Test the Datadog reporter

Author: dasch

lib/kafka/datadog.rb

@@ -31,11 +31,11 @@ def self.statsd
       @statsd ||= Statsd.new(Statsd::DEFAULT_HOST, Statsd::DEFAULT_HOST, namespace: STATSD_NAMESPACE)
     end
 
-    def self.statsd_host=(host)
+    def self.host=(host)
       statsd.host = host
     end
 
-    def self.statsd_port=(port)
+    def self.port=(port)
       statsd.port = port
     end
 

spec/fake_datadog_agent.rb

@@ -0,0 +1,35 @@
+require "socket"
+
+class FakeDatadogAgent
+  attr_reader :host, :port, :metrics
+
+  def initialize
+    @host = "127.0.0.1"
+    @port = 9999
+    @socket = UDPSocket.new
+    @thread = nil
+    @metrics = []
+
+    @socket.bind(@host, @port)
+  end
+
+  def start
+    @thread = Thread.new { loop { receive } }
+    @thread.abort_on_exception = true
+  end
+
+  def wait_for_metrics
+    sleep 0.1 until @metrics.count > 0
+  end
+
+  private
+
+  def receive
+    data, sender = @socket.recvfrom(512)
+
+    data.split("\n").each do |message|
+      metric = message.split(":").first
+      @metrics << metric if metric
+    end
+  end
+end

spec/functional/datadog_spec.rb

@@ -0,0 +1,22 @@
+require "kafka/datadog"
+require "socket"
+require "fake_datadog_agent"
+
+describe "Reporting metrics to Datadog", functional: true do
+  example "reporting connection metrics" do
+    agent = FakeDatadogAgent.new
+
+    Kafka::Datadog.port = agent.port
+
+    agent.start
+
+    kafka.topics
+
+    agent.wait_for_metrics
+
+    expect(agent.metrics).to include("ruby_kafka.api.calls")
+    expect(agent.metrics).to include("ruby_kafka.api.latency")
+    expect(agent.metrics).to include("ruby_kafka.api.request_size")
+    expect(agent.metrics).to include("ruby_kafka.api.response_size")
+  end
+end