wazuh-kibana-app/server/logger.js

const winston = require('winston');
const fs      = require('fs');
const path    = require('path');
let allowed   = false;
/** 
 * Checks if ../../wazuh-logs exists. If it doesn't exist, it will be created.
 */
const initDirectory = () => {
    try{
        if(!path.join(__dirname).includes('/usr/share/kibana') &&
            path.join(__dirname).includes('plugins') && 
            path.join(__dirname).includes('kibana')){

            throw new Error('Kibana is out of /usr/share/kibana path and the Wazuh App is inside plugins directory')
            
        }
        if (!fs.existsSync(path.join(__dirname, '../../wazuh-logs'))) {
            fs.mkdirSync(path.join(__dirname, '../../wazuh-logs'));
        }
        allowed = true;
        return;
    } catch (error) {
        allowed = false;
        console.error(`Cannot create the logs directory due to:\n${error.message || error}`);
    }
}

/** 
 * Here we create the logger
 */
const wazuhlogger = winston.createLogger({
    level     : 'info',
    format    : winston.format.json(),
    transports: [
        new winston.transports.File({ 
            filename: path.join(__dirname, '../../wazuh-logs/wazuhapp.log') 
        })
    ]
});

/**
 * Prevents from exit on error related to the logger.
 */
wazuhlogger.exitOnError = false;

/**
 * Returns given file size in MB, if the file doesn't exist returns 0
 * @param {*} filename Path to the file
 */
const getFilesizeInMegaBytes = filename => {
    if(allowed){
        if (fs.existsSync(filename)) {
            const stats               = fs.statSync(filename)
            const fileSizeInMegaBytes = stats.size

            return fileSizeInMegaBytes / 1000000.0;
        }
    }
    return 0;
}

/** 
 * Checks if the wazuhapp.log file size is greater than 100MB, if so it rotates the file.
 */
const checkFiles = () => {
    if(allowed){
        if (getFilesizeInMegaBytes(path.join(__dirname, '../../wazuh-logs/wazuhapp.log')) >= 100) {
            fs.renameSync(
                path.join(__dirname, '../../wazuh-logs/wazuhapp.log'), 
                path.join(__dirname, `../../wazuh-logs/wazuhapp.${new Date().getTime()}.log`)
            )
        }
    }
};

/**
 * Main function to add a new log
 * @param {*} location File where the log is being thrown
 * @param {*} message Message to show
 * @param {*} level Optional, default is 'error'
 */
const log = (location, message, level) => {
    initDirectory();
    if(allowed){
        checkFiles();
        wazuhlogger.log({
            date    : new Date(),
            level   : level || 'error',
            location: location || 'unknown',
            message : message || 'An error occurred'
        });
    }
};

module.exports = { log }