1 files changed, 191 insertions, 0 deletions
diff --git a/spec/lib/gitlab/prometheus_client_spec.rb b/spec/lib/gitlab/prometheus_client_spec.rb
new file mode 100644
index 00000000000..2d8bd2f6b97
--- /dev/null
+++ b/spec/lib/gitlab/prometheus_client_spec.rb
@@ -0,0 +1,191 @@
+require 'spec_helper'
+
+describe Gitlab::PrometheusClient, lib: true do
+  include PrometheusHelpers
+
+  subject { described_class.new(api_url: 'https://prometheus.example.com') }
+
+  describe '#ping' do
+    it 'issues a "query" request to the API endpoint' do
+      req_stub = stub_prometheus_request(prometheus_query_url('1'), body: prometheus_value_body('vector'))
+
+      expect(subject.ping).to eq({ "resultType" => "vector", "result" => [{ "metric" => {}, "value" => [1488772511.004, "0.000041021495238095323"] }] })
+      expect(req_stub).to have_been_requested
+    end
+  end
+
+  # This shared examples expect:
+  # - query_url: A query URL
+  # - execute_query: A query call
+  shared_examples 'failure response' do
+    context 'when request returns 400 with an error message' do
+      it 'raises a Gitlab::PrometheusError error' do
+        req_stub = stub_prometheus_request(query_url, status: 400, body: { error: 'bar!' })
+
+        expect { execute_query }
+          .to raise_error(Gitlab::PrometheusError, 'bar!')
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns 400 without an error message' do
+      it 'raises a Gitlab::PrometheusError error' do
+        req_stub = stub_prometheus_request(query_url, status: 400)
+
+        expect { execute_query }
+          .to raise_error(Gitlab::PrometheusError, 'Bad data received')
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns 500' do
+      it 'raises a Gitlab::PrometheusError error' do
+        req_stub = stub_prometheus_request(query_url, status: 500, body: { message: 'FAIL!' })
+
+        expect { execute_query }
+          .to raise_error(Gitlab::PrometheusError, '500 - {"message":"FAIL!"}')
+        expect(req_stub).to have_been_requested
+      end
+    end
+  end
+
+  describe 'failure to reach a provided prometheus url' do
+    let(:prometheus_url) {"https://prometheus.invalid.example.com"}
+
+    context 'exceptions are raised' do
+      it 'raises a Gitlab::PrometheusError error when a SocketError is rescued' do
+        req_stub = stub_prometheus_request_with_exception(prometheus_url, SocketError)
+
+        expect { subject.send(:get, prometheus_url) }
+          .to raise_error(Gitlab::PrometheusError, "Can't connect to #{prometheus_url}")
+        expect(req_stub).to have_been_requested
+      end
+
+      it 'raises a Gitlab::PrometheusError error when a SSLError is rescued' do
+        req_stub = stub_prometheus_request_with_exception(prometheus_url, OpenSSL::SSL::SSLError)
+
+        expect { subject.send(:get, prometheus_url) }
+          .to raise_error(Gitlab::PrometheusError, "#{prometheus_url} contains invalid SSL data")
+        expect(req_stub).to have_been_requested
+      end
+
+      it 'raises a Gitlab::PrometheusError error when a HTTParty::Error is rescued' do
+        req_stub = stub_prometheus_request_with_exception(prometheus_url, HTTParty::Error)
+
+        expect { subject.send(:get, prometheus_url) }
+          .to raise_error(Gitlab::PrometheusError, "Network connection error")
+        expect(req_stub).to have_been_requested
+      end
+    end
+  end
+
+  describe '#query' do
+    let(:prometheus_query) { prometheus_cpu_query('env-slug') }
+    let(:query_url) { prometheus_query_with_time_url(prometheus_query, Time.now.utc) }
+
+    around do |example|
+      Timecop.freeze { example.run }
+    end
+
+    context 'when request returns vector results' do
+      it 'returns data from the API call' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_value_body('vector'))
+
+        expect(subject.query(prometheus_query)).to eq [{ "metric" => {}, "value" => [1488772511.004, "0.000041021495238095323"] }]
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns matrix results' do
+      it 'returns nil' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_value_body('matrix'))
+
+        expect(subject.query(prometheus_query)).to be_nil
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns no data' do
+      it 'returns []' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_empty_body('vector'))
+
+        expect(subject.query(prometheus_query)).to be_empty
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    it_behaves_like 'failure response' do
+      let(:execute_query) { subject.query(prometheus_query) }
+    end
+  end
+
+  describe '#query_range' do
+    let(:prometheus_query) { prometheus_memory_query('env-slug') }
+    let(:query_url) { prometheus_query_range_url(prometheus_query) }
+
+    around do |example|
+      Timecop.freeze { example.run }
+    end
+
+    context 'when non utc time is passed' do
+      let(:time_stop) { Time.now.in_time_zone("Warsaw") }
+      let(:time_start) { time_stop - 8.hours }
+
+      let(:query_url) { prometheus_query_range_url(prometheus_query, start: time_start.utc.to_f, stop: time_stop.utc.to_f) }
+
+      it 'passed dates are properly converted to utc' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_values_body('vector'))
+
+        subject.query_range(prometheus_query, start: time_start, stop: time_stop)
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when a start time is passed' do
+      let(:query_url) { prometheus_query_range_url(prometheus_query, start: 2.hours.ago) }
+
+      it 'passed it in the requested URL' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_values_body('vector'))
+
+        subject.query_range(prometheus_query, start: 2.hours.ago)
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns vector results' do
+      it 'returns nil' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_values_body('vector'))
+
+        expect(subject.query_range(prometheus_query)).to be_nil
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns matrix results' do
+      it 'returns data from the API call' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_values_body('matrix'))
+
+        expect(subject.query_range(prometheus_query)).to eq([
+          {
+            "metric" => {},
+            "values" => [[1488758662.506, "0.00002996364761904785"], [1488758722.506, "0.00003090239047619091"]]
+          }
+        ])
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    context 'when request returns no data' do
+      it 'returns []' do
+        req_stub = stub_prometheus_request(query_url, body: prometheus_empty_body('matrix'))
+
+        expect(subject.query_range(prometheus_query)).to be_empty
+        expect(req_stub).to have_been_requested
+      end
+    end
+
+    it_behaves_like 'failure response' do
+      let(:execute_query) { subject.query_range(prometheus_query) }
+    end
+  end
+end