Allow customization of HttpClient.

Uses ribbon settings to set MaxConnTotal and MaxConnPerRoute. Also allows user to create a custom HttpClient as a constructor argument.

fixes gh-1149

spring-cloud-netflix-core/src/main/java/org/springframework/cloud/netflix/ribbon/apache/RibbonLoadBalancingHttpClient.java

@@ -43,30 +43,53 @@ import static org.springframework.cloud.netflix.ribbon.RibbonUtils.updateToHttps
 public class RibbonLoadBalancingHttpClient
 		extends
 		AbstractLoadBalancingClient<RibbonApacheHttpRequest, RibbonApacheHttpResponse> {
-	private final HttpClient delegate = HttpClientBuilder.create().disableCookieManagement().build();
+	private final HttpClient delegate;
 	private final IClientConfig config;
 	private final ServerIntrospector serverIntrospector;
 
 	@Deprecated
 	public RibbonLoadBalancingHttpClient() {
-		super();
-		this.config = new DefaultClientConfigImpl();
-		this.serverIntrospector = new DefaultServerIntrospector();
+		this(new DefaultClientConfigImpl(), new DefaultServerIntrospector());
 	}
 
 	@Deprecated
 	public RibbonLoadBalancingHttpClient(final ILoadBalancer lb) {
 		super(lb);
 		this.config = new DefaultClientConfigImpl();
+		this.delegate = createHttpClient(this.config);
 		this.serverIntrospector = new DefaultServerIntrospector();
+		initWithNiwsConfig(config);
 	}
 
 	public RibbonLoadBalancingHttpClient(IClientConfig config, ServerIntrospector serverIntrospector) {
+		this.delegate = createHttpClient(config);
 		this.config = config;
 		this.serverIntrospector = serverIntrospector;
 		initWithNiwsConfig(config);
 	}
 
+	public RibbonLoadBalancingHttpClient(HttpClient delegate, IClientConfig config, ServerIntrospector serverIntrospector) {
+		this.delegate = delegate;
+		this.config = config;
+		this.serverIntrospector = serverIntrospector;
+		initWithNiwsConfig(config);
+	}
+
+	protected HttpClient createHttpClient(IClientConfig config) {
+		return HttpClientBuilder.create()
+				// already defaults to 0 in builder, so resetting to 0 won't hurt
+				.setMaxConnTotal(config.getPropertyAsInteger(CommonClientConfigKey.MaxTotalConnections, 0))
+				// already defaults to 0 in builder, so resetting to 0 won't hurt
+				.setMaxConnPerRoute(config.getPropertyAsInteger(CommonClientConfigKey.MaxConnectionsPerHost, 0))
+				.disableCookieManagement()
+				.useSystemProperties() // for proxy
+				.build();
+	}
+
+	protected HttpClient getDelegate() {
+		return this.delegate;
+	}
+
 	@Override
 	public RibbonApacheHttpResponse execute(RibbonApacheHttpRequest request,
 			final IClientConfig configOverride) throws Exception {

spring-cloud-netflix-core/src/test/java/org/springframework/cloud/netflix/ribbon/apache/RibbonLoadBalancingHttpClientTests.java

@@ -20,6 +20,7 @@ import org.apache.http.HttpResponse;
 import org.apache.http.client.HttpClient;
 import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.HttpUriRequest;
+import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
 import org.junit.Test;
 import org.mockito.ArgumentCaptor;
 import org.springframework.cloud.netflix.ribbon.RibbonAutoConfiguration;
@@ -73,6 +74,20 @@ public class RibbonLoadBalancingHttpClientTests {
 		assertThat(result.getSocketTimeout(), is (50000));
 	}
 
+	@Test
+	public void testConnections() throws Exception {
+		SpringClientFactory factory = new SpringClientFactory();
+		factory.setApplicationContext(new AnnotationConfigApplicationContext(
+				RibbonAutoConfiguration.class, Connections.class));
+		RibbonLoadBalancingHttpClient client = factory.getClient("service",
+				RibbonLoadBalancingHttpClient.class);
+
+		HttpClient delegate = client.getDelegate();
+		PoolingHttpClientConnectionManager connManager = (PoolingHttpClientConnectionManager) ReflectionTestUtils.getField(delegate, "connManager");
+		assertThat(connManager.getMaxTotal(), is(101));
+		assertThat(connManager.getDefaultMaxPerRoute(), is(201));
+	}
+
 	@Test
 	public void testRequestConfigDoNotFollowRedirectsOverrideWithFollowRedirects()
 			throws Exception {
@@ -135,6 +150,18 @@ public class RibbonLoadBalancingHttpClientTests {
 		}
 	}
 
+
+	@Configuration
+	protected static class Connections {
+		@Bean
+		public IClientConfig clientConfig() {
+			DefaultClientConfigImpl config = new DefaultClientConfigImpl();
+			config.set(CommonClientConfigKey.MaxTotalConnections, 101);
+			config.set(CommonClientConfigKey.MaxConnectionsPerHost, 201);
+			return config;
+		}
+	}
+
 	private RequestConfig getBuiltRequestConfig(Class<?> defaultConfigurationClass,
 			IClientConfig configOverride) throws Exception {