@vaibhavkaul69/monitoring-logger/lib/monitoring.js

Reusable monitoring and logging middleware for backend servicses

require("dotenv").config();
const client = require("prom-client");
const responseTime = require("response-time");

client.collectDefaultMetrics();

const reqResTime = new client.Histogram({
  name: "http_request_duration_seconds",
  help: "Duration of HTTP requests in seconds",
  labelNames: ["route", "status_code"],
  buckets: [0.1, 0.5, 1, 1.5, 2, 5],
});

const getOnlyRouteFromRequest = (url) => {
  // Customize this based on your use case
  return url.split("?")[0];
};

const monitoringMiddleware = (app) => {
  app.use(
    responseTime((req, res, time) => {
      const timeInSeconds = time / 1000;
      const route = getOnlyRouteFromRequest(req.originalUrl);
      const statusCode = res.statusCode;
      reqResTime.labels(route, statusCode).observe(timeInSeconds);
    })
  );

  app.get("/metrics", async (req, res) => {
    res.setHeader("Content-Type", client.register.contentType);
    const metrics = await client.register.metrics();
    res.send(metrics);
  });
};

module.exports = monitoringMiddleware;