1 files changed, 123 insertions, 0 deletions
diff --git a/spec/lib/gitlab/metrics/samplers/puma_sampler_spec.rb b/spec/lib/gitlab/metrics/samplers/puma_sampler_spec.rb
new file mode 100644
index 00000000000..f4a6e1fc7d9
--- /dev/null
+++ b/spec/lib/gitlab/metrics/samplers/puma_sampler_spec.rb
@@ -0,0 +1,123 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe Gitlab::Metrics::Samplers::PumaSampler do
+  subject { described_class.new(5) }
+  let(:null_metric) { double('null_metric', set: nil, observe: nil) }
+
+  before do
+    allow(Gitlab::Metrics::NullMetric).to receive(:instance).and_return(null_metric)
+  end
+
+  describe '#sample' do
+    before do
+      expect(subject).to receive(:puma_stats).and_return(puma_stats)
+    end
+
+    context 'in cluster mode' do
+      let(:puma_stats) do
+        <<~EOS
+        {
+          "workers": 2,
+          "phase": 2,
+          "booted_workers": 2,
+          "old_workers": 0,
+          "worker_status": [{
+            "pid": 32534,
+            "index": 0,
+            "phase": 1,
+            "booted": true,
+            "last_checkin": "2019-05-15T07:57:55Z",
+            "last_status": {
+              "backlog":0,
+              "running":1,
+              "pool_capacity":4,
+              "max_threads": 4
+            }
+          }]
+        }
+        EOS
+      end
+
+      it 'samples master statistics' do
+        labels = { worker: 'master' }
+
+        expect(subject.metrics[:puma_workers]).to receive(:set).with(labels, 2)
+        expect(subject.metrics[:puma_running_workers]).to receive(:set).with(labels, 2)
+        expect(subject.metrics[:puma_stale_workers]).to receive(:set).with(labels, 0)
+        expect(subject.metrics[:puma_phase]).to receive(:set).once.with(labels, 2)
+        expect(subject.metrics[:puma_phase]).to receive(:set).once.with({ worker: 'worker_0' }, 1)
+
+        subject.sample
+      end
+
+      it 'samples worker statistics' do
+        labels = { worker: 'worker_0' }
+
+        expect_worker_stats(labels)
+
+        subject.sample
+      end
+    end
+
+    context 'with empty worker stats' do
+      let(:puma_stats) do
+        <<~EOS
+        {
+          "workers": 2,
+          "phase": 2,
+          "booted_workers": 2,
+          "old_workers": 0,
+          "worker_status": [{
+            "pid": 32534,
+            "index": 0,
+            "phase": 1,
+            "booted": true,
+            "last_checkin": "2019-05-15T07:57:55Z",
+            "last_status": {}
+          }]
+        }
+        EOS
+      end
+
+      it 'does not log worker stats' do
+        expect(subject).not_to receive(:set_worker_metrics)
+
+        subject.sample
+      end
+    end
+
+    context 'in single mode' do
+      let(:puma_stats) do
+        <<~EOS
+        {
+          "backlog":0,
+          "running":1,
+          "pool_capacity":4,
+          "max_threads": 4
+        }
+        EOS
+      end
+
+      it 'samples worker statistics' do
+        labels = {}
+
+        expect(subject.metrics[:puma_workers]).to receive(:set).with(labels, 1)
+        expect(subject.metrics[:puma_running_workers]).to receive(:set).with(labels, 1)
+        expect_worker_stats(labels)
+
+        subject.sample
+      end
+    end
+  end
+
+  def expect_worker_stats(labels)
+    expect(subject.metrics[:puma_queued_connections]).to receive(:set).with(labels, 0)
+    expect(subject.metrics[:puma_active_connections]).to receive(:set).with(labels, 0)
+    expect(subject.metrics[:puma_running]).to receive(:set).with(labels, 1)
+    expect(subject.metrics[:puma_pool_capacity]).to receive(:set).with(labels, 4)
+    expect(subject.metrics[:puma_max_threads]).to receive(:set).with(labels, 4)
+    expect(subject.metrics[:puma_idle_threads]).to receive(:set).with(labels, 1)
+  end
+end