a.js

var apm = require('elastic-apm-node').start()
var http = require('http')
var process = require('process')

function sleep(time) {
    var stop = new Date().getTime();
    while(new Date().getTime() < stop + time) {
        ;
    }
}

function serve(op) {
	if (op == "error") {
		throw new Error("oops, a test error!")
	}

	console.log("sleep", op)
	sleep(parseInt(op))
}

http.createServer(function (req, res) {
	apm.setTransactionName(req.method +' ' + req.url)

	op = req.url.substr(1)
	console.log(op)

	try {
		serve(op)
	} catch (err) {
		apm.captureError(err)
	}

	res.end()
}).listen(3000)