git.r.bdr.sh - rbdr/cologne/blob - lib/cologne/logger/file.js

   1 'use strict';
   2
   3 let fs = require('fs');
   4
   5 let LogUtilities = require('../log_utilities');
   6
   7 /**
   8  * Logger for files.
   9  *
  10  * @memberof Cologne.Logger
  11  * @implements Cologne.ILogger
  12  * @class File
  13  */
  14 let FileLogger = class FileLogger {
  15   constructor (config) {
  16
  17     /**
  18      * Path to the file it will write to, must be readable.
  19      *
  20      * @name file
  21      * @instance
  22      * @memberof Cologne.Logger.File
  23      * @type string
  24      * @default null
  25      */
  26     this.file = null;
  27
  28     /**
  29      * The formatter it will use to output the log. If not present it
  30      * will output raw JSON
  31      *
  32      * @name formatter
  33      * @instance
  34      * @memberof Cologne.Logger.File
  35      * @type Cologne.IFormatter
  36      * @default null
  37      */
  38     this.formatter = null;
  39
  40     Object.assign(this, config || {});
  41
  42     this._stream = fs.createWriteStream(this.file, {flags: 'a'});
  43   }
  44
  45   /**
  46    * Main entry point, for each incoming argument it will attempt to
  47    * format and send to the stream to be written.
  48    *
  49    * @function log
  50    * @instance
  51    * @memberof Cologne.Logger.File
  52    * @return {undefined}
  53    */
  54   log () {
  55     let logObject;
  56
  57     for (logObject of arguments) {
  58       this._stream.write(this.format(logObject) + '\n');
  59     }
  60   }
  61
  62   format (logObject) {
  63     if (this.formatter) {
  64       return this.formatter.format(logObject);
  65     }
  66
  67     return LogUtilities.stringify(logObject);
  68   }
  69 };
  70
  71 module.exports = FileLogger;