ECONNREFUSED errors when using Artillery to test a Deno HTTP server

[GJZwiers]

I am trying to use Artillery with a Deno HTTP server, but this results in a lot of ECONNREFUSED errors.

My artillery.yaml file:

config:
  target: "http://localhost:8000"
  phases:
    - duration: 60
      arrivalRate: 5
      name: Warm up
    - duration: 120
      arrivalRate: 5
      rampTo: 50
      name: Ramp up load
    - duration: 600
      arrivalRate: 50
      name: Sustained load

scenarios:
  - name: "get hello"
    flow:
      - get:
          url: "/"

Deno server code:

import { opine } from "https://deno.land/x/opine@2.2.0/mod.ts";
const app = opine();

app.get("/", function (req, res) {
  res.send("Hello World");
});

app.listen(8000);

Output:

> artillery run .\artillery.yaml
Phase started: Warm up (index: 0, duration: 60s) 09:49:10(+0200)

--------------------------------------
Metrics for period to: 09:49:20(+0200) (width: 8.002s)
--------------------------------------

errors.ECONNREFUSED: ........................................................... 45
http.request_rate: ............................................................. 5/sec
http.requests: ................................................................. 45
vusers.created: ................................................................ 45
vusers.created_by_name.get hello: ................................................. 45
vusers.failed: ................................................................. 45

If I start a similar server in Node, everything is fine:

const express = require('express');
const app = express();

app.get('/', function (req, res) {
  res.send('Hello World')
})

app.listen(8000);

Phase started: Warm up (index: 0, duration: 60s) 09:51:01(+0200)

--------------------------------------
Metrics for period to: 09:51:10(+0200) (width: 7.004s)
--------------------------------------

http.codes.200: ................................................................ 40
http.request_rate: ............................................................. 5/sec
http.requests: ................................................................. 40
http.response_time:
  min: ......................................................................... 1
  max: ......................................................................... 9
  median: ...................................................................... 2
  p95: ......................................................................... 7.9
  p99: ......................................................................... 8.9
http.responses: ................................................................ 40
vusers.completed: .............................................................. 40
vusers.created: ................................................................ 40
vusers.created_by_name.get hello: ................................................. 40
vusers.failed: ................................................................. 0
vusers.session_length:
  min: ......................................................................... 2.5
  max: ......................................................................... 26.6
  median: ...................................................................... 4.2
  p95: ......................................................................... 25.8
  p99: ......................................................................... 25.8

In Deno the errors are happening for various server frameworks so it is not a problem with the opine server. The debug output shows the following requests and responses for the Node server, while nothing except the errors are shown for the Deno server:

2022-07-07T19:57:12.467Z http request: {
  "url": "http://localhost:8000/",
  "method": "GET",
  "headers": {
    "user-agent": "Artillery (https://artillery.io)"
  }
}

2022-07-07T19:57:12.467Z http:response "Hello World"
2022-07-07T19:57:12.467Z http:response {
  "x-powered-by": "Express",
  "content-type": "text/html; charset=utf-8",
  "content-length": "11",
  "etag": "W/\"b-Ck1VqNd45QIvq3AZd8XYQLvEhtA\"",
  "date": "Thu, 07 Jul 2022 19:57:12 GMT",
  "connection": "keep-alive",
  "keep-alive": "timeout=5"
}

I do not know if this is a problem in Deno or Artillery, but I thought I would post this issue here first. Here is my artillery version:

VERSION INFO:

Artillery Core: 2.0.0-20
Artillery Pro:  not installed (https://artillery.io/product)

Node.js: v18.1.0
OS:      win32

[juanig1]

Hey, did you figure this out?
Seems like a Deno config issue, as the script is correct and it works with Node (also working fine against netcat in my machine)

[GJZwiers]

Changing the target to http://127.0.0.1:8000 instead of localhost made it work. :) Since it's definitely not an issue with Artillery I will close this now.

[nicotrozzo]

Same was happening to me with an express server, changing to 127.0.0.1 solved it. Thanks for sharing!

[harsh-sri]

thanks for sharing it 👍