extract connection for separation of concerns

CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### Breaking changes
 
+ * port / host / socket_path readers are now on statsd.connection
  * port / host / tags / namespace can no longer be set on the instance to allow thread-safety [#87][] by [@grosser][] 
  * replace global logger with instance option [#90][] by [@grosser][] 
  * make format_service_check private [#89][] [@grosser][] 

lib/datadog/statsd.rb

@@ -16,12 +16,87 @@
 #   statsd = Datadog::Statsd.new 'localhost', 8125, :namespace => 'account'
 #   statsd.increment 'activate'
 # @example Create a statsd client with global tags
-#   statsd = Datadog::Statsd.new 'localhost', 8125, :tags => 'tag1:true'
+#   statsd = Datadog::Statsd.new 'localhost', 8125, tags: 'tag1:true'
 module Datadog
   class Statsd
 
-    DEFAULT_HOST = '127.0.0.1'
-    DEFAULT_PORT = 8125
+    class Connection
+      DEFAULT_HOST = '127.0.0.1'
+      DEFAULT_PORT = 8125
+
+      # StatsD host. Defaults to 127.0.0.1.
+      attr_reader :host
+
+      # StatsD port. Defaults to 8125.
+      attr_reader :port
+
+      # DogStatsd unix socket path. Not used by default.
+      attr_reader :socket_path
+
+      def initialize(host, port, socket_path, logger)
+        @host = host || DEFAULT_HOST
+        @port = port || DEFAULT_PORT
+        @socket_path = socket_path
+        @logger = logger
+      end
+
+      def write(message)
+        @logger.debug { "Statsd: #{message}" } if @logger
+        if @socket_path.nil?
+          socket.send(message, 0)
+        else
+          socket.sendmsg_nonblock(message)
+        end
+      rescue StandardError => boom
+        # Give up on this socket if it looks like it is bad
+        bad_socket = !@socket_path.nil? && (
+          boom.is_a?(Errno::ECONNREFUSED) ||
+          boom.is_a?(Errno::ECONNRESET) ||
+          boom.is_a?(Errno::ENOENT)
+        )
+        if bad_socket
+          @socket = nil
+          return
+        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
+            retry
+          rescue StandardError => e
+            boom = e
+          end
+        end
+
+        @logger.error { "Statsd: #{boom.class} #{boom}" } if @logger
+        nil
+      end
+
+      # Close the underlying socket
+      def close
+        @socket.close
+      end
+
+      private
+
+      def socket
+        @socket ||= connect
+      end
+
+      def connect
+        if @socket_path.nil?
+          socket = UDPSocket.new
+          socket.connect(@host, @port)
+        else
+          socket = Socket.new(Socket::AF_UNIX, Socket::SOCK_DGRAM)
+          socket.connect(Socket.pack_sockaddr_un(@socket_path))
+        end
+        socket
+      end
+    end
 
     # Create a dictionary to assign a key to every parameter's name, except for tags (treated differently)
     # Goal: Simple and fast to add some other parameters
@@ -60,15 +135,6 @@ class Statsd
     # A namespace to prepend to all statsd calls. Defaults to no namespace.
     attr_reader :namespace
 
-    # StatsD host. Defaults to 127.0.0.1.
-    attr_reader :host
-
-    # 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
 
@@ -78,8 +144,8 @@ class Statsd
     # Maximum buffer size in bytes before it is flushed
     attr_reader :max_buffer_bytes
 
-    # Logger
-    attr_reader :logger
+    # Connection
+    attr_reader :connection
 
     # @param [String] host your statsd host
     # @param [Integer] port your statsd port
@@ -89,18 +155,16 @@ class Statsd
     # @option [Integer] max_buffer_bytes max bytes to buffer when using #batch
     # @option [String] socket_path unix socket path
     def initialize(
-      host = DEFAULT_HOST,
-      port = DEFAULT_PORT,
+      host = nil,
+      port = nil,
       namespace: nil,
       tags: nil,
       max_buffer_bytes: 8192,
       socket_path: nil,
       logger: nil
     )
-      @host = host || DEFAULT_HOST
-      @port = port || DEFAULT_PORT
+      @connection = Connection.new(host, port, socket_path, logger)
       @logger = logger
-      @socket_path = socket_path
 
       @namespace = namespace
       @prefix = @namespace ? "#{@namespace}.".freeze : nil
@@ -308,7 +372,7 @@ def batch
 
     # Close the underlying socket
     def close
-      @socket.close
+      @connection.close
     end
 
     private
@@ -447,66 +511,15 @@ def send_stat(message)
         @buffer << message
         @buffer_bytes += message_bytes
       else
-        send_to_socket(message)
+        @connection.write(message)
       end
     end
 
     def flush_buffer
       return if @buffer_bytes == 0
-      send_to_socket(@buffer)
+      @connection.write(@buffer)
       @buffer = String.new
       @buffer_bytes = 0
     end
-
-    def connect_to_socket
-      if @socket_path.nil?
-        socket = UDPSocket.new
-        socket.connect(@host, @port)
-      else
-        socket = Socket.new(Socket::AF_UNIX, Socket::SOCK_DGRAM)
-        socket.connect(Socket.pack_sockaddr_un(@socket_path))
-      end
-      socket
-    end
-
-    # TODO: rename to `socket` which breaks a lot of tests
-    def sock
-      @socket ||= connect_to_socket
-    end
-
-    def send_to_socket(message)
-      @logger.debug { "Statsd: #{message}" } if @logger
-      if @socket_path.nil?
-        sock.send(message, 0)
-      else
-        sock.sendmsg_nonblock(message)
-      end
-    rescue StandardError => boom
-      # Give up on this socket if it looks like it is bad
-      bad_socket = !@socket_path.nil? && (
-        boom.is_a?(Errno::ECONNREFUSED) ||
-        boom.is_a?(Errno::ECONNRESET) ||
-        boom.is_a?(Errno::ENOENT)
-      )
-      if bad_socket
-        @socket = nil
-        return
-      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
-          retry
-        rescue StandardError => e
-          boom = e
-        end
-      end
-
-      @logger.error { "Statsd: #{boom.class} #{boom}" } if @logger
-      nil
-    end
   end
 end