dg-npm-templates/templates/dg-nodejs-backend-app/src/logger.js

Npx generator for react app dependency creation by digite

const { createLogger, format } = require("winston");
const LokiTransport = require("winston-loki");
const responseTime = require("response-time");

let logger;

const setupLogger = app => {
    const lokiURL = process.env.LOKI_URL;

    if ( lokiURL ) {
        logger = createLogger({
            transports: [
                new LokiTransport({
                    host: lokiURL,
                    labels: {
                        origin: process.env.APP_NAME,
                        application: process.env.APP_NAME
                    },
                    json: true,
                    format: format.json(),
                    replaceTimestamp: true,
                    basicAuth: process.env.LOKI_BASICAUTH
                })
            ]
        });

        app.use(responseTime(logResponseTime));
        app.use(logError);

        console.log("Loki Logger is configured and logs will be pushed to", lokiURL);
    } else {
        console.log("Loki Logger is not configured");
    }
};

const logResponseTime = (req, res, time) => {
    logger.info({
        message: {
            app: req.app_name || process.env.APP_NAME,
            method: req.method,
            host: req.headers.host,
            path: req.originalUrl,
            status: res.statusCode,
            duration: time + "ms",
            "x-fabric-correlation": req.headers["x-fabric-correlation"] || req.headers["X-FABRIC-CORRELATION"] || ""
        },
        labels: {
            application: req.app_name || process.env.APP_NAME
        }
    });
};

const logError = (err, req, res, next) => {
    logger.error({
        message: {
            app: req.app_name || process.env.APP_NAME,
            method: req.method,
            host: req.headers.host,
            path: req.originalUrl,
            status: res.statusCode,
            error: err.stack
        },
        labels: {
            application: req.app_name
        }
    });

    next();
};

module.exports = { 
  setupLogger,
  logError
};