@balena/node-metrics-gatherer/test/api-collector.spec.ts

// TODO
import * as chai from 'chai';
import { expect } from 'chai';
import chaiHttp = require('chai-http');
import 'mocha';

import * as bodyParser from 'body-parser';
import * as express from 'express';

import { metrics } from '../src';

chai.use(chaiHttp);

describe('API metrics', () => {
	const app = metrics.collectAPIMetrics(express());
	app
		.use(bodyParser.json())
		.post('/echo', (req: express.Request, res: express.Response) => {
			res.send(req.body);
		});
	const server = app.listen(process.env.PORT || 3001);

	const requester = chai.request(app).keepOpen();

	beforeEach(() => {
		metrics.reset();
	});

	after(() => {
		metrics.clear();
		server.close();
	});

	it('should report all metrics after 1 request', done => {
		requester
			.post('/echo')
			.type('json')
			.send({ hello: 'world' })
			.end((err, res) => {
				expect(err).to.be.null;
				expect(res).to.have.status(200);
				const output = metrics.output();
				const metricsRegexps = [
					/api_arrival_total{state="completed",statusCode="200"} 1/,
					/api_bytes_read_bucket{le="\+Inf",state="completed",statusCode="200"} 1/,
					/api_bytes_written_bucket{le="\+Inf",state="completed",statusCode="200"} 1/,
					/api_latency_seconds_count{state="completed",statusCode="200"} 1/,
				];
				metricsRegexps.forEach(re => {
					expect(re.test(output)).to.be.true;
				});
				done();
			});
	});
});