feat: I/O timeouts (#1025)

Author: nickamorim

lib/dalli/socket.rb

@@ -117,19 +117,33 @@ def self.create_socket_with_timeout(host, port, options)
       end
 
       def self.init_socket_options(sock, options)
+        configure_tcp_options(sock, options)
+        configure_socket_buffers(sock, options)
+        configure_timeout(sock, options)
+      end
+
+      def self.configure_tcp_options(sock, options)
         sock.setsockopt(::Socket::IPPROTO_TCP, ::Socket::TCP_NODELAY, true)
         sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_KEEPALIVE, true) if options[:keepalive]
+      end
+
+      def self.configure_socket_buffers(sock, options)
         sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_RCVBUF, options[:rcvbuf]) if options[:rcvbuf]
         sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_SNDBUF, options[:sndbuf]) if options[:sndbuf]
+      end
 
+      def self.configure_timeout(sock, options)
         return unless options[:socket_timeout]
 
-        seconds, fractional = options[:socket_timeout].divmod(1)
-        microseconds = fractional * 1_000_000
-        timeval = [seconds, microseconds].pack('l_2')
+        if sock.respond_to?(:timeout=)
+          sock.timeout = options[:socket_timeout]
+        else
+          seconds, fractional = options[:socket_timeout].divmod(1)
+          timeval = [seconds, fractional * 1_000_000].pack('l_2')
 
-        sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_RCVTIMEO, timeval)
-        sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_SNDTIMEO, timeval)
+          sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_RCVTIMEO, timeval)
+          sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_SNDTIMEO, timeval)
+        end
       end
 
       def self.wrapping_ssl_socket(tcp_socket, host, ssl_context)
@@ -168,9 +182,16 @@ def self.open(path, options = {})
           Timeout.timeout(options[:socket_timeout]) do
             sock = new(path)
             sock.options = { path: path }.merge(options)
+            init_socket_options(sock, options)
             sock
           end
         end
+
+        def self.init_socket_options(sock, options)
+          # https://man7.org/linux/man-pages/man7/unix.7.html
+          sock.setsockopt(::Socket::SOL_SOCKET, ::Socket::SO_SNDBUF, options[:sndbuf]) if options[:sndbuf]
+          sock.timeout = options[:socket_timeout] if options[:socket_timeout] && sock.respond_to?(:timeout=)
+        end
       end
     end
   end

test/integration/test_network.rb

@@ -74,6 +74,24 @@
           end
         end
 
+        it 'handles operation timeouts' do
+          next if p == :binary
+
+          memcached_mock(lambda { |sock|
+            # handle initial version call
+            sock.gets
+            sock.write("VERSION 1.6.0\r\n")
+
+            sleep(0.3)
+          }) do
+            dc = Dalli::Client.new('localhost:19123', socket_timeout: 0.1, protocol: p, socket_max_failures: 0,
+                                                      socket_failure_delay: 0.0, down_retry_delay: 0.0)
+            assert_raises Dalli::RingError, message: 'No server available' do
+              dc.get('abc')
+            end
+          end
+        end
+
         it 'opens a standard TCP connection when ssl_context is not configured' do
           memcached_persistent(p) do |dc|
             server = dc.send(:ring).servers.first