Applying #3407 to the 2.1.x branch

spring-cloud-netflix-zuul/src/main/java/org/springframework/cloud/netflix/zuul/filters/route/SimpleHostRoutingFilter.java

@@ -81,6 +81,7 @@ import static org.springframework.cloud.netflix.zuul.filters.support.FilterConst
  * @author Dave Syer
  * @author Bilal Alp
  * @author Gang Li
+ * @author Denys Ivano
  */
 public class SimpleHostRoutingFilter extends ZuulFilter
 		implements ApplicationListener<EnvironmentChangeEvent> {
@@ -132,12 +133,20 @@ public class SimpleHostRoutingFilter extends ZuulFilter
 
 			if (createNewClient) {
 				try {
-					SimpleHostRoutingFilter.this.httpClient.close();
+					this.httpClient.close();
 				}
 				catch (IOException ex) {
 					log.error("error closing client", ex);
 				}
-				SimpleHostRoutingFilter.this.httpClient = newClient();
+				// Re-create connection manager (may be shut down on HTTP client close)
+				try {
+					this.connectionManager.shutdown();
+				}
+				catch (RuntimeException ex) {
+					log.error("error shutting down connection manager", ex);
+				}
+				this.connectionManager = newConnectionManager();
+				this.httpClient = newClient();
 			}
 		}
 	}
@@ -170,12 +179,7 @@ public class SimpleHostRoutingFilter extends ZuulFilter
 	@PostConstruct
 	private void initialize() {
 		if (!customHttpClient) {
-			this.connectionManager = connectionManagerFactory.newConnectionManager(
-					!this.sslHostnameValidationEnabled,
-					this.hostProperties.getMaxTotalConnections(),
-					this.hostProperties.getMaxPerRouteConnections(),
-					this.hostProperties.getTimeToLive(),
-					this.hostProperties.getTimeUnit(), null);
+			this.connectionManager = newConnectionManager();
 			this.httpClient = newClient();
 			this.connectionManagerTimer.schedule(new TimerTask() {
 				@Override
@@ -287,6 +291,15 @@ public class SimpleHostRoutingFilter extends ZuulFilter
 		return connectionManager;
 	}
 
+	protected HttpClientConnectionManager newConnectionManager() {
+		return connectionManagerFactory.newConnectionManager(
+				!this.sslHostnameValidationEnabled,
+				this.hostProperties.getMaxTotalConnections(),
+				this.hostProperties.getMaxPerRouteConnections(),
+				this.hostProperties.getTimeToLive(), this.hostProperties.getTimeUnit(),
+				null);
+	}
+
 	protected CloseableHttpClient newClient() {
 		final RequestConfig requestConfig = RequestConfig.custom()
 				.setConnectionRequestTimeout(

spring-cloud-netflix-zuul/src/test/java/org/springframework/cloud/netflix/zuul/filters/route/SimpleHostRoutingFilterTests.java

@@ -22,7 +22,9 @@ import java.lang.reflect.Field;
 import java.net.URL;
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.HashSet;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicBoolean;
 
 import com.netflix.zuul.context.RequestContext;
 import com.netflix.zuul.monitoring.CounterFactory;
@@ -31,6 +33,7 @@ import org.apache.http.HttpRequest;
 import org.apache.http.client.config.RequestConfig;
 import org.apache.http.client.methods.Configurable;
 import org.apache.http.client.methods.HttpPatch;
+import org.apache.http.conn.HttpClientConnectionManager;
 import org.apache.http.entity.InputStreamEntity;
 import org.apache.http.impl.client.CloseableHttpClient;
 import org.apache.http.impl.client.HttpClientBuilder;
@@ -66,6 +69,7 @@ import static org.springframework.util.StreamUtils.copyToByteArray;
  * @author Andreas Kluth
  * @author Spencer Gibb
  * @author Gang Li
+ * @author Denys Ivano
  */
 public class SimpleHostRoutingFilterTests {
 
