Instrument Unicorn with Ruby exporter

3 files changed, 201 insertions, 5 deletions

diff --git a/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb b/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb
new file mode 100644
index 00000000000..94251af305f
--- /dev/null
+++ b/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb
@@ -0,0 +1,88 @@
+require 'spec_helper'
+
+describe Gitlab::Metrics::ConnectionRackMiddleware do
+  let(:app) { double('app') }
+  subject { described_class.new(app) }
+
+  around do |example|
+    Timecop.freeze { example.run }
+  end
+
+  describe '#call' do
+    let(:status) { 100 }
+    let(:env) { { 'REQUEST_METHOD' => 'GET' } }
+    let(:stack_result) { [status, {}, 'body'] }
+
+    before do
+      allow(app).to receive(:call).and_return(stack_result)
+    end
+
+    context '@app.call succeeds with 200' do
+      before do
+        allow(app).to receive(:call).and_return([200, nil, nil])
+      end
+
+      it 'increments response count with status label' do
+        expect(described_class).to receive_message_chain(:rack_response_count, :increment).with(include(status: 200, method: 'get'))
+
+        subject.call(env)
+      end
+
+      it 'increments requests count' do
+        expect(described_class).to receive_message_chain(:rack_request_count, :increment).with(method: 'get')
+
+        subject.call(env)
+      end
+
+      it 'measures execution time' do
+        execution_time = 10
+        allow(app).to receive(:call) do |*args|
+          Timecop.freeze(execution_time.seconds)
+        end
+
+        expect(described_class).to receive_message_chain(:rack_execution_time, :observe).with({}, execution_time)
+
+        subject.call(env)
+      end
+    end
+
+    context '@app.call throws exception' do
+      let(:rack_response_count) { double('rack_response_count') }
+
+      before do
+        allow(app).to receive(:call).and_raise(StandardError)
+        allow(described_class).to receive(:rack_response_count).and_return(rack_response_count)
+      end
+
+      it 'increments exceptions count' do
+        expect(described_class).to receive_message_chain(:rack_uncaught_errors_count, :increment)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it 'increments requests count' do
+        expect(described_class).to receive_message_chain(:rack_request_count, :increment).with(method: 'get')
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it "does't increment response count" do
+        expect(described_class.rack_response_count).not_to receive(:increment)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it 'measures execution time' do
+        execution_time = 10
+        allow(app).to receive(:call) do |*args|
+          Timecop.freeze(execution_time.seconds)
+          raise StandardError
+        end
+
+        expect(described_class).to receive_message_chain(:rack_execution_time, :observe).with({}, execution_time)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+    end
+  end
+end
diff --git a/spec/lib/gitlab/metrics/sampler_spec.rb b/spec/lib/gitlab/metrics/influx_sampler_spec.rb
index d07ce6f81af..0bc68d64276 100644
--- a/spec/lib/gitlab/metrics/sampler_spec.rb
+++ b/spec/lib/gitlab/metrics/influx_sampler_spec.rb
@@ -1,6 +1,6 @@
 require 'spec_helper'
 
-describe Gitlab::Metrics::Sampler do
+describe Gitlab::Metrics::InfluxSampler do
   let(:sampler) { described_class.new(5) }
 
   after do
@@ -8,10 +8,10 @@ describe Gitlab::Metrics::Sampler do
   end
 
   describe '#start' do
-    it 'gathers a sample at a given interval' do
-      expect(sampler).to receive(:sleep).with(a_kind_of(Numeric))
-      expect(sampler).to receive(:sample)
-      expect(sampler).to receive(:loop).and_yield
+    it 'runs once and gathers a sample at a given interval' do
+      expect(sampler).to receive(:sleep).with(a_kind_of(Numeric)).twice
+      expect(sampler).to receive(:sample).once
+      expect(sampler).to receive(:running).and_return(false, true, false)
 
       sampler.start.join
     end
diff --git a/spec/lib/gitlab/metrics/unicorn_sampler_spec.rb b/spec/lib/gitlab/metrics/unicorn_sampler_spec.rb
new file mode 100644
index 00000000000..dc0d1f2e940
--- /dev/null
+++ b/spec/lib/gitlab/metrics/unicorn_sampler_spec.rb
@@ -0,0 +1,108 @@
+require 'spec_helper'
+
+describe Gitlab::Metrics::UnicornSampler do
+  subject { described_class.new(1.second) }
+
+  describe '#sample' do
+    let(:unicorn) { double('unicorn') }
+    let(:raindrops) { double('raindrops') }
+    let(:stats) { double('stats') }
+
+    before do
+      stub_const('Unicorn', unicorn)
+      stub_const('Raindrops::Linux', raindrops)
+      allow(raindrops).to receive(:unix_listener_stats).and_return({})
+      allow(raindrops).to receive(:tcp_listener_stats).and_return({})
+    end
+
+    context 'unicorn listens on unix sockets' do
+      let(:socket_address) { '/some/sock' }
+      let(:sockets) { [socket_address] }
+
+      before do
+        allow(unicorn).to receive(:listener_names).and_return(sockets)
+      end
+
+      it 'samples socket data' do
+        expect(raindrops).to receive(:unix_listener_stats).with(sockets)
+
+        subject.sample
+      end
+
+      context 'stats collected' do
+        before do
+          allow(stats).to receive(:active).and_return('active')
+          allow(stats).to receive(:queued).and_return('queued')
+          allow(raindrops).to receive(:unix_listener_stats).and_return({ socket_address => stats })
+        end
+
+        it 'updates metrics type unix and with addr' do
+          labels = { type: 'unix', address: socket_address }
+
+          expect(subject).to receive_message_chain(:unicorn_active_connections, :set).with(labels, 'active')
+          expect(subject).to receive_message_chain(:unicorn_queued_connections, :set).with(labels, 'queued')
+
+          subject.sample
+        end
+      end
+    end
+
+    context 'unicorn listens on tcp sockets' do
+      let(:tcp_socket_address) { '0.0.0.0:8080' }
+      let(:tcp_sockets) { [tcp_socket_address] }
+
+      before do
+        allow(unicorn).to receive(:listener_names).and_return(tcp_sockets)
+      end
+
+      it 'samples socket data' do
+        expect(raindrops).to receive(:tcp_listener_stats).with(tcp_sockets)
+
+        subject.sample
+      end
+
+      context 'stats collected' do
+        before do
+          allow(stats).to receive(:active).and_return('active')
+          allow(stats).to receive(:queued).and_return('queued')
+          allow(raindrops).to receive(:tcp_listener_stats).and_return({ tcp_socket_address => stats })
+        end
+
+        it 'updates metrics type unix and with addr' do
+          labels = { type: 'tcp', address: tcp_socket_address }
+
+          expect(subject).to receive_message_chain(:unicorn_active_connections, :set).with(labels, 'active')
+          expect(subject).to receive_message_chain(:unicorn_queued_connections, :set).with(labels, 'queued')
+
+          subject.sample
+        end
+      end
+    end
+  end
+
+  describe '#start' do
+    context 'when enabled' do
+      before do
+        allow(subject).to receive(:enabled?).and_return(true)
+      end
+
+      it 'creates new thread' do
+        expect(Thread).to receive(:new)
+
+        subject.start
+      end
+    end
+
+    context 'when disabled' do
+      before do
+        allow(subject).to receive(:enabled?).and_return(false)
+      end
+
+      it "doesn't create new thread" do
+        expect(Thread).not_to receive(:new)
+
+        subject.start
+      end
+    end
+  end
+end