Introduce an option for tuning SO_KEEPALIVE, close AsyncHttpClient#1702

Motivation:

We don't set SO_KEEPALIVE on the socket.

Modification:

Enable SO_KEEPALIVE by default and introduce org.asynchttpclient.soKeepAlive config option to disable it.

Result:

SO_KEEPALIVE supported

Author: slandelle

client/src/main/java/org/asynchttpclient/AsyncHttpClientConfig.java

@@ -318,6 +318,8 @@ public interface AsyncHttpClientConfig {
 
   boolean isSoReuseAddress();
 
+  boolean isSoKeepAlive();
+
   int getSoLinger();
 
   int getSoSndBuf();

client/src/main/java/org/asynchttpclient/DefaultAsyncHttpClientConfig.java

@@ -123,6 +123,7 @@ public class DefaultAsyncHttpClientConfig implements AsyncHttpClientConfig {
   private final ByteBufAllocator allocator;
   private final boolean tcpNoDelay;
   private final boolean soReuseAddress;
+  private final boolean soKeepAlive;
   private final int soLinger;
   private final int soSndBuf;
   private final int soRcvBuf;
@@ -193,6 +194,7 @@ private DefaultAsyncHttpClientConfig(// http
                                        // tuning
                                        boolean tcpNoDelay,
                                        boolean soReuseAddress,
+                                       boolean soKeepAlive,
                                        int soLinger,
                                        int soSndBuf,
                                        int soRcvBuf,
@@ -281,6 +283,7 @@ private DefaultAsyncHttpClientConfig(// http
     // tuning
     this.tcpNoDelay = tcpNoDelay;
     this.soReuseAddress = soReuseAddress;
+    this.soKeepAlive = soKeepAlive;
     this.soLinger = soLinger;
     this.soSndBuf = soSndBuf;
     this.soRcvBuf = soRcvBuf;
@@ -560,6 +563,11 @@ public boolean isSoReuseAddress() {
     return soReuseAddress;
   }
 
+  @Override
+  public boolean isSoKeepAlive() {
+    return soKeepAlive;
+  }
+
   @Override
   public int getSoLinger() {
     return soLinger;
@@ -726,6 +734,7 @@ public static class Builder {
     // tuning
     private boolean tcpNoDelay = defaultTcpNoDelay();
     private boolean soReuseAddress = defaultSoReuseAddress();
+    private boolean soKeepAlive = defaultSoKeepAlive();
     private int soLinger = defaultSoLinger();
     private int soSndBuf = defaultSoSndBuf();
     private int soRcvBuf = defaultSoRcvBuf();
@@ -808,6 +817,7 @@ public Builder(AsyncHttpClientConfig config) {
       // tuning
       tcpNoDelay = config.isTcpNoDelay();
       soReuseAddress = config.isSoReuseAddress();
+      soKeepAlive = config.isSoKeepAlive();
       soLinger = config.getSoLinger();
       soSndBuf = config.getSoSndBuf();
       soRcvBuf = config.getSoRcvBuf();
@@ -1127,6 +1137,11 @@ public Builder setSoReuseAddress(boolean soReuseAddress) {
       return this;
     }
 
+    public Builder setSoKeepAlive(boolean soKeepAlive) {
+      this.soKeepAlive = soKeepAlive;
+      return this;
+    }
+
     public Builder setSoLinger(int soLinger) {
       this.soLinger = soLinger;
       return this;
@@ -1287,6 +1302,7 @@ public DefaultAsyncHttpClientConfig build() {
               cookieStore,
               tcpNoDelay,
               soReuseAddress,
+              soKeepAlive,
               soLinger,
               soSndBuf,
               soRcvBuf,

client/src/main/java/org/asynchttpclient/config/AsyncHttpClientConfigDefaults.java

@@ -53,6 +53,7 @@ public final class AsyncHttpClientConfigDefaults {
   public static final String SSL_SESSION_TIMEOUT_CONFIG = "sslSessionTimeout";
   public static final String TCP_NO_DELAY_CONFIG = "tcpNoDelay";
   public static final String SO_REUSE_ADDRESS_CONFIG = "soReuseAddress";
+  public static final String SO_KEEP_ALIVE_CONFIG = "soKeepAlive";
   public static final String SO_LINGER_CONFIG = "soLinger";
   public static final String SO_SND_BUF_CONFIG = "soSndBuf";
   public static final String SO_RCV_BUF_CONFIG = "soRcvBuf";
@@ -222,6 +223,10 @@ public static boolean defaultSoReuseAddress() {
     return AsyncHttpClientConfigHelper.getAsyncHttpClientConfig().getBoolean(ASYNC_CLIENT_CONFIG_ROOT + SO_REUSE_ADDRESS_CONFIG);
   }
 
+  public static boolean defaultSoKeepAlive() {
+    return AsyncHttpClientConfigHelper.getAsyncHttpClientConfig().getBoolean(ASYNC_CLIENT_CONFIG_ROOT + SO_KEEP_ALIVE_CONFIG);
+  }
+
   public static int defaultSoLinger() {
     return AsyncHttpClientConfigHelper.getAsyncHttpClientConfig().getInt(ASYNC_CLIENT_CONFIG_ROOT + SO_LINGER_CONFIG);
   }

client/src/main/java/org/asynchttpclient/netty/channel/ChannelManager.java

@@ -162,6 +162,7 @@ private Bootstrap newBootstrap(ChannelFactory<? extends Channel> channelFactory,
             .option(ChannelOption.ALLOCATOR, config.getAllocator() != null ? config.getAllocator() : ByteBufAllocator.DEFAULT)
             .option(ChannelOption.TCP_NODELAY, config.isTcpNoDelay())
             .option(ChannelOption.SO_REUSEADDR, config.isSoReuseAddress())
+            .option(ChannelOption.SO_KEEPALIVE, config.isSoKeepAlive())
             .option(ChannelOption.AUTO_CLOSE, false);
 
     if (config.getConnectTimeout() > 0) {

client/src/main/resources/org/asynchttpclient/config/ahc-default.properties

@@ -32,6 +32,7 @@ org.asynchttpclient.sslSessionCacheSize=0
 org.asynchttpclient.sslSessionTimeout=0
 org.asynchttpclient.tcpNoDelay=true
 org.asynchttpclient.soReuseAddress=false
+org.asynchttpclient.soKeepAlive=true
 org.asynchttpclient.soLinger=-1
 org.asynchttpclient.soSndBuf=-1
 org.asynchttpclient.soRcvBuf=-1

extras/typesafeconfig/src/main/java/org/asynchttpclient/extras/typesafeconfig/AsyncHttpClientTypesafeConfig.java

@@ -369,6 +369,11 @@ public boolean isSoReuseAddress() {
     return getBooleanOpt(SO_REUSE_ADDRESS_CONFIG).orElse(defaultSoReuseAddress());
   }
 
+  @Override
+  public boolean isSoKeepAlive() {
+    return getBooleanOpt(SO_KEEP_ALIVE_CONFIG).orElse(defaultSoKeepAlive());
+  }
+
   @Override
   public int getSoLinger() {
     return getIntegerOpt(SO_LINGER_CONFIG).orElse(defaultSoLinger());