The change in
https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/24199 caused
requests coming from a load balancer to arrive as 127.0.0.1 instead of
the actual IP.
`Rack::Request#ip` behaves slightly differently different than
`ActionDispatch::Request#remote_ip`: the former will return the first
X-Forwarded-For IP if all of the IPs are trusted proxies, while the
second one filters out all proxies and falls back to REMOTE_ADDR, which
is 127.0.0.1.
For now, we can revert back to using `Rack::Request` because these
middlewares don't manipulate parameters. The actual fix problem involves
fixing Rails: https://github.com/rails/rails/issues/28436.
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/58573
As mentioned in
https://gitlab.com/gitlab-org/gitlab-ee/issues/9035#note_129093444,
Rails 5 switched ActionDispatch::Request so that it no longer inherits
Rack::Request directly. A middleware that uses Rack::Request to
read the environment may see stale request parameters if
another middleware modifies the environment via ActionDispatch::Request.
To be safe, we should be using ActionDispatch::Request everywhere.
Stan Hu