How to use with Koa?

I see the example is for express.js but I would like to use it with Koa, basically we just want to monitor open file descriptors (it will be hosted on linux) using prometheus.

The docs say:

See example folder for a sample usage. The library does not bundle any web framework, to expose the metrics just return the metrics() function in the registry.

Which I find confusing especially combined with the example which has a globalRegistry on line #5

[SimenB]

The example could probably be better and not use the internal prom-client globalRegistry property.

b4e9be54dc5d1172c78591d095495857c441b7b5

[montanaflynn]

@siimon and @SimenB thanks so much I got it working!

let app = require('koa')();
let router = require('koa-router')();

const { register, collectDefaultMetrics } = require('prom-client');

collectDefaultMetrics();

router.get('/', function *(next) {
    yield next;
    this.body = "hello world";
});

router.get('/metrics', function *(next) {
    yield next;
    this.body = register.metrics();
});

app.use(router.routes());
app.use(router.allowedMethods());

app.listen(3000);
console.log('listening on port 3000');