Feat/variables

[spinecow]

Context

This PR enhances the authentication system by adding comprehensive logging to help diagnose authentication issues. The primary goal is to provide better visibility into the credential parsing and authentication process without changing the core functionality. This will help administrators quickly identify and resolve authentication problems in production environments.

The PR also maintains full compatibility with the new JSON format for credentials that was recently implemented, ensuring that existing deployments continue to work correctly.

Choices

I solved this by adding detailed logging at key points in the authentication flow:

1. Credential Loading: Added logging when credentials are loaded from the environment variable, including the number of credentials parsed and details about each credential (without exposing sensitive information).

2. Authentication Attempts: Added logging for each authentication attempt, including the username (but not password) and the result of the authentication.

3. Authorization Results: Added logging for successful authorizations and various failure modes (missing credentials, invalid username, invalid password, expired credentials).

4. File Serving: Added logging when the M3U file is served, which helps confirm successful authentication.

This approach was chosen because:

• It provides comprehensive visibility into the authentication process without changing the core logic
• It maintains security by not logging sensitive information like passwords
• It helps administrators quickly diagnose authentication issues in production
• It has minimal performance impact as the logging is only enabled when DEBUG is true
• It maintains full backward compatibility with existing deployments

Test instructions

1. Environment Setup:

   • Set up the application with the new JSON format for credentials:
     CREDENTIALS='[{"username":"user1","password":"pass1","expiration":"2026-02-01T00:00:00Z"},{"username":"user2","password":"pass2"}]'
   • Enable debug logging with DEBUG=true

2. Authentication Testing:

   • Test with valid credentials: curl "http://localhost:PORT/playlist.m3u?username=user2&password=pass2"
   • Test with invalid credentials: curl "http://localhost:PORT/playlist.m3u?username=user2&password=wrongpass"
   • Test with missing credentials: curl "http://localhost:PORT/playlist.m3u"
   • Test with expired credentials: curl "http://localhost:PORT/playlist.m3u?username=user1&password=pass1" (if the expiration date has passed)

3. Log Verification:

   • Check that the logs show credential loading with the correct number of credentials
   • Verify that authentication attempts are logged with appropriate information
   • Confirm that successful authentications and failures are clearly distinguishable in the logs
   • Ensure that sensitive information like passwords is not exposed in the logs

Checklist before requesting a review

• I have performed a self-review of my code
• I've added documentation about this change to the README (the README already had documentation about the JSON format)
• I've not introduced breaking changes (this change is backward compatible)

[sonroyaalmerol]

Thanks for this! Do you mind resolving the failing test cases for me? I'll see if I can merge this over the weekend.