];
+    } else {
+      parentLogger = this.ROOT_LOGGER;
+    }
+
+    this.loggers[name] = parentLogger.createChildLogger(name, threshold);
+    return this.loggers[name];
+  }
+}
+
+export const logService = new LogService();
+export default logService;

src/logger.ts

@@ -0,0 +1,108 @@
+import { LogMessage, LogLevel } from './log-message';
+import LogAppender from './log-appender';
+
+export type DeferredMsg = () => string | object;
+export type MessageType = string | DeferredMsg | object;
+
+export class Logger {
+  public appenders: LogAppender[] = [];
+
+  public constructor(
+    public readonly name: string,
+    private parentLogger?: Logger,
+    public threshold?: LogLevel
+  ) {}
+
+  public createChildLogger(name: string, threshold?: LogLevel): Logger {
+    return new Logger(name, this, threshold);
+  }
+
+  public doLog(
+    level: LogLevel,
+    message: Error | MessageType,
+    stacktrace?: string
+  ): void {
+    if (level < this.getEffectiveThreshold()) {
+      return;
+    }
+
+    const logMsg: LogMessage = {
+      scope: this.name,
+      level,
+      message: '',
+      stacktrace: '',
+      timestamp: new Date()
+    };
+
+    if (message === undefined || message === null) {
+      logMsg.message = message;
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    } else if ((message as DeferredMsg).call !== undefined) {
+      logMsg.message = (message as DeferredMsg)();
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    } else if (message instanceof Error) {
+      const error = message as Error;
+      logMsg.error = error;
+      logMsg.message = `${error.name}: ${error.message}`;
+      logMsg.stacktrace = error.stack == null ? '' : error.stack;
+    } else {
+      // string | object
+      logMsg.message = message;
+      logMsg.stacktrace = stacktrace == null ? '' : stacktrace;
+    }
+
+    this.sendToAppenders(logMsg);
+  }
+
+  public trace(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.TRACE, message, stacktrace);
+  }
+
+  public debug(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.DEBUG, message, stacktrace);
+  }
+
+  public log(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.LOG, message, stacktrace);
+  }
+
+  public info(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.INFO, message, stacktrace);
+  }
+
+  public warn(message: MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.WARN, message, stacktrace);
+  }
+
+  public error(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.ERROR, message, stacktrace);
+  }
+
+  public fatal(message: Error | MessageType, stacktrace?: string): void {
+    this.doLog(LogLevel.FATAL, message, stacktrace);
+  }
+
+  protected sendToAppenders(logMsg: LogMessage) {
+    this.appenders.forEach(app => {
+      app.appendMessage(logMsg);
+    });
+
+    if (this.parentLogger) {
+      this.parentLogger.sendToAppenders(logMsg);
+    }
+  }
+
+  protected getEffectiveThreshold(): LogLevel {
+    if (this.threshold) {
+      return this.threshold;
+    }
+    if (this.parentLogger) {
+      return this.parentLogger.getEffectiveThreshold();
+    }
+
+    // should never happen (root logger should always have a threshold
+    return LogLevel.ALL;
+  }
+}
+
+export default Logger;