express prometheus bundle

express middleware with popular prometheus metrics in one bundle.

Internally it uses prom-client. See: https://github.com/siimon/prom-client

Included metrics:

• up: normally is just 1
• nodejs_memory_heap_total_bytes and nodejs_memory_heap_used_bytes
• http_request_seconds: http latency histogram labeled with status_code

Install

npm install express-prom-bundle

Usage

You MUST call app.use(metricsMiddleware) before the use-ing your middleware, otherwise those won't count in http_request_seconds histogram

const promBundle = require("express-prom-bundle"),
const metricsMiddleware = promBundle({/* options */ });

app.use(metricsMiddleware);
app.use(/* your middleware */);
app.listen(3000);

• call your endpoints
• see your metrics here: http://localhost:3000/metrics

Options

• prefix: prefix added to every metric name
• whitelist, blacklist: array of strings or regexp specifying which metrics to include/exclude
• buckets: buckets used for http_request_seconds histogram

Example

setup std. metrics but exclude up-metric:

"use strict";

const express = require("express"),
    app = express(),
    promBundle = require("express-prom-bundle");

app.use(promBundle({
    prefix: "demo_app:something"
}));

app.get("/hello", (req, res) => res.send("ok"));

app.listen(3000);

See an advanced example on github

License

MIT