index.js

'use strict';

const request = require("request");

// This is the function that generates an appender function
function stdoutAppender(layout, levels, config) {

    var silentLevel = levels.getLevel(config.silentAlertLevel);
    var audioLevel = levels.getLevel(config.audioAlertLevel);

    var botchat_params = {
        method: "GET",
        uri: "https://api.telegram.org/bot"+config.bottoken+"/sendMessage",
        qs: {
            chat_id: config.botchatid,
            parse_mode: "html"
        }
    };
    // This is the appender function itself
    const appender = (loggingEvent) => {
        var params = JSON.parse(JSON.stringify(botchat_params));
        if (silentLevel.isLessThanOrEqualTo(loggingEvent.level.levelStr)) {
            //console.log(`===== silentAlertLevel is less than loggingEvent level.`);
            if (audioLevel.isLessThanOrEqualTo(loggingEvent.level.levelStr)) {
                //console.log(`===== log telegram with sound`);
                Object.assign(params.qs, {
                    text: layout(loggingEvent),
                    disable_notification: false
                });
                request(params, (error, response, body) => {
                    if (error) {
                        console.log("Error sending to telegram:");
                        console.log(error);
                    } /* else {
                        console.log("Message sent to telegram:");
                        console.log(body);
                    }*/
                });
            } else {
                //console.log(`===== log telegram quietly`);
                Object.assign(params.qs, {
                    text: layout(loggingEvent),
                    disable_notification: true
                });
                request(params, (error, response, body) => {
                    if (error) {
                        console.log("Error sending to telegram:");
                        console.log(error);
                    } /* else {
                        console.log("Message sent to telegram:");
                        console.log(body);
                    } */
                });
            }
        } /* else {
            console.log(`===== silentAlertLevel is greater than or equal to loggingEvent level.\n===== don't log telegram`);
        } */

        //process.stdout.write(`test: ${layout(loggingEvent)}\n`);
    };

    // add a shutdown function.
    /*
    appender.shutdown = (done) => {
        process.stdout.write('appender shutdown', done);
    };
    */

    return appender;
}

function configure(config, layouts, findAppender, levels) {

    // the default custom layout for this appender, not using the layouts module
    var default_layout = function(loggingEvent) {
        var header = `<b>${loggingEvent.categoryName}: ${loggingEvent.level}</b>\n`;
        var timestamp = `[${loggingEvent.startTime.toISOString()}]\n`;
        var body = loggingEvent.data.map(d => { return d.toString(); }).join("\n");
        return header+timestamp+body;
    }

    var use_layout = config.layout ? layouts.layout(config.layout.type, config.layout) : default_layout;

    //create a new appender instance
    return stdoutAppender(use_layout, levels, config);
}

//export the only function needed
exports.configure = configure;