Prevent ENOBUFS errors by skipping UDP send buffer size configuration

The previous implementation attempted to set the UDP socket's send buffer
size, which could lead to ENOBUFS errors in some environments. This change:
- Overrides setup_socket in UDPConnection to skip buffer size configuration
- Improves socket creation by using the correct address family
- Updates error message to be more accurate ("Failed to setup socket")

This prevents potential buffer-related errors while maintaining the original
functionality for other connection types.

CHANGELOG.md

@@ -6,6 +6,10 @@ section below.
 
 ## Unreleased changes
 
+## Version 3.9.9
+
+- [#392](https://github.com/Shopify/statsd-instrument/pull/392) - Prevent ENOBUFS errors when using UDP, by skipping setting socket buffer size.
+
 ## Version 3.9.8
 
 - [#390](https://github.com/Shopify/statsd-instrument/pull/391) - Fixing bug in Environment when using UDS. The max packet size option was not being passed to the 

Gemfile

@@ -19,4 +19,9 @@ platform :mri do
   if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("3.2")
     gem "vernier", require: false
   end
+
+  # From Ruby >= 3.5, logger is not part of the stdlib anymore
+  if Gem::Version.new(RUBY_VERSION) >= Gem::Version.new("3.5")
+    gem "logger"
+  end
 end

lib/statsd/instrument/connection_behavior.rb

@@ -42,7 +42,7 @@ def setup_socket(original_socket)
         original_socket
       rescue IOError => e
         StatsD.logger.debug do
-          "[#{self.class.name}] Failed to create socket: #{e.class}: #{e.message}"
+          "[#{self.class.name}] Failed to setup socket: #{e.class}: #{e.message}"
         end
         nil
       end

lib/statsd/instrument/udp_connection.rb

@@ -25,11 +25,16 @@ def type
 
       private
 
+      def setup_socket(original_socket)
+        original_socket
+      end
+
       def socket
         @socket ||= begin
-          udp_socket = UDPSocket.new
+          family = Addrinfo.udp(host, port).afamily
+          udp_socket = UDPSocket.new(family)
           setup_socket(udp_socket)&.tap do |s|
-            s.connect(@host, @port)
+            s.connect(host, port)
           end
         end
       end

lib/statsd/instrument/version.rb

@@ -2,6 +2,6 @@
 
 module StatsD
   module Instrument
-    VERSION = "3.9.8"
+    VERSION = "3.9.9"
   end
 end

test/udp_sink_test.rb

@@ -151,25 +151,11 @@ def test_socket_error_should_invalidate_socket
       seq = sequence("connect_fail_connect_succeed")
 
       # First attempt
-      socket.expects(:setsockopt)
-        .with(Socket::SOL_SOCKET, Socket::SO_SNDBUF, StatsD::Instrument::UdpConnection::DEFAULT_MAX_PACKET_SIZE)
-        .in_sequence(seq)
-      socket.expects(:getsockopt)
-        .with(Socket::SOL_SOCKET, Socket::SO_SNDBUF)
-        .returns(mock(int: StatsD::Instrument::UdpConnection::DEFAULT_MAX_PACKET_SIZE))
-        .in_sequence(seq)
       socket.expects(:connect).with("localhost", 8125).in_sequence(seq)
       socket.expects(:send).raises(Errno::EDESTADDRREQ).in_sequence(seq)
       socket.expects(:close).in_sequence(seq)
 
       # Second attempt after error
-      socket.expects(:setsockopt)
-        .with(Socket::SOL_SOCKET, Socket::SO_SNDBUF, StatsD::Instrument::UdpConnection::DEFAULT_MAX_PACKET_SIZE)
-        .in_sequence(seq)
-      socket.expects(:getsockopt)
-        .with(Socket::SOL_SOCKET, Socket::SO_SNDBUF)
-        .returns(mock(int: StatsD::Instrument::UdpConnection::DEFAULT_MAX_PACKET_SIZE))
-        .in_sequence(seq)
       socket.expects(:connect).with("localhost", 8125).in_sequence(seq)
       socket.expects(:send).twice.returns(1).in_sequence(seq)
       socket.expects(:close).in_sequence(seq)