Using Apache 2.4.7 on Ubuntu 14.04.4. Gitlab SSL configuration derived from https://gitlab.com/gitlab-org/gitlab-recipes/blob/master/web-server/apache/gitlab-omnibus-ssl-apache24.conf; copied and modified for Mattermost as well.
When a user navigates to https://mattermost.servername.com, a sign-in screen is presented. The button to "Login via Gitlab" is shown. Clicking this button initiates a request to https://mattermost.servername.com/api/v3/oauth/gitlab/signup, which returns a 302 Redirect to: https://gitlab.servername.com/oauth/authorize?response_type=code&client_id=xxxx&redirect_uri=http%3A%2F%2Fmattermost.servername.com%3A4443%2Fsignup%2Fgitlab%2Fcomplete&state=xxxx. Notice that the redirect_uri is missing the 's' for HTTPS. This causes the loaded Gitlab page to return "The redirect URI included is not valid."
Relevant gitlab.rb lines:
mattermost_external_url 'https://mattermost.servername.com'
mattermost['enable'] = true
mattermost['service_use_ssl'] = true
mattermost['service_address'] = "127.0.0.1"
mattermost['service_port'] = "8065"
mattermost_nginx['enable'] = false
mattermost_nginx['redirect_http_to_https'] = true # this likely does nothing
How can I fix the redirect_uri that is presented by the main Mattermost login page?