Feature Request: Support environment variables for default user in Docker deployments

[xmha97]

Description:
Currently Radicale requires manual configuration of authentication via a users file or config file. In Docker-based deployments, especially for quick self-hosted setups, it would be very useful to allow defining a default user through environment variables.

This would simplify initial setup and make Radicale more suitable for automated deployment environments (e.g. Docker Compose, Kubernetes, homelabs).

Proposed feature:
Support environment variables such as:

• RADICALE_USER
• RADICALE_PASSWORD (or RADICALE_PASS)

These variables could automatically generate or populate an htpasswd-compatible authentication backend on container startup.

Example usage in docker-compose:

environment:
  - RADICALE_USER=admin
  - RADICALE_PASSWORD=securepassword

Expected behavior:

• On first startup, if authentication is enabled and no users file exists:

  • Automatically create htpasswd file with provided credentials

• If users file already exists, environment variables are ignored (or optionally used only to append users)

Why this is useful:

• Enables “one-command” setup for Radicale
• Reduces need for manual config file + htpasswd setup
• Improves usability in Docker-based self-hosting environments
• Aligns with existing unofficial Docker images that already implement similar behavior

Alternative considered:

• Using only config file + htpasswd (current approach)

  • Works, but not ideal for ephemeral containers or automated deployment

Additional context:
Some community Docker images already implement similar environment variables (e.g. RADICALE_USER, RADICALE_PASS), which shows demand for this feature.

[pbiering]

Beside that with suggested data a htpasswd file containing cleartext credential should be created, what is the purpose of such single-user-only "one-command" installation (potentially without any persistency)?

"radicale" itself has currently no capability to create or manipulate htpasswd and there also no plans for it to implement - so such feature must be implemented by the container startup script.

If users file already exists, environment variables are ignored (or optionally used only to append users)

"append" would require that the file stays persistent - why not simply generating your config and htpasswd file outside of the container with all your needs (and e.g. hashed secret) and map it into, similar to the "collection root" folder to avoid loss of data on container shutdown.

@kalsi-avneet : your thoughts?

[kalsi-avneet]

Hi @xmha97,

Thank you for the feature request.

Automatically create htpasswd file with provided credentials

This is an interesting idea, but as you might know, htpasswd file is just one of the multiple authentication methods. Please see this documentation for more methods: https://radicale.org/v3.html#auth.

I believe it might be complex from user experience point of view to support all of them as per the proposal.

This would simplify initial setup and make Radicale more suitable for automated deployment environments (e.g. Docker Compose, Kubernetes, homelabs).

As @pbiering suggested, would it be possible in your usecase to generate the required files outside of the container, and then mounting them?

Works, but not ideal for ephemeral containers or automated deployment

I believe that the above approach (generating required files outside of container and mounting them) will work for these cases too.

Please share some more details about your setup and requirements. I will be glad to support further.