Self-hosted Gitlab Integration not Working

[necouchman]

I think this has been reported in the past, but I'm still unable to get a self-hosted version of DrawIO to integrate correctly with a self-hosted version of Gitlab for storing diagrams.

Environment

• Gitlab CE running on Rocky Linux 9
• DrawIO running in a Pod in OKD 4.19 (Kubernetes 1.32.5)
  • Image is jgraph/drawio:latest

Process

• Gitlab is installed and running, I can successfully log in, have repos, etc.
• Create an application in Gitlab called "DrawIO" and set the callback URL to https://diagrams.apps.okd.local/gitlab.html
• Create the Gitlab pod with the following details:
  • Create a custom service account with the "anyuid" privilege
  • Set the runAsUser and runAsGroup parameters for the DrawIO container.
  • Set the DRAWIO_GITLAB_URL an DRAWIO_GITLAB_ID variables to the URL of my Gitlab instance and the application ID created above.
  • Set image to jgraph/drawio:latest
• Open the https://diagrams.apps.okd.local URL, and the DrawIO application launches successfully.
• From the File menu within the web application, select Open From -> Gitlab
• Click the Authorize button when it appears.
• Receive the error from Gitlab: The redirect URI included is not valid.
• Upon examining the URL, note that the ".html" is missing from the end of the "gitlab" portion in the diagrams redirect:
  • Expected value: &redirect_uri=https%3A%2F%2Fdiagrams.apps.okd.local%2Fgitlab.html&response_type=
  • Observed value: &redirect_uri=https%3A%2F%2Fdiagrams.apps.okd.local%2Fgitlab&response_type=
• By manually adding the .html to the end of the redirect_uri argument, the authorization appears to succeed and the page closes.
• However, in the DrawIO window an error appears: Access Denied with a Try Again and Cancel button.
• If, instead, I change the URL of the application to not include the .html, the redirect back to the DrawIO page fails with HTTP 500.