Traefik Auth Middleware

This repository contains a Traefik middleware for authentication via Keycloak, with a local debug server to test it outside of Traefik.

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Structure

traefik-auth-middleware/
|── auth_test.go   # Unit tests
├── auth.go        # Middleware code
├── go.mod
└── debug/
    └── main.go    # Local debug server

• auth.go → middleware used by Traefik.
• debug/main.go → minimal HTTP server to test the middleware and view Keycloak responses.

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Dev setup

Install tools and dev dependencies

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mise install
mise run install_yaegi

Run tests

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mise run test

Format and lint the code

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mise run format
mise run lint

Running the debug server

1. Run the server:

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go run debug/.

2. The server listens on port 8080.

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Testing the middleware

Using curl:

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curl "http://localhost:8080?shop_name=test&api_key=secret"

Example response on success:

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{
  "message": "OK - middleware passed",
  "token": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI..."
}

If the request is malformed or authentication fails, the middleware returns an appropriate HTTP status code and an error message.

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Logs

The middleware outputs JSON logs to standard output:

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{
  "level": "INFO",
  "message": "Traefik-auth-middleware - Fetching auth token success for shop: test",
  "plugin_name": "sw-auth-plugin"
}

These logs allow you to track:

• The incoming request and its parameters
• The HTTP request to Keycloak
• Authentication success or failure

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Notes

• main.go is only used for local debugging.
• When using Traefik, running this server is not necessary.
• IAM variables must be configured in the Traefik config or via CreateConfig() for debugging.

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Debugging points

1. Ensure that the query params (shop_name and api_key) are present.
2. Check that the JSON logs show the HTTP request to Keycloak and the status code.
3. Using the debug server, you can directly see the Keycloak response in the HTTP response.

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Complete debug output example

Middleware debug server started on :8080
{"level":"INFO","message":"Traefik-auth-middleware - Fetching auth token success for shop: test","plugin_name":"sw-auth-plugin"}

HTTP Response:

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{
  "message": "OK - middleware passed",
  "token": "Bearer eyJhbGciOiJIUzI1NiIsInR5cCI..."
}