UDS support for R2 HTTP client

Author: Abhishek Bharadwaj

Diff for: CHANGELOG.md

@@ -14,6 +14,9 @@ and what APIs have changed, if applicable.
 
 ## [Unreleased]
 
+## [29.38.5-rc.1] - 2022-09-13
+- Add Support for UDS transport protocol in R2 outbound traffic over HTTP1.1
+
 ## [29.38.4] - 2022-09-08
 - Use ZooKeeper 3.6.3
 

Diff for: r2-netty/src/main/java/com/linkedin/r2/netty/client/http/HttpChannelInitializer.java

@@ -25,6 +25,7 @@
 import com.linkedin.r2.netty.handler.common.SslHandshakeTimingHandler;
 import com.linkedin.r2.netty.handler.http.HttpMessageDecoders;
 import com.linkedin.r2.netty.handler.http.HttpMessageEncoders;
+import io.netty.channel.Channel;
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import io.netty.handler.codec.http.HttpClientCodec;
@@ -60,7 +61,7 @@
  * @author Sean Sheng
  * @author Nizar Mankulangara
  */
-class HttpChannelInitializer extends ChannelInitializer<NioSocketChannel>
+class HttpChannelInitializer extends ChannelInitializer<Channel>
 {
   /**
    * HTTP/2 stream channels are not recyclable and should be disposed upon completion.
@@ -93,7 +94,7 @@ class HttpChannelInitializer extends ChannelInitializer<NioSocketChannel>
   }
 
   @Override
-  protected void initChannel(NioSocketChannel channel)
+  protected void initChannel(Channel channel)
   {
     if (_ssl)
     {

Diff for: r2-netty/src/main/java/com/linkedin/r2/netty/client/http/HttpChannelPoolFactory.java

@@ -28,12 +28,15 @@
 import io.netty.channel.ChannelInitializer;
 import io.netty.channel.ChannelOption;
 import io.netty.channel.EventLoopGroup;
+import io.netty.channel.epoll.EpollDomainSocketChannel;
 import io.netty.channel.group.ChannelGroup;
 import io.netty.channel.socket.nio.NioSocketChannel;
 import java.net.SocketAddress;
 import java.util.concurrent.ScheduledExecutorService;
 import javax.net.ssl.SSLContext;
 import javax.net.ssl.SSLParameters;
+import org.apache.commons.lang3.StringUtils;
+
 
 /**
  * Factory class to produce {@link AsyncPool}<{@link Channel}> for Http Channels
@@ -53,7 +56,9 @@ public class HttpChannelPoolFactory implements ChannelPoolFactory
   private final ScheduledExecutorService _scheduler;
   private final AsyncPoolImpl.Strategy _strategy;
   private int _channelPoolWaiterTimeout;
+  private final String _udsAddress;
 
+  @Deprecated
   public HttpChannelPoolFactory(
       ScheduledExecutorService scheduler,
       EventLoopGroup eventLoopGroup,
@@ -76,7 +81,36 @@ public HttpChannelPoolFactory(
       int connectTimeout,
       int sslHandShakeTimeout)
   {
-    ChannelInitializer<NioSocketChannel> initializer = new HttpChannelInitializer(sslContext, sslParameters,
+    this( scheduler, eventLoopGroup, channelGroup, strategy, sslContext, sslParameters, maxPoolSize,
+        minPoolSize, maxPoolWaiterSize, maxInitialLineLength, maxHeaderSize, maxChunkSize,
+        maxConcurrentConnectionInitializations, idleTimeout, maxContentLength, tcpNoDelay, enableSSLSessionResumption,
+        channelPoolWaiterTimeout, connectTimeout, sslHandShakeTimeout, null);
+  }
+
+  public HttpChannelPoolFactory(
+      ScheduledExecutorService scheduler,
+      EventLoopGroup eventLoopGroup,
+      ChannelGroup channelGroup,
+      AsyncPoolImpl.Strategy strategy,
+      SSLContext sslContext,
+      SSLParameters sslParameters,
+      int maxPoolSize,
+      int minPoolSize,
+      int maxPoolWaiterSize,
+      int maxInitialLineLength,
+      int maxHeaderSize,
+      int maxChunkSize,
+      int maxConcurrentConnectionInitializations,
+      long idleTimeout,
+      long maxContentLength,
+      boolean tcpNoDelay,
+      boolean enableSSLSessionResumption,
+      int channelPoolWaiterTimeout,
+      int connectTimeout,
+      int sslHandShakeTimeout,
+      String udsAddress)
+  {
+    ChannelInitializer<Channel> initializer = new HttpChannelInitializer(sslContext, sslParameters,
         maxInitialLineLength, maxHeaderSize, maxChunkSize, maxContentLength, enableSSLSessionResumption, sslHandShakeTimeout);
 
     _scheduler = scheduler;
@@ -89,9 +123,22 @@ public HttpChannelPoolFactory(
     _idleTimeout = idleTimeout;
     _tcpNoDelay = tcpNoDelay;
     _channelPoolWaiterTimeout = channelPoolWaiterTimeout;
+    _udsAddress = udsAddress;
 
-    _bootstrap = new Bootstrap().group(eventLoopGroup).channel(NioSocketChannel.class).
-        option(ChannelOption.CONNECT_TIMEOUT_MILLIS, connectTimeout).handler(initializer);
+    if (!StringUtils.isEmpty(_udsAddress)) {
+      _bootstrap = new Bootstrap()
+          .group(eventLoopGroup)
+          .channel(EpollDomainSocketChannel.class)
+          .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, connectTimeout)
+          .handler(initializer);
+    }
+    else{
+      _bootstrap = new Bootstrap()
+          .group(eventLoopGroup)
+          .channel(NioSocketChannel.class)
+          .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, connectTimeout)
+          .handler(initializer);
+    }
   }
 
   @Override

Diff for: r2-netty/src/main/java/com/linkedin/r2/transport/http/client/common/ChannelPoolManagerFactoryImpl.java

@@ -144,7 +144,8 @@ public ChannelPoolManager buildStream(ChannelPoolManagerKey channelPoolManagerKe
           _enableSSLSessionResumption,
           _channelPoolWaiterTimeout,
           _connectTimeout,
-          _sslHandShakeTimeout);
+          _sslHandShakeTimeout,
+          channelPoolManagerKey.getUdsAddress());
     }
     else
     {