changedetectionio unable to connect to playwright over docker - hostname issue

[rayoz12]

Describe the bug
changedetectionio unable to connect to playwright in docker, it looks like it has something to do with the Websocket used in the python playwright lib.

changedetection    | ERROR:changedetectionio:Exception reached processing watch UUID: d137082e-c565-442b-9a99-9ae7034e4500 - WebSocket error: getaddrinfo EAI_AGAIN chrome
changedetection    | =========================== logs ===========================
changedetection    | <ws connecting> ws://chrome:3000/
changedetection    | <ws error> [object Object]
changedetection    | <ws connect error> ws://chrome:3000/ getaddrinfo EAI_AGAIN chrome
changedetection    | <ws disconnected> ws://chrome:3000/ code=1006 reason=
changedetection    | ============================================================

Browserless/chrome / playwright itself is working because I can access it when exposing a port and a busybox container defined in the docker-compose can access it as well (with a wget)

Version
v0.39.15

To Reproduce

Steps to reproduce the behavior:

1. Enable playwright preview in the UI and in the docker-compose.yml (by defining PLAYWRIGHT_DRIVER_URL) and try to preview a website.

! ALWAYS INCLUDE AN EXAMPLE URL WHERE IT IS POSSIBLE TO RE-CREATE THE ISSUE - USE THE 'SHARE WATCH' FEATURE AND PASTE IN THE SHARE-LINK!

This works with all urls, I can't share a publicly accessible link because this is running on my LAN.

Expected behavior
changedetectionio is supposed to be able to connect to playwright. The WS error should also be more descriptive if possible to know exactly what's going on, although if it's part of the playwright lib not much can be done about that.

Screenshots

Desktop (please complete the following information):

• OS: Windows
• Browser Firefox
• Version: 102

Smartphone (please complete the following information):

• Device: [e.g. iPhone6]
• OS: [e.g. iOS8.1]
• Browser [e.g. stock browser, safari]
• Version [e.g. 22]

Additional context
Here's my docker-compose file for example. Variations really only for my notification network and deleting the options I don't need. It's also running behind a reverse proxy for access of the UI

version: '3.5'
services:
    changedetection:
        image: ghcr.io/dgtlmoon/changedetection.io
        container_name: changedetection
        hostname: changedetection
        volumes:
            - ./../../data/changedetection:/datastore

        environment:
  #        Default listening port, can also be changed with the -p option
  #      - PORT=5000

  #      - PUID=1000
  #      - PGID=1000
  #
  #       Alternative Playwright URL, do not use "'s or 's!
            - PLAYWRIGHT_DRIVER_URL=ws://playwright-chrome:3000/
  #
  #       Playwright proxy settings playwright_proxy_server, playwright_proxy_bypass, playwright_proxy_username, playwright_proxy_password
  #
  #             https://playwright.dev/python/docs/api/class-browsertype#browser-type-launch-option-proxy
  #
  #        Plain requsts - proxy support example.
  #      - HTTP_PROXY=socks5h://10.10.1.10:1080
  #      - HTTPS_PROXY=socks5h://10.10.1.10:1080
  #
  #        An exclude list (useful for notification URLs above) can be specified by with
  #      - NO_PROXY="localhost,192.168.0.0/24"
  #
  #        Base URL of your changedetection.io install (Added to the notification alert)
            - BASE_URL=url

  #        Respect proxy_pass type settings, `proxy_set_header Host "localhost";` and `proxy_set_header X-Forwarded-Prefix /app;`
  #        More here https://github.com/dgtlmoon/changedetection.io/wiki/Running-changedetection.io-behind-a-reverse-proxy-sub-directory
  #      - USE_X_SETTINGS=1

      # Comment out ports: when using behind a reverse proxy , enable networks: etc.
        # ports:
        #     - 5000:5000
        restart: unless-stopped
        networks:
            - reverse_proxy
            - gotify


    playwright-chrome:
        hostname: playwright-chrome
        container_name: playwright-chrome
        image: browserless/chrome
        restart: unless-stopped
        ports:
            - 1337:3000
        environment:
            - SCREEN_WIDTH=1920
            - SCREEN_HEIGHT=1024
            - SCREEN_DEPTH=16
            - ENABLE_DEBUGGER=false
            - PREBOOT_CHROME=true
            - CONNECTION_TIMEOUT=300000
            - MAX_CONCURRENT_SESSIONS=10
            - CHROME_REFRESH_TIME=600000
            - DEFAULT_BLOCK_ADS=true
            - DEFAULT_STEALTH=true

    busybox:
        hostname: busybox
        container_name: busybox
        image: busybox
        restart: unless-stopped
        command: sleep infinity

networks:
  gotify:
    external:
        name: gotify
  reverse_proxy:
    external: 
        name: reverse_proxy

[dgtlmoon]

This is NOT a bug, this is a local configuration issue, please do not spam the issue queue

    playwright-chrome:
        hostname: playwright-chrome

It is 100% verbose enough, it cannot hold your hand more I think

changedetection    | ERROR:changedetectionio:Exception reached processing watch UUID: d137082e-c565-442b-9a99-9ae7034e4500 - WebSocket error: getaddrinfo EAI_AGAIN chrome
changedetection    | =========================== logs ===========================
changedetection    | <ws connecting> ws://chrome:3000/

Something in your config is causing it to look at chrome hostname instead of playwright-chrome, maybe restart/recreate the service

[rayoz12]

Sorry that was an old log and I wasn't trying to spam. I'm not trying to waste your time and I've looked into it but it can't connect to the chrome container for some reason. Internet searches suggest it's a DNS issue within docker but other containers (like busybox above) can connect to playwright. I can't debug in the container itself because of a lack of curl and wget.

Would you also have any idea on how to expand the JSON error in the logs to actually see what the problem is?

=========================== logs ===========================
changedetection      | <ws connecting> ws://playwright-chrome:3000/
changedetection      | <ws error> [object Object]

[dgtlmoon]

converted to discussion and renamed the title of your post - please do not spam the issue queue

[rayoz12]

#627
Talks about the issue.

The issue being that an explicit bridge network needs to be created to refer the container name (the docker-compose version might also be a factor):

version: '3.5'
services:
    changedetection:
        ...
        networks:
            - changedetection
        ...


    playwright-chrome:
        ...
        networks:
            - changedetection
        ...

networks:
  changedetection:
    name: changedetection

[rayoz12]

I think that might be a good start. I think on older versions of docker compose (v2) it works implicitly and it's no issues (but I haven't tested), but for me in my environment I had to use v3.5 and I think that needs an explicit network. Maybe whenever you need to update the version and file that could be added.

[martinorob]

Hi Guys,
i have opened an issue #979
but now is closed.
I have the same error code=1006
but even with the @rayoz12 docker-compose doesn’t works.

May you help me?
Thanks

[bencollinz]

Hi Guys, i have opened an issue #979 but now is closed. I have the same error code=1006 but even with the @rayoz12 docker-compose doesn’t works.

May you help me? Thanks

Yea, this 'answer' doesn't work for me either.
same error code 1006. Been trying to get this working for almost a year now

[rayoz12]

1006 is a general error that means the client closed the connection, so it can mean almost anything. I would prefer it if you looked at the entire problem and solution in context before coming to an incorrect conclusion and trying to discredit what I've shown here.

[soraxas]

I can confirm that following @rayoz12 's suggestion and adding a bridge network does helps my case