Add unix socket support

.travis.yml

@@ -8,6 +8,5 @@ rvm:
   - 2.2
   - 2.3
   - 2.4
-  - jruby-19mode
 
 bundler_args: --without=localdev

Rakefile

@@ -6,7 +6,8 @@ task :default => :spec
 
 Rake::TestTask.new(:spec) do |spec|
   spec.libs << 'lib' << 'spec'
-  spec.pattern = 'spec/**/*_spec.rb'
+  spec.loader = :direct
+  spec.pattern = './spec/statsd_spec.rb'
   spec.verbose = true
 end
 

lib/datadog/statsd.rb

@@ -61,6 +61,9 @@ class Statsd
     # StatsD port. Defaults to 8125.
     attr_reader :port
 
+    # DogStatsd unix socket path. Not used by default.
+    attr_reader :socket_path
+
     # Global tags to be added to every statsd call. Defaults to no tags.
     attr_reader :tags
 
@@ -90,8 +93,9 @@ def self.VERSION
     # @option opts [Array<String>] :tags tags to be added to every metric
     def initialize(host = DEFAULT_HOST, port = DEFAULT_PORT, opts = {}, max_buffer_size=50)
       self.host, self.port = host, port
+      @socket_path = opts[:socket_path]
       @prefix = nil
-      @socket = connect_to_socket(host, port)
+      @socket = connect_to_socket(host, port, socket_path) if @socket_path.nil?
       self.namespace = opts[:namespace]
       self.tags = opts[:tags]
       @buffer = Array.new
@@ -433,27 +437,45 @@ def send_stat(message)
       end
     end
 
-    def flush_buffer()
+    def flush_buffer
       send_to_socket(@buffer.join(NEW_LINE))
       @buffer = Array.new
     end
 
-    def connect_to_socket(host, port)
-      socket = UDPSocket.new
-      socket.connect(host, port)
+    def connect_to_socket(host, port, socket_path)
+      if !socket_path.nil?
+        socket = Socket.new(Socket::AF_UNIX, Socket::SOCK_DGRAM)
+        socket.connect(Socket.pack_sockaddr_un(socket_path))
+      else
+        socket = UDPSocket.new
+        socket.connect(host, port)
+      end
       socket
     end
 
+    def sock
+      @socket ||= connect_to_socket(host, port, socket_path)
+    end
+
     def send_to_socket(message)
       self.class.logger.debug { "Statsd: #{message}" } if self.class.logger
-      @socket.send(message, 0)
+      if @socket_path.nil?
+        sock.send(message, 0)
+      else
+        sock.sendmsg_nonblock(message)
+      end
     rescue => boom
+      if @socket_path && (boom.is_a?(Errno::ECONNREFUSED) ||
+                          boom.is_a?(Errno::ECONNRESET) ||
+                          boom.is_a?(Errno::ENOENT))
+        return @socket = nil
+      end
       # Try once to reconnect if the socket has been closed
       retries ||= 1
       if retries <= 1 && boom.is_a?(IOError) && boom.message =~ /closed stream/i
         retries += 1
         begin
-          @socket = connect_to_socket(host, port)
+          @socket = connect_to_socket(host, port, socket_path)
           retry
         rescue => e
           boom = e

spec/statsd_spec.rb

@@ -1,14 +1,15 @@
 require 'helper'
-require 'timecop'
+require 'socket'
 require 'stringio'
+require 'timecop'
 
 describe Datadog::Statsd do
   class Datadog::Statsd
     # we need to stub this
     attr_accessor :socket
   end
 
-  before do
+  before do |test|
     @statsd = Datadog::Statsd.new('localhost', 1234)
     @statsd.socket = FakeUDPSocket.new
   end
@@ -19,6 +20,22 @@ class Datadog::Statsd
       @statsd.port.must_equal 1234
     end
 
+    it "should create a UDPSocket when nothing is given" do
+      statsd = Datadog::Statsd.new
+      statsd.socket.must_be_instance_of(UDPSocket)
+    end
+
+    it "should create a UDPSocket when host and port are given" do
+      statsd = Datadog::Statsd.new('localhost', 1234)
+      statsd.socket.must_be_instance_of(UDPSocket)
+    end
+
+    it "should not create a socket when socket_path is given" do
+      # the socket may not exist when creating the Statsd object
+      statsd = Datadog::Statsd.new('localhost', 1234, {socket_path: '/tmp/socket'})
+      assert_nil statsd.socket
+    end
+
     it "should default the host to 127.0.0.1, port to 8125, namespace to nil, and tags to []" do
       statsd = Datadog::Statsd.new
       statsd.host.must_equal '127.0.0.1'
@@ -438,6 +455,112 @@ def send(*)
     end
   end
 
