gitlab-CI: WebSocketException: Connection to 'http://127.0.0.1:33655#' was not upgraded to websocket

[boldt]

Hint: I cross-posted this issue also on flutter/flutter#83344, since I don't know whether it's a flutter issue or an issue with the docker-image.

Environment

• Flutter 2.2.0
• Gitlab CI

Steps to Reproduce

I created the standard "getting started" app:

flutter create flutter_test_mwe

On our local machines, we can run flutter test, which succeeds:

Now, we want to build the app with gitlab-CI. We're using the image cirrusci/flutter:2.2.0:

variables:
  FLUTTER_VERSION: 2.2.0

stages:
  - build
  - deploy

build_and_test_job:
  stage: build
  image: cirrusci/flutter:$FLUTTER_VERSION
  script:
    - flutter pub get
    - flutter test
    - flutter build apk
  tags:
    - docker
  only:
    - merge_requests

Now, flutter testcrashes with the error:

WebSocketException: Connection to 'http://127.0.0.1:33655#' was not upgraded to websocket

[fkorotkov]

Looks more like an issue with your GitLab setup. Will be great if it can be reproduced locally in a docker container. Will be great if you can try 0.0.0.0 and localhost instead of 127.0.0.1.

[boldt]

I would like to help you to reproduce this issue.

To do so...

• I would like to unserstand, why "flutter test" tries to open a WebSocket-connection, and
• How do I configre "flutter test" use another IP?

[fkorotkov]

We can try to repro locally in a Docker container by using Cirrus CLI. Once you install it you can create .cirrus.yml in your repo with the following content:

env:
  FLUTTER_VERSION: 2.2.0

test_task:
  container:
    image: cirrusci/flutter:$FLUTTER_VERSION
  script:
    - flutter pub get
    - flutter test
    - flutter build apk

Once you have it you can try to run cirrus run and see if it's working. If it is, it means your host has some issue with Docker configuration and networking. You are using a self-hosted runner, right?

[fkorotkov]

Closing because of inactivity and not enough information to reproduce 😪

[boldt]

We solved it.

Our gitlab-runner runs behind a corporate proxy server, thus PROXY variables were mapped into the runner.
Unfortunately, we forgot to add localhost to the NO_PROXY variable, thus the runner tried to resolve localhost at the proxy server.

[JordanRoberts1]

@boldt where did you add localhost to the NO_PROXY variable?

I'm running into this same issue, although using action, subosito/flutter-action@v2.2.0, not docker image, cirrusci/flutter.

I have systemProp.https.nonProxyHosts=localhost|127.0.0.1 in android/gradle.properties