Resolve "Track the number of new Redis connections per transaction"
## What does this MR do?
Add a new metric counter, `new_redis_connections`, that contains the number of calls to `Redis::Client#connect` in the current transaction.
## Are there points in the code the reviewer needs to double check?
Not sure. I tested this in kind of a brute-force way:
1. Add a debugger in the monkey-patched `connect` method.
2. With metrics enabled, start the app and load a page.
3. The first Redis connection is created by `Rack::Attack` and isn't in a transaction, but still works fine.
4. The second Redis connection is within a transaction (the page load), and increments the counter.
5. If I reload the page, neither debugger is hit.
6. If I use a Redis client and do `CLIENT KILL` on my two existing clients, then reload the page, I get 3 and 4 again.
7. If I disable metrics collection, the debugger never gets hit.
## Why was this MR needed?
We may have a Redis connection leak somewhere, so adding metrics will let us track this.
## What are the relevant issue numbers?
Closes#18451.
## Screenshots (if relevant)
Hahaha nope, not relevant.
## Does this MR meet the acceptance criteria?
- [ ] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [ ] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [ ] API support added
- [ ] Tests
- [ ] Added for this feature/bug
- [ ] All builds are passing
- [ ] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [ ] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [ ] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)
cc @yorickpeterse
See merge request !4649
Improve Gitlab::Auth method names
Auth.find was a very generic name for a very specific method.
Auth.find_in_gitlab_or_ldap was inaccurate in GitLab EE where it also
looks in Kerberos.
See merge request !4589
It doesn't seem possible to set constraints based on format for project
IDs ending in .git, so set the constraint on the ID and ensure the
format is nil to avoid the case where the project ID is something like
project.git.foo.
* commit 'ca3c5c295ed653b483fe81c3918ffe60f46666b9':
Let contributors know where to start
Ensure branch cleanup regardless of whether the import process succeeds
Fix failing todo tests
Reorder the todos because the use of the project finder attempts to order them differently
Update target todo test to use a public project
Use the project finder in the todos finder to limit todos to just ones within projects you have access to.
Move filtering todos by projects not pending deletion into a scope on the todo model
Reduce the filters on the todos joins project query by being explicit about the join
Ensure we don't show TODOS for projects pending delete
Fix deprecation warnings in spec/services/issues/bulk_update_service_spec.rb
Remove unused Issuable#is_assigned? method
fixup! Don't allow merges with new commits
fixup! Add `sha` parameter to MR accept API
Reduce Namespace queries in UserReferenceFilter
Added ReferenceFilter#nodes
Returning enums in ReferenceFilter#each_node
Don't allow merges with new commits
Add `sha` parameter to MR accept API
The `sha` parameter is optional, and when present, must match the
current HEAD SHA of the source branch. Otherwise, the API call fails
with a 409 Conflict and a message containing the current HEAD for the
source branch.
Also tidy up some doc wording.
Douwe Maan
Sean McGivern
Kamil Trzcinski
Douglas Barbosa Alexandre
Stan Hu
Rémy Coutable
Jacob Vosmaer
Rui AndersonandRémy Coutable
Z.J. van de Weg
Felipe Artur
Grzegorz BizonandRobert Speicher
Connor Shea
