LABEL_STUDIO_HOST environment variable is not respected in all places

[thomasquandago]

Describe the bug
We are hosting Label Studio on our own domain with a base path, for example: https://example.com/basepath/. This works really well. There are two files, and one endpoint which does not respect the base path.

To Reproduce
Steps to reproduce the behavior:

1. Login to Label Studio
2. Open the inspector and go to network tab
3. Go to the home page / and refresh.
4. You will see that the following http requests do not respect the base path:

• GET https://example.com/static/fonts/Figtree-Regular.ttf
• GET https://example.com/static/fonts/Figtree-SemiBold.ttf
• GET https://example.com/heidi-tips

Expected behavior
I would expect the requests to be sent to:

• GET https://example.com/basepath/static/fonts/Figtree-Regular.ttf
• GET https://example.com/basepath/static/fonts/Figtree-SemiBold.ttf
• GET https://example.com/basepath/heidi-tips

This does work for the Favicon for example, which is correctly sent to:
/basepath/static/images/favicon.8992b8aa4126.ico

Screenshots
If applicable, add screenshots to help explain your problem.

Environment (please complete the following information):

• OS: Windows + Firefox. Label studio is hosted on Linux via ECS.
• Label Studio Version Tested 1.22.0 and 1.23.0

Additional context
Snippet from terraform. These values are set as environment variables.

    environment_variables = {
      LABEL_STUDIO_HOST    = "https://example.com/basepath"
      CSRF_TRUSTED_ORIGINS = "https://example.com/"

      LABEL_STUDIO_DATABASE = "postgresql"
      DJANGO_DB             = "default"
      POSTGRE_NAME          = local.operable_label_studio_database

      POSTGRE_HOST = ""
      POSTGRE_PASSWORD = ""
      POSTGRE_PORT = ""

      LABEL_STUDIO_DISABLE_SIGNUP_WITHOUT_LINK = "true"
    }

[heidi-humansignal]

Hello,

Thank you for contacting Label Studio,

This might be a limitation from our end where some requests still go to the root / instead of the prefixed path. Do you happen to use an NGINX or any form of reverse proxy ?

Best Regards!

Comment by Oussama Assili
Workflow Run

[thomasquandago]

The first point is the exact problem looking at the code. I am using ALB to put Label Studio on the designated subpath, but those requests are sent to a different application due to the incorrect assumption of those requests that the application is hosted at the root.