blinky/libs/logger.js

// requirements
const config = require("../config.json");
// third party requirements
const moment = require("moment");

// constants
const LOG_PREFIX_DEBUG = "debug";
const LOG_PREFIX_INFO = "info";
const LOG_PREFIX_WARNING = "warning";
const LOG_PREFIX_ERROR = "error";
const LOGLEVEL_DEBUG = 0;
const LOGLEVEL_INFO = 1;
const LOGLEVEL_WARNING = 2;
const LOGLEVEL_ERROR = 3;

// set loglevel on "require"
const loglevel = function() {
    switch (config.log.level) {
        case LOG_PREFIX_DEBUG:
        case LOGLEVEL_DEBUG:
            return LOGLEVEL_DEBUG;
        case LOG_PREFIX_INFO:
        case LOGLEVEL_INFO:
            return LOGLEVEL_INFO;
        case LOG_PREFIX_WARNING:
        case LOGLEVEL_WARNING:
            return LOGLEVEL_WARNING;
        case LOG_PREFIX_ERROR:
        case LOGLEVEL_ERROR:
            return LOGLEVEL_ERROR;
        default:
            return LOGLEVEL_INFO;
    }
}();

// log a http request
function logRequest(request) {
    let message = "[" + request.method + "] url: \"" + request.url + "\"";
    let counter = 1;
    for (let param in request.body) {
        message += ", parameter " + counter + ": \"" + param + "=" + request.body[param] + "\"";
        counter++;
    }
    debug(message.trim());
}

// prefix log with "info"
function info(message) {
    if (loglevel > LOGLEVEL_INFO) {
        return;
    }
    trace(message);
}

// prefix log with "info"
function warn(message) {
    if (loglevel > LOGLEVEL_WARNING) {
        return;
    }
    trace(message, "warning");
}

// prefix log with "debug"
function debug(message) {
    if (loglevel > LOGLEVEL_DEBUG) {
        return;
    }
    trace(message, "debug");
}

// prefix log with "error"
function error(message) {
    if (loglevel > LOGLEVEL_ERROR) {
        return;
    }
    trace(message, "error");
}

// default logging function
function trace(message, prefix) {
    if (message === undefined || message === null || message.length === 0) {
        return;
    }
    if (prefix === undefined || prefix === null || prefix.length === 0) {
        prefix = "info";
    }
    let print;
    switch (prefix) {
        case "error":
            print = console.error;
            break;
        case "debug":
            print = console.debug;
            break;
        case "warning":
            print = console.warn;
            break;
        default:
            print = console.log;
    }
    message = moment().format(config.server.timestamp) + " | " + prefix + " > " + message;
    print(message);
}

// exports
module.exports = {
    info,
    warn,
    debug,
    error,
    logRequest
};