feat: support uds in datadog statsd

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## Unreleased
 
+* Add unix domain socket support for Datadog StatsD metrics
 * Bump minimum rdkafka gem version to 0.15.0
 * Bump minimum Ruby version to 3.0
 

README.md

@@ -414,6 +414,7 @@ Racecar supports [Datadog](https://www.datadoghq.com/) monitoring integration. I
 - `datadog_enabled` – Whether Datadog monitoring is enabled (defaults to `false`).
 - `datadog_host` – The host running the Datadog agent.
 - `datadog_port` – The port of the Datadog agent.
+- `datadog_socket_path` – The unix domain socket of the Datadog agent (when set takes precedence over host/port).
 - `datadog_namespace` – The namespace to use for Datadog metrics.
 - `datadog_tags` – Tags that should always be set on Datadog metrics.
 
@@ -695,7 +696,7 @@ In order to safely upgrade from Racecar v1 to v2, you need to completely shut do
 
 Racecar v2 requires a C library (zlib) to compress the messages before producing to the topic. If not already installed on you consumer docker container, please install using following command in Dockerfile of consumer
 
-``` 
+```
 apt-get update && apt-get install -y libzstd-dev
 ```
 

lib/racecar/cli.rb

@@ -157,10 +157,11 @@ def configure_datadog
       require_relative './datadog'
 
       Datadog.configure do |datadog|
-        datadog.host      = config.datadog_host unless config.datadog_host.nil?
-        datadog.port      = config.datadog_port unless config.datadog_port.nil?
-        datadog.namespace = config.datadog_namespace unless config.datadog_namespace.nil?
-        datadog.tags      = config.datadog_tags unless config.datadog_tags.nil?
+        datadog.host        = config.datadog_host unless config.datadog_host.nil?
+        datadog.port        = config.datadog_port unless config.datadog_port.nil?
+        datadog.socket_path = config.socket_path unless config.socket_path.nil?
+        datadog.namespace   = config.datadog_namespace unless config.datadog_namespace.nil?
+        datadog.tags        = config.datadog_tags unless config.datadog_tags.nil?
       end
     end
   end

lib/racecar/config.rb

@@ -158,6 +158,9 @@ class Config < KingKonf::Config
     desc "The port of the Datadog agent"
     integer :datadog_port
 
+    desc "The unix domain socket of the Datadog agent (when set takes precedence over host/port)"
+    integer :datadog_socket_path
+
     desc "The namespace to use for Datadog metrics"
     string :datadog_namespace
 

lib/racecar/datadog.rb

@@ -19,7 +19,11 @@ def configure
       end
 
       def statsd
-        @statsd ||= ::Datadog::Statsd.new(host, port, namespace: namespace, tags: tags)
+        @statsd ||= if socket_path
+          ::Datadog::Statsd.new(socket_path: socket_path, namespace: namespace, tags: tags)
+        else
+          ::Datadog::Statsd.new(host, port, namespace: namespace, tags: tags)
+        end
       end
 
       def statsd=(statsd)
@@ -45,6 +49,15 @@ def port=(port)
         clear
       end
 
+      def socket_path
+        @socket_path
+      end
+
+      def socket_path=(socket_path)
+        @socket_path = socket_path
+        clear
+      end
+
       def namespace
         @namespace ||= STATSD_NAMESPACE
       end

spec/datadog_spec.rb

@@ -1,6 +1,35 @@
 # frozen_string_literal: true
 
 require "racecar/datadog"
+
+RSpec.describe Racecar::Datadog do
+  describe '.statsd' do
+    it 'configures with host/port by default' do
+      statsd = Racecar::Datadog.statsd
+      expect(statsd.host).to eq('127.0.0.1')
+      expect(statsd.port).to eq(8125)
+      expect(statsd.socket_path).to be_nil
+    end
+
+    it 'configures with host/port explicitly' do
+      Racecar::Datadog.host = '10.0.0.1'
+      Racecar::Datadog.port = 8555
+      statsd = Racecar::Datadog.statsd
+      expect(statsd.host).to eq('10.0.0.1')
+      expect(statsd.port).to eq(8555)
+      expect(statsd.socket_path).to be_nil
+    end
+
+    it 'configures with socket_path explicitly' do
+      Racecar::Datadog.socket_path = '/var/run/datadog/dsd.socket'
+      statsd = Racecar::Datadog.statsd
+      expect(statsd.socket_path).to eq('/var/run/datadog/dsd.socket')
+      expect(statsd.host).to be_nil
+      expect(statsd.port).to be_nil
+    end
+  end
+end
+
 RSpec.describe Racecar::Datadog::StatsdSubscriber do
   describe '#emit' do
     let(:subscriber)  { Racecar::Datadog::StatsdSubscriber.new }