'GoError: unexpected EOF' when running behind corporate proxy

[lhotrifork]

Hi,

I've just made my first xk6 extension which was very fun! Basically it allows you to talk to NATS from k6 scripts.
Everything is working fine on localhost (as always), however I see an error when running in our staging environment, where every outgoing HTTP request must go through our corporate proxy.

Extension code:

package nats

import (
	"context"

	"time"

	"github.com/loadimpact/k6/js/common"
	"github.com/nats-io/nats.go"

	"github.com/loadimpact/k6/js/modules"
)

func init() {
	modules.Register("k6/x/nats", new(Nats))
}

type Nats struct{}

type Client struct {
	client         *nats.Conn
	defaultTimeout time.Duration
}

func (r *Nats) XClient(ctxPtr *context.Context, natsServer string, timeoutMS int) interface{} {
	rt := common.GetRuntime(*ctxPtr)

	conn, err := nats.Connect(natsServer)
	if err != nil {
		panic(err)
	}
	var timeout time.Duration
	if timeoutMS == 0 {
		timeout = time.Millisecond * 5 // 5 second default timeout
	} else {
		timeout = time.Millisecond * time.Duration(timeoutMS)
	}
	return common.Bind(rt, &Client{client: conn, defaultTimeout: timeout}, ctxPtr)
}

func (c *Client) Request(subject string, payload string) (string, error) {
	msg, err := c.client.Request(subject, []byte(payload), c.defaultTimeout)
	if err != nil {
		return "", err
	}
	return string(msg.Data), err
}

func (c *Client) Publish(subject string, payload string) error {
	return c.client.Publish(subject, []byte(payload))
}

Which gets built into a binary:

$ xk6 build v0.31.1 --with github.com/username/xk6-nats-bridge="/home/username/go/src/github.com/username/xk6-nats-bridge"

Used in a script:

import { check } from 'k6';
import nats from 'k6/x/nats';
import * as faker from 'faker/locale/en_US';

export let options = {
  vus: 10,
  duration: '30s',
};

const natsTimeoutMS = 2000;
const natsServer = 'nats:4222';
const natsClient = new nats.Client(natsServer, natsTimeoutMS);

export default function () {
  const want = 'sample data'
  const payload = faker.name.findName()
  const subject = 'testSubject';
  var got = natsClient.request(subject, payload)
  check(got, {
    'Correct data received from NATS': (data) => data === want
  })

  const reportingSubject = 'reports.loadTest';
  natsClient.publish(reportingSubject, 'Tested OK!');
}

The script get bundled with webpack to include

When running the custom binary the proxy settings are set as env vars:

$ export http_proxy=http://proxy.domain.com
$ export HTTP_PROXY=http://proxy.domain.com
$ export https_proxy=http://proxy.domain.com
$ export HTTPS_PROXY=http://proxy.domain.com
$ k6 run main.js

The code works fine when running on my local kubernetes cluster (no proxy), but fails on another cluster that uses the proxy.

It fails with the following error:

time="2021-03-23T16:21:43Z" level=error msg="GoError: unexpected EOF\n\tat github.com/loadimpact/k6/js/common.Bind.func1 (native)\n\tat file:///main.js:1:3972(90)\n" executor=constant-vus scenario=default source=stacktrace

I know that xk6 is bleeding edge and experimental, but any pointers on what goes wrong, or how to increase logging will be much appreciated.

[mstoykov]

Hi @lhotrifork ,

I have no experience with nats, but from this docs it seems it is not HTTP based but just build on top of tcp. This means that setting HTTPS_PROXY will not help you.

Given this issue and PR, you should be able to tell the nats to go through a proxy by setting a custom dialer.

Hope this helps you.

I will close this as I don't think this is about the development of xk6 or anything that we can do. You are very much welcome though to open a thread on the community forum where I and others can still help you.