Previously, we called the `peek_enabled?` method like so:
prepend_before_action :set_peek_request_id, if: :peek_enabled?
Now we don't have a `set_peek_request_id` method, so we don't need that
line. However, the `peek_enabled?` part had a side-effect: it would also
populate the request store cache for whether the performance bar was
enabled for the current request or not.
This commit makes that side-effect explicit, and replaces all uses of
`peek_enabled?` with the more explicit
`Gitlab::PerformanceBar.enabled_for_request?`. There is one spec that
still sets `SafeRequestStore[:peek_enabled]` directly, because it is
contrasting behaviour with and without a request store enabled.
The upshot is:
1. We still set the value in one place. We make it more explicit that
that's what we're doing.
2. Reading that value uses a consistent method so it's easier to find in
future.
In dev environments, Sidekiq was encountering the message:
Circular dependency detected while autoloading constant Gitlab::Profiler
This saves some overhead during normal usage.
1. The output isn't great. It can be hard to find hotspots and, even
when you do find them, to find why those are hotspots.
2. It uses some jQuery-specific frontend code which we can remove now
that we don't have this any more.
3. It's only possible to profile the initial request, not any subsequent
AJAX requests.
This uses an ActiveRecord subscriber to get queries and calculate the
total query time from that. This means that the total will always be
consistent with the queries in the table. It does however mean that we
could potentially miss some queries that don't go through ActiveRecord.
Making this change also allows us to unify the response JSON a little
bit, making the frontend slightly simpler as a result.
peek-redis resets its counters at the start of an ActionController
notification (`start_processing.action_controller`), which causes it to
miss some Redis queries that precede it, such as the database load
balancer and Rack Attack queries. This produces inconsistencies in the
performance bar between the number of calls and their durations with the
actual calls in the detailed view.
We fix this by getting rid of peek-redis in favor of consolidating all
logic into the `RedisDetailed` view, which tracks Redis queries using
`RequestStore`. This has the nice property of removing thread-specific
counters as well.
Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/64707
