Add counter metrics for client_login, refresh_token and code_to_token

[tlereste]

Motivation

To improve Keycloak observability @ Cdiscount (e-commerce platform), we need to add new gauge metrics with client_id and error informations.

This PR will also close the issue #59

What

Adding new gauge metrics :

• keycloak_client_logins
• keycloak_failed_client_login_attempts
• keycloak_refresh_tokens
• keycloak_refresh_tokens_errors
• keycloak_code_to_tokens
• keycloak_code_to_tokens_errors

Why

We need to have the client_id and error informations for theses metrics.

How

I added theses metrics based on the events :

• CLIENT_LOGIN
• CLIENT_LOGIN_ERROR
• REFRESH_TOKEN
• REFRESH_TOKEN_ERROR
• CODE_TO_TOKEN
• CODE_TO_TOKEN_ERROR

Verification Steps

1. Build the SPI from this branch and start Keycloak with it.
2. Login with client (grant_type = "client_credential")
3. Refresh a token (grant_type = "refresh_token")
4. Do a authorization (grant_type = "authorization_code")
5. Open the metrics endpoint in a browser.

Checklist:

• Code has been tested locally by PR requester
• Changes have been successfully verified by another team member

Progress

• Finished task

Additional Notes

NA

[clementcur]

Hi @pb82, any chance you can take a look?

[pb82]

Hey @clementcur , yep sorry. I was planning to make some time for the pull requests in this repo. I'll see if I can get through them today.

[pb82]

What exactly is a client_login and how does it differ from a normal login event (which already has a client label)?