Merge branch 'custom-events-tracking' into 'master'

Tracking of custom events

## What does this MR do?

This MR adds the ability to track custom events such as the number of Git pushes.

## Are there points in the code the reviewer needs to double check?

The usual stuff.

## Why was this MR needed?

We want to track more business level data such as the number of Git pushes, how many repositories are imported (and from where), etc.

## What are the relevant issue numbers?

gitlab-org/gitlab-ce#13720

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] ~~API support added~~
- Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

cc @pcarranza 

See merge request !5830

5 files changed, 130 insertions, 2 deletions

diff --git a/spec/lib/gitlab/metrics/metric_spec.rb b/spec/lib/gitlab/metrics/metric_spec.rb
index f718d536130..f26fca52c50 100644
--- a/spec/lib/gitlab/metrics/metric_spec.rb
+++ b/spec/lib/gitlab/metrics/metric_spec.rb
@@ -23,6 +23,24 @@ describe Gitlab::Metrics::Metric do
     it { is_expected.to eq({ host: 'localtoast' }) }
   end
 
+  describe '#type' do
+    subject { metric.type }
+
+    it { is_expected.to eq(:metric) }
+  end
+
+  describe '#event?' do
+    it 'returns false for a regular metric' do
+      expect(metric.event?).to eq(false)
+    end
+
+    it 'returns true for an event metric' do
+      expect(metric).to receive(:type).and_return(:event)
+
+      expect(metric.event?).to eq(true)
+    end
+  end
+
   describe '#to_hash' do
     it 'returns a Hash' do
       expect(metric.to_hash).to be_an_instance_of(Hash)
diff --git a/spec/lib/gitlab/metrics/rack_middleware_spec.rb b/spec/lib/gitlab/metrics/rack_middleware_spec.rb
index f264ed64029..a30cb2a5e38 100644
--- a/spec/lib/gitlab/metrics/rack_middleware_spec.rb
+++ b/spec/lib/gitlab/metrics/rack_middleware_spec.rb
@@ -45,6 +45,15 @@ describe Gitlab::Metrics::RackMiddleware do
 
       middleware.call(env)
     end
+
+    it 'tracks any raised exceptions' do
+      expect(app).to receive(:call).with(env).and_raise(RuntimeError)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:add_event).with(:rails_exception)
+
+      expect { middleware.call(env) }.to raise_error(RuntimeError)
+    end
   end
 
   describe '#transaction_from_env' do
diff --git a/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb b/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
index 4d2aa03e722..acaba785606 100644
--- a/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
+++ b/spec/lib/gitlab/metrics/sidekiq_middleware_spec.rb
@@ -12,7 +12,9 @@ describe Gitlab::Metrics::SidekiqMiddleware do
         with('TestWorker#perform').
         and_call_original
 
-      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).with(:sidekiq_queue_duration, instance_of(Float))
+      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).
+        with(:sidekiq_queue_duration, instance_of(Float))
+
       expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:finish)
 
       middleware.call(worker, message, :test) { nil }
@@ -25,10 +27,28 @@ describe Gitlab::Metrics::SidekiqMiddleware do
         with('TestWorker#perform').
         and_call_original
 
-      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).with(:sidekiq_queue_duration, instance_of(Float))
+      expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:set).
+        with(:sidekiq_queue_duration, instance_of(Float))
+
       expect_any_instance_of(Gitlab::Metrics::Transaction).to receive(:finish)
 
       middleware.call(worker, {}, :test) { nil }
     end
+
+    it 'tracks any raised exceptions' do
+      worker = double(:worker, class: double(:class, name: 'TestWorker'))
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:run).and_raise(RuntimeError)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:add_event).with(:sidekiq_exception)
+
+      expect_any_instance_of(Gitlab::Metrics::Transaction).
+        to receive(:finish)
+
+      expect { middleware.call(worker, message, :test) }.
+        to raise_error(RuntimeError)
+    end
   end
 end
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
diff --git a/spec/lib/gitlab/metrics_spec.rb b/spec/lib/gitlab/metrics_spec.rb
index 84f9475a0f8..ab6e311b1e8 100644
--- a/spec/lib/gitlab/metrics_spec.rb
+++ b/spec/lib/gitlab/metrics_spec.rb
@@ -153,4 +153,28 @@ describe Gitlab::Metrics do
       expect(described_class.series_prefix).to be_an_instance_of(String)
     end
   end
+
+  describe '.add_event' do
+    context 'without a transaction' do
+      it 'does nothing' do
+        expect_any_instance_of(Gitlab::Metrics::Transaction).
+          not_to receive(:add_event)
+
+        Gitlab::Metrics.add_event(:meow)
+      end
+    end
+
+    context 'with a transaction' do
+      it 'adds an event' do
+        transaction = Gitlab::Metrics::Transaction.new
+
+        expect(transaction).to receive(:add_event).with(:meow)
+
+        expect(Gitlab::Metrics).to receive(:current_transaction).
+          and_return(transaction)
+
+        Gitlab::Metrics.add_event(:meow)
+      end
+    end
+  end
 end