Tracking of custom events

GitLab Performance Monitoring is now able to track custom events not
directly related to application performance. These events include the
number of tags pushed, repositories created, builds registered, etc.

The use of these events is to get a better overview of how a GitLab
instance is used and how that may affect performance. For example, a
large number of Git pushes may have a negative impact on the underlying
storage engine.

Events are stored in the "events" measurement and are not prefixed with
"rails_" or "sidekiq_", this makes it easier to query events with the
same name triggered from different parts of the application. All events
being stored in the same measurement also makes it easier to downsample
data.

Currently the following events are tracked:

* Creating repositories
* Removing repositories
* Changing the default branch of a repository
* Pushing a new tag
* Removing an existing tag
* Pushing a commit (along with the branch being pushed to)
* Pushing a new branch
* Removing an existing branch
* Importing a repository (along with the URL we're importing)
* Forking a repository (along with the source/target path)
* CI builds registered (and when no build could be found)
* CI builds being updated
* Rails and Sidekiq exceptions

Fixes gitlab-org/gitlab-ce#13720

1 files changed, 57 insertions, 0 deletions

diff --git a/spec/lib/gitlab/metrics/transaction_spec.rb b/spec/lib/gitlab/metrics/transaction_spec.rb
index f1a191d9410..3887c04c832 100644
--- a/spec/lib/gitlab/metrics/transaction_spec.rb
+++ b/spec/lib/gitlab/metrics/transaction_spec.rb
@@ -142,5 +142,62 @@ describe Gitlab::Metrics::Transaction do
 
       transaction.submit
     end
+
+    it 'does not add an action tag for events' do
+      transaction.action = 'Foo#bar'
+      transaction.add_event(:meow)
+
+      hash = {
+        series:    'events',
+        tags:      { event: :meow },
+        values:    { count: 1 },
+        timestamp: an_instance_of(Fixnum)
+      }
+
+      expect(Gitlab::Metrics).to receive(:submit_metrics).
+        with([hash])
+
+      transaction.submit
+    end
+  end
+
+  describe '#add_event' do
+    it 'adds a metric' do
+      transaction.add_event(:meow)
+
+      expect(transaction.metrics[0]).to be_an_instance_of(Gitlab::Metrics::Metric)
+    end
+
+    it "does not prefix the metric's series name" do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.series).to eq(described_class::EVENT_SERIES)
+    end
+
+    it 'tracks a counter for every event' do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.values).to eq(count: 1)
+    end
+
+    it 'tracks the event name' do
+      transaction.add_event(:meow)
+
+      metric = transaction.metrics[0]
+
+      expect(metric.tags).to eq(event: :meow)
+    end
+
+    it 'allows tracking of custom tags' do
+      transaction.add_event(:meow, animal: 'cat')
+
+      metric = transaction.metrics[0]
+
+      expect(metric.tags).to eq(event: :meow, animal: 'cat')
+    end
   end
 end