Geo: Tell Git HTTP pushers that they are missing out on Git pull lag messages

Problem to solve

Since replication lag messages on Git requests are useful, and since we are unable to notify users about replication lag on Git pull over HTTP, we should add a message on Git push over HTTP that communicates this limitation.

Intended users

• Developers
• System Administrators

Further details

Proposal

• Blocked on https://gitlab.com/gitlab-org/gitlab-ee/issues/9195
• Blocked on https://gitlab.com/gitlab-org/gitlab-ee/issues/14631
• Add more text (see acceptance criteria below) to the replication lag message on Git push over HTTP.
• Add documentation explaining replication lag, especially targeting users that are following the doc link given in the lag message

Permissions and Security

Documentation

Testing

What does success look like, and how can we measure that?

$ git push
warning: redirecting to http://localhost:3001/-/geo-node-referrer/4/twitter/typeahead-js.git/
Enumerating objects: 5, done.
Counting objects: 100% (5/5), done.
Delta compression using up to 8 threads
Compressing objects: 100% (3/3), done.
Writing objects: 100% (3/3), 992 bytes | 992.00 KiB/s, done.
Total 3 (delta 2), reused 0 (delta 0)
remote: Current replication lag: 5 seconds
remote: This lag message is not sent on git pull over HTTP due to protocol
remote: limitations. You can change your remote to use git over SSH to receive
remote: current replication lag on git pull. See DOCUMENTATION_LINK for more 
remote: information.
To http://localhost:3002/twitter/typeahead-js.git
   f0eb611..1f1bcf0  master -> master

What is the type of buyer?

• Premium
• Ultimate

Links / references