GitLab HTTP Router prevents Action Cable from connecting to localhost

Overview

With GDK hostname set to localhost, Action Cable cannot connect. The following errors are shown in the browser console:

actioncable_link.js:10 WebSocket connection to 'ws://localhost:3000/-/cable' failed:

When disabling the gitlab_http_router, Action Cable can connect again.

Impacted categories

The following categories relate to this issue:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Steps to replicate (optional)

Proposal (optional)

Environment (optional)

• Operating system name: <!-- output of `uname -a` command -->
• Architecture: <!-- output of `arch` command -->
• The contents of your gdk.yml (if any)
• Ruby version: <!-- output of `ruby --version` command -->
• GDK version: c1604b63