+  describe "UDS error handling" do
+    before do
+      @statsd = Datadog::Statsd.new('localhost', 1234, {:socket_path => '/tmp/socket'})
+      Datadog::Statsd.logger = Logger.new(@log = StringIO.new)
+    end
+
+    describe "when socket throws connection reset error" do
+      before do
+        @fake_socket = Minitest::Mock.new
+        @fake_socket.expect(:connect, true) { true }
+        @fake_socket.expect :sendmsg_nonblock, true, ['foo:1|c']
+        @fake_socket.expect(:sendmsg_nonblock, true) { raise Errno::ECONNRESET }
+
+        @fake_socket2 = Minitest::Mock.new
+        @fake_socket2.expect(:connect, true) { true }
+        @fake_socket2.expect :sendmsg_nonblock, true, ['bar:1|c']
+      end
+
+      it "should ignore message and try reconnect on next call" do
+        Socket.stub(:new, @fake_socket) do
+          @statsd.increment('foo')
+        end
+        @statsd.increment('baz')
+        Socket.stub(:new, @fake_socket2) do
+          @statsd.increment('bar')
+        end
+        @fake_socket.verify
+        @fake_socket2.verify
+      end
+    end
+
+    describe "when socket throws connection refused error" do
+      before do
+        @fake_socket = Minitest::Mock.new
+        @fake_socket.expect(:connect, true) { true }
+        @fake_socket.expect :sendmsg_nonblock, true, ['foo:1|c']
+        @fake_socket.expect(:sendmsg_nonblock, true) { raise Errno::ECONNREFUSED }
+
+        @fake_socket2 = Minitest::Mock.new
+        @fake_socket2.expect(:connect, true) { true }
+        @fake_socket2.expect :sendmsg_nonblock, true, ['bar:1|c']
+      end
+
+      it "should ignore message and try reconnect on next call" do
+        Socket.stub(:new, @fake_socket) do
+          @statsd.increment('foo')
+        end
+        @statsd.increment('baz')
+        Socket.stub(:new, @fake_socket2) do
+          @statsd.increment('bar')
+        end
+        @fake_socket.verify
+        @fake_socket2.verify
+      end
+    end
+
+    describe "when socket throws file not found error" do
+      before do
+        @fake_socket = Minitest::Mock.new
+        @fake_socket.expect(:connect, true) { true }
+        @fake_socket.expect :sendmsg_nonblock, true, ['foo:1|c']
+        @fake_socket.expect(:sendmsg_nonblock, true) { raise Errno::ENOENT }
+
+        @fake_socket2 = Minitest::Mock.new
+        @fake_socket2.expect(:connect, true) { true }
+        @fake_socket2.expect :sendmsg_nonblock, true, ['bar:1|c']
+      end
+
+      it "should ignore message and try reconnect on next call" do
+        Socket.stub(:new, @fake_socket) do
+          @statsd.increment('foo')
+        end
+        @statsd.increment('baz')
+        Socket.stub(:new, @fake_socket2) do
+          @statsd.increment('bar')
+        end
+        @fake_socket.verify
+        @fake_socket2.verify
+      end
+    end
+
+    describe "when socket is full" do
+      before do
+        @fake_socket = Minitest::Mock.new
+        @fake_socket.expect(:connect, true) { true }
+        @fake_socket.expect :sendmsg_nonblock, true, ['foo:1|c']
+        @fake_socket.expect(:sendmsg_nonblock, true) { raise IO::EAGAINWaitWritable }
+        @fake_socket.expect :sendmsg_nonblock, true, ['bar:1|c']
+
+        @fake_socket2 = Minitest::Mock.new
+      end
+
+      it "should ignore message but does not reconnect on next call" do
+        Socket.stub(:new, @fake_socket) do
+          @statsd.increment('foo')
+        end
+        @statsd.increment('baz')
+        Socket.stub(:new, @fake_socket2) do
+          @statsd.increment('bar')
+        end
+        @fake_socket.verify
+        @fake_socket2.verify
+      end
+    end
+  end
+
   describe "tagged" do
 
     it "gauges support tags" do