Question about running rails in Docker with shakapacker-dev-server locally #574

alex-tan · 2025-05-16T16:41:33Z

alex-tan
May 16, 2025

I'm running the shakapacker-dev-server with these options changed from the defaults:

  dev_server:
    host: 0.0.0.0
    allowed_hosts: "all"

The rails server has this environment variable set via: docker-compose.yml

SHAKAPACKER_ASSET_HOST: "http://host.docker.internal:3035"

I've connected to the rails docker container and confirmed it can connect to the dev server

curl 'host.docker.internal:3035'
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Error</title>
</head>
<body>
<pre>Cannot GET /</pre>
</body>
</html>

However when I try to load a Rails page that uses a javascript_pack_tag it's trying to compile the assets from scratch instead of using the dev-server:

Prepare JS assets with either:
1. Running `bin/shakapacker-dev-server`
2. Set `compile` to false in shakapacker.yml and run `bin/shakapacker -w`
[pid:1] [2d3737bf-6f3f-4854-8d08-04a7719567b4] [Shakapacker] Compiling...
[pid:1] [2d3737bf-6f3f-4854-8d08-04a7719567b4] [Shakapacker] 
COMPILATION FAILED:
EXIT STATUS: pid 61 exit 1

Am I using the config incorrectly for it to connect to the dev-server?

alex-tan · 2025-05-16T21:00:07Z

alex-tan
May 16, 2025
Author

Figured it out. Just needed to set SHAKAPACKER_DEV_SERVER_HOST: "host.docker.internal" for the rails container

And the following in the shakapacker.yml:

    host: 0.0.0.0
    allowed_hosts:
      - localhost
      - host.docker.internal

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Question about running rails in Docker with shakapacker-dev-server locally #574

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alex-tan May 16, 2025 Author

alex-tan
May 16, 2025

alex-tan
May 16, 2025
Author