A trailing slash in the AI Gateway URL setting causes Duo Chat to return error A9999 because the AIGW returns 404 (#573787) · Issues · GitLab.org / GitLab · GitLab

A trailing slash in the AI Gateway URL setting causes Duo Chat to return error A9999 because the AIGW returns 404

During AIGW on EKS testing we [discovered](https://gitlab.com/gitlab-com/gl-infra/platform/runway/team/-/issues/589#note_2792701363) that when the AI Gateway URL is entered with a trailing slash (e.g., `https://ai-gateway-eks.us-east-1.aws.runway.gitlab.net/`), Duo Chat shows error `A9999` and associated AIGW logs show a request with two slashes: ```json { "url": "https://ai-gateway-eks.us-east-1.aws.runway.gitlab.net//v2/chat/agent", "path": "//v2/chat/agent", "status_code": 404, "method": "POST", ... } ``` ## Proposed fixes - [ ] Trim a trailing slash from the URL when it's input, either via the UI, environment variable, or `/etc/gitlab/gitlab.rb` - [ ] Use `URI.join` to [join the base URL with the path](https://gitlab.com/gitlab-org/gitlab/-/blob/e2e4348f269f790bfadbde73e41c52c703e52e7d/ee/lib/gitlab/duo/chat/step_executor.rb#L84)

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