Fix to ApacheHttpClient to allow socket keepalive

Author: ajs139

.changes/next-release/feature-AWSSDKforJavav2-31396bc.json

@@ -0,0 +1,6 @@
+{
+    "category": "AWS SDK for Java v2", 
+    "contributor": "ajs139", 
+    "type": "feature", 
+    "description": "Add a configuration option to enable `TCP_KEEPALIVE` on the ApacheHttpClient."
+}

http-client-spi/src/main/java/software/amazon/awssdk/http/SdkHttpConfigurationOption.java

@@ -90,6 +90,12 @@ public final class SdkHttpConfigurationOption<T> extends AttributeMap.Key<T> {
     public static final SdkHttpConfigurationOption<Boolean> REAP_IDLE_CONNECTIONS =
             new SdkHttpConfigurationOption<>("ReapIdleConnections", Boolean.class);
 
+    /**
+     * Whether or not to use keepalive on the connection.
+     */
+    public static final SdkHttpConfigurationOption<Boolean> TCP_KEEPALIVE =
+        new SdkHttpConfigurationOption<>("TcpKeepalive", Boolean.class);
+
     /**
      * The {@link TlsKeyManagersProvider} that will be used by the HTTP client when authenticating with a
      * TLS host.
@@ -120,6 +126,7 @@ public final class SdkHttpConfigurationOption<T> extends AttributeMap.Key<T> {
     private static final Boolean DEFAULT_REAP_IDLE_CONNECTIONS = Boolean.TRUE;
     private static final int DEFAULT_MAX_CONNECTIONS = 50;
     private static final int DEFAULT_MAX_CONNECTION_ACQUIRES = 10_000;
+    private static final Boolean DEFAULT_TCP_KEEPALIVE = Boolean.FALSE;
     private static final Boolean DEFAULT_TRUST_ALL_CERTIFICATES = Boolean.FALSE;
 
     private static final Protocol DEFAULT_PROTOCOL = Protocol.HTTP1_1;
@@ -140,6 +147,7 @@ public final class SdkHttpConfigurationOption<T> extends AttributeMap.Key<T> {
             .put(PROTOCOL, DEFAULT_PROTOCOL)
             .put(TRUST_ALL_CERTIFICATES, DEFAULT_TRUST_ALL_CERTIFICATES)
             .put(REAP_IDLE_CONNECTIONS, DEFAULT_REAP_IDLE_CONNECTIONS)
+            .put(TCP_KEEPALIVE, DEFAULT_TCP_KEEPALIVE)
             .put(TLS_KEY_MANAGERS_PROVIDER, DEFAULT_TLS_KEY_MANAGERS_PROVIDER)
             .put(TLS_TRUST_MANAGERS_PROVIDER, DEFAULT_TLS_TRUST_MANAGERS_PROVIDER)
             .build();

http-clients/apache-client/src/main/java/software/amazon/awssdk/http/apache/ApacheHttpClient.java

@@ -405,6 +405,11 @@ public interface Builder extends SdkHttpClient.Builder<ApacheHttpClient.Builder>
          */
         Builder credentialsProvider(CredentialsProvider credentialsProvider);
 
+        /**
+         * Configure the socket to use java.net.SocketOptions.SO_KEEPALIVE.
+         */
+        Builder tcpKeepAlive(Boolean keepConnectionAlive);
+
         /**
          * Configure the {@link TlsKeyManagersProvider} that will provide the {@link javax.net.ssl.KeyManager}s to use
          * when constructing the SSL context.
@@ -559,6 +564,16 @@ public void setCredentialsProvider(CredentialsProvider credentialsProvider) {
             credentialsProvider(credentialsProvider);
         }
 
+        @Override
+        public Builder tcpKeepAlive(Boolean keepConnectionAlive) {
+            standardOptions.put(SdkHttpConfigurationOption.TCP_KEEPALIVE, keepConnectionAlive);
+            return this;
+        }
+
+        public void setTcpKeepAlive(Boolean keepConnectionAlive) {
+            tcpKeepAlive(keepConnectionAlive);
+        }
+
         @Override
         public Builder tlsKeyManagersProvider(TlsKeyManagersProvider tlsKeyManagersProvider) {
             standardOptions.put(SdkHttpConfigurationOption.TLS_KEY_MANAGERS_PROVIDER, tlsKeyManagersProvider);
@@ -677,8 +692,7 @@ public X509Certificate[] getAcceptedIssuers() {
 
         private SocketConfig buildSocketConfig(AttributeMap standardOptions) {
             return SocketConfig.custom()
-                               // TODO do we want to keep SO keep alive
-                               .setSoKeepAlive(false)
+                               .setSoKeepAlive(standardOptions.get(SdkHttpConfigurationOption.TCP_KEEPALIVE))
                                .setSoTimeout(
                                        saturatedCast(standardOptions.get(SdkHttpConfigurationOption.READ_TIMEOUT)
                                                                     .toMillis()))