@@ -175,16 +179,83 @@ public class SimpleHostRoutingFilterTests {
 	public void zuulHostKeysUpdateHttpClient() {
 		setupContext();
 		SimpleHostRoutingFilter filter = getFilter();
-		CloseableHttpClient httpClient = (CloseableHttpClient) ReflectionTestUtils
-				.getField(filter, "httpClient");
+		CloseableHttpClient httpClient = extractHttpClient(filter);
 		EnvironmentChangeEvent event = new EnvironmentChangeEvent(
 				Collections.singleton("zuul.host.mykey"));
-		filter.onPropertyChange(event);
-		CloseableHttpClient newhttpClient = (CloseableHttpClient) ReflectionTestUtils
-				.getField(filter, "httpClient");
+		filter.onApplicationEvent(event);
+		CloseableHttpClient newhttpClient = extractHttpClient(filter);
 		Assertions.assertThat(httpClient).isNotEqualTo(newhttpClient);
 	}
 
+	private CloseableHttpClient extractHttpClient(SimpleHostRoutingFilter filter) {
+		return (CloseableHttpClient) ReflectionTestUtils.getField(filter, "httpClient");
+	}
+
+	@Test
+	public void zuulHostKeysUpdateHttpClientConnectionManagerIsNotShutDown() {
+		setupContext();
+		SimpleHostRoutingFilter filter = getFilter();
+		EnvironmentChangeEvent event = new EnvironmentChangeEvent(
+				Collections.singleton("zuul.host.mykey"));
+		filter.onApplicationEvent(event);
+
+		CloseableHttpClient httpClient = extractHttpClient(filter);
+		PoolingHttpClientConnectionManager connMgr = (PoolingHttpClientConnectionManager) extractConnectionManager(
+				httpClient);
+		AtomicBoolean isShutDown = getField(connMgr, "isShutDown");
+		assertThat(isShutDown.get()).as("Connection manager shut down").isFalse();
+		Object pool = getField(connMgr, "pool");
+		assertThat(pool).hasFieldOrPropertyWithValue("isShutDown", false);
+	}
+
+	private HttpClientConnectionManager extractConnectionManager(
+			CloseableHttpClient httpClient) {
+		// Default implementation is org.apache.http.impl.client.InternalHttpClient
+		return getField(httpClient, "connManager");
+	}
+
+	@Test
+	public void zuulHostKeysUpdateHttpClientUsesNewConnectionManager() {
+		setupContext();
+		SimpleHostRoutingFilter filter = getFilter();
+		PoolingHttpClientConnectionManager connMgr = (PoolingHttpClientConnectionManager) filter
+				.getConnectionManager();
+		EnvironmentChangeEvent event = new EnvironmentChangeEvent(
+				Collections.singleton("zuul.host.mykey"));
+		filter.onApplicationEvent(event);
+
+		PoolingHttpClientConnectionManager newConnMgr = (PoolingHttpClientConnectionManager) filter
+				.getConnectionManager();
+		CloseableHttpClient httpClient = extractHttpClient(filter);
+		HttpClientConnectionManager usedConnMgr = extractConnectionManager(httpClient);
+		assertThat(usedConnMgr).isNotEqualTo(connMgr);
+		assertThat(usedConnMgr).isEqualTo(newConnMgr);
+	}
+
+	@Test
+	public void zuulHostKeysUpdateConnectionManagerPropertiesAreChanged() {
+		setupContext();
+		SimpleHostRoutingFilter filter = getFilter();
+		ZuulProperties.Host host = context.getBean(ZuulProperties.class).getHost();
+		host.setMaxTotalConnections(50);
+		host.setMaxPerRouteConnections(10);
+		host.setTimeToLive(10);
+		host.setTimeUnit(TimeUnit.SECONDS);
+		EnvironmentChangeEvent event = new EnvironmentChangeEvent(
+				new HashSet<>(Arrays.asList("zuul.host.maxTotalConnections",
+						"zuul.host.maxPerRouteConnections", "zuul.host.timeToLive",
+						"zuul.host.timeUnit")));
+		filter.onApplicationEvent(event);
+
+		PoolingHttpClientConnectionManager connMgr = (PoolingHttpClientConnectionManager) filter
+				.getConnectionManager();
+		assertThat(connMgr.getMaxTotal()).isEqualTo(50);
+		assertThat(connMgr.getDefaultMaxPerRoute()).isEqualTo(10);
+		Object pool = getField(connMgr, "pool");
+		assertThat(pool).hasFieldOrPropertyWithValue("timeToLive", 10L);
+		assertThat(pool).hasFieldOrPropertyWithValue("timeUnit", TimeUnit.SECONDS);
+	}
+
 	@Test
 	public void getRequestBody() throws Exception {
 		setupContext();