cloudron-box/syslog.js

#!/usr/bin/env node

'use strict';

exports = module.exports = {
    start,
    stop
};

const debug = require('debug')('syslog:server'),
    fs = require('fs'),
    net = require('net'),
    path = require('path'),
    paths = require('./src/paths.js'),
    parser = require('nsyslog-parser'),
    util = require('util');

let gServer = null;

async function start() {
    debug('==========================================');
    debug('          Cloudron Syslog Daemon          ');
    debug('==========================================');

    gServer = net.createServer();

    gServer.on('error', function (error) {
        console.error(`server error: ${error}`);
    });

    gServer.on('connection', function (socket) {
        socket.on('data', function (msg) {
            const info = parser(msg.toString());

            if (!info || !info.appName) return debug('Ignore unknown app log:', msg.toString());

            // remove line breaks to avoid holes in the log file
            // we do not ignore empty log lines, to allow gaps for potential ease of readability
            const message = info.message.replace(/\n/g, '');

            const appLogDir = path.join(paths.LOG_DIR, info.appName);

            try {
                fs.mkdirSync(appLogDir, { recursive: true });
                fs.appendFileSync(`${appLogDir}/app.log`, info.ts.toISOString() + ' ' + message + '\n');
            } catch (error) {
                console.error(error);
            }
        });

        socket.on('error', function (error) {
            console.error(`socket error: ${error}`);
        });
    });

    await fs.promises.rm(paths.SYSLOG_SOCKET_FILE, { force: true });
    await util.promisify(gServer.listen.bind(gServer))(paths.SYSLOG_SOCKET_FILE);

    debug(`Listening on ${paths.SYSLOG_SOCKET_FILE}`);
}

async function stop() {
    await fs.promises.rm(paths.SYSLOG_SOCKET_FILE, { force: true });
    gServer.unref(); // TODO : cleanup client connections. otherwise server.close() won't return
    gServer = null;
}

async function main() {
    await start();

    process.on('SIGTERM', async function () {
        debug('Received SIGTERM. Shutting down.');
        await stop();
        setTimeout(process.exit.bind(process), 1000);
    });
}

if (require.main === module) {
    main();
}