There seem to be a lot of cases where the suffix of an action (e.g.
".html") is set to bogus data, such as "*/*" or entire URLs. This can
increase cardinality of our metrics, and isn't very useful for
monitoring and filtering. To work around this, we enforce a whitelist
containing a few suffixes we actually care about. Suffixes not supported
will be grouped under the action without a suffix. This means that a
request to "FooController#bar.jpeg" will be assigned to
"FooController#bar".
Certain controllers (e.g. Doorkeeper::TokensController) don't expose the
method "request_format". This commit changes
Gitlab::Metrics::WebTransaction so we don't rely on this method, instead
using the underlying code this method uses.
Fixes https://gitlab.com/gitlab-org/gitlab-ce/issues/46412
The method "content_type" on a controller does not always return the
correct content type. On the other hand, the method "request_format"
does _and_ immediately returns a Symbol (e.g. :json) instead of a
mime-type name (e.g. application/json). With these changes metrics
should again report their action names correctly.
Fixes https://gitlab.com/gitlab-com/infrastructure/issues/3499
