Merge pull request #248 from jordan-brough/distribution-time

Add a "distribution_time" method

lib/datadog/statsd.rb

@@ -237,6 +237,26 @@ def distribution(stat, value, opts = EMPTY_OPTIONS)
  send_stats(stat, value, DISTRIBUTION_TYPE, opts)
  end
 
+ # Reports execution time of the provided block as a distribution.
+ #
+ # If the block fails, the stat is still reported, then the error
+ # is reraised
+ #
+ # @param [String] stat stat name.
+ # @param [Numeric] value distribution value.
+ # @param [Hash] opts the options to create the metric with
+ # @option opts [Numeric] :sample_rate sample rate, 1 for always
+ # @option opts [Array<String>] :tags An array of tags
+ # @example Report the time (in ms) taken to activate an account
+ # $statsd.distribution_time('account.activate') { @account.activate! }
+ def distribution_time(stat, opts = EMPTY_OPTIONS)
+ opts = { sample_rate: opts } if opts.is_a?(Numeric)
+ start = now
+ yield
+ ensure
+ distribution(stat, ((now - start) * 1000).round, opts)
+ end
+
  # Sends a timing (in ms) for the given stat to the statsd server. The
  # sample_rate determines what percentage of the time this report is sent. The
  # statsd server then uses the sample_rate to correctly track the average

spec/statsd_spec.rb

@@ -799,6 +799,134 @@
  end
  end
 
+ describe '#distribution_time' do
+ let(:namespace) { nil }
+ let(:sample_rate) { nil }
+ let(:tags) { nil }
+
+ let(:before_date) do
+ DateTime.new(2020, 2, 25, 12, 12, 12)
+ end
+
+ let(:after_date) do
+ DateTime.new(2020, 2, 25, 12, 12, 13)
+ end
+
+ before do
+ Timecop.freeze(before_date)
+ allow(Process).to receive(:clock_gettime).and_return(0)
+ end
+
+ it_behaves_like 'a metrics method', 'foobar:1000|d' do
+ let(:basic_action) do
+ subject.distribution_time('foobar', tags: action_tags) do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ end
+
+ subject.flush(sync: true)
+ end
+ end
+
+ context 'when actually testing time' do
+ it 'sends the timing' do
+ subject.distribution_time('foobar') do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ end
+
+ subject.flush(sync: true)
+
+ expect(socket.recv[0]).to eq_with_telemetry 'foobar:1000|d'
+ end
+
+ it 'ensures the timing is sent' do
+ # rubocop:disable Lint/RescueWithoutErrorClass
+ subject.distribution_time('foobar') do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ raise 'stop'
+ end rescue nil
+ # rubocop:enable Lint/RescueWithoutErrorClass
+
+ subject.flush(sync: true)
+
+ expect(socket.recv[0]).to eq_with_telemetry 'foobar:1000|d'
+ end
+ end
+
+ it 'returns the result of the block' do
+ expect(subject.distribution_time('foobar') { 'test' }).to eq 'test'
+ end
+
+ it 'does not catch errors if block is failing' do
+ expect do
+ subject.distribution_time('foobar') do
+ raise 'yolo'
+ end
+ end.to raise_error(StandardError, 'yolo')
+ end
+
+ it 'can run without "PROCESS_TIME_SUPPORTED"' do
+ stub_const('PROCESS_TIME_SUPPORTED', false)
+
+ expect do
+ subject.distribution_time('foobar') {}
+ end.not_to raise_error
+ end
+
+ context 'with a sample rate' do
+ before do
+ allow(subject).to receive(:rand).and_return(0)
+ end
+
+ it 'sends the timing with the sample rate' do
+ subject.distribution_time('foobar', sample_rate: 0.5) do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ end
+
+ subject.flush(sync: true)
+
+ expect(socket.recv[0]).to eq_with_telemetry 'foobar:1000|d|@0.5'
+ end
+ end
+
+ context 'with a sample rate like statsd-ruby' do
+ before do
+ allow(subject).to receive(:rand).and_return(0)
+ end
+
+ it 'sends the timing with the sample rate' do
+ subject.distribution_time('foobar', 0.5) do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ end
+
+ subject.flush(sync: true)
+
+ expect(socket.recv[0]).to eq_with_telemetry 'foobar:1000|d|@0.5'
+ end
+ end
+
+ context 'with pre sampling' do
+ before do
+ allow(subject).to receive(:rand).and_return(1)
+ end
+
+ it 'sends the sample rate without additional sampling' do
+ subject.distribution_time('foobar', sample_rate: 0.5, pre_sampled: true) do
+ Timecop.travel(after_date)
+ allow(Process).to receive(:clock_gettime).and_return(1)
+ end
+
+ subject.flush(sync: true)
+
+ expect(socket.recv[0]).to eq_with_telemetry 'foobar:1000|d|@0.5'
+ end
+ end
+ end
+
  describe '#distribution' do
  let(:namespace) { nil }
  let(:sample_rate) { nil }