betfair/src/lib/logger.js

Betfair JSON API

// (C) 2016 Anton Zemlyanov, rewritten in JavaScript 6 (ES6)
'use strict';

/*
 * This logger generates bunyan-compatible logs
 * use 'npm install -g bunyan' to install log formatter
 */

let os = require('os');
let fs = require('fs');
let _ = require('lodash');

const LOG_LEVELS = {
    TRACE: 10,
    DEBUG: 20,
    INFO: 30,
    WARN: 40,
    ERROR: 50,
    FATAL: 60
};

class Logger {
    constructor(name, logLevel = 'INFO') {
        this.name = name;
        this.currentLogLevel = LOG_LEVELS[logLevel.toUpperCase()];
        this.logs = [];

        ['trace', 'debug', 'info', 'warn', 'error', 'fatal'].forEach((level) => {
            this[level] = (message, data) => {
                let logLevel = LOG_LEVELS[level.toUpperCase()];
                if (logLevel < this.currentLogLevel) {
                    return;
                }
                const now = new Date();
                let logItem = {
                    name: this.name,
                    hostname: os.hostname(),
                    pid: process.pid,
                    level: logLevel,
                    msg: message,
                    time: now.toISOString(),
                    v: '0'
                };
                if (data) {
                    if(_.isArray(data)) {
                        data = {data: data};
                    }
                    _.extend(logItem, data);
                }
                this.logs.forEach((log) => {log.write(logItem)});
            }
        });
    }

    addFileLog(filename) {
        let log = new FileLog(filename);
        this.logs.push(log);
        return log;
    }

    addMemoryLog(limit) {
        let log = new MemoryLog(limit);
        this.logs.push(log);
        return log;
    }

    close() {
        this.logs.forEach((log) => {
            log.close()
        });
        this.logs = [];
    }
}

class FileLog {
    constructor(filename) {
        this.file = fs.createWriteStream(filename, {flags: 'w', defaultEncoding: 'utf8', autoClose: true});
        this.file.on('error', (error) => {
            console.log('file log error', error);
        });
    }

    write(data) {
        this.file.write(JSON.stringify(data) + '\n');
    }

    close() {
        this.file.end();
    }
}

class MemoryLog {
    constructor(limit = 256) {
        this.limit = limit;
        this.log = [];
    }

    write(data) {
        this.log.push(data);
        while (this.log.length > this.limit) {
            this.log.shift();
        }
    }

    flush() {
    }

    getRecords() {
        return this.log;
    }
}

module.exports = Logger;