Ignore 'Connection: close' header from stream response

This commit resolves an issue where some versions of Cloud Foundry are
setting the 'Connection: close' HTTP header in the Hystrix stream
response, which causes the dashboard to not display the stream data.

See https://github.com/cloudfoundry/gorouter/issues/71

spring-cloud-netflix-hystrix-dashboard/src/main/java/org/springframework/cloud/netflix/hystrix/dashboard/HystrixDashboardConfiguration.java

@@ -37,10 +37,14 @@ import org.apache.http.impl.client.DefaultHttpClient;
 import org.apache.http.impl.conn.PoolingClientConnectionManager;
 import org.apache.http.params.HttpConnectionParams;
 import org.apache.http.params.HttpParams;
+
+import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.autoconfigure.freemarker.FreeMarkerAutoConfiguration;
 import org.springframework.boot.context.embedded.ServletRegistrationBean;
+import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.http.HttpHeaders;
 import org.springframework.ui.freemarker.SpringTemplateLoader;
 import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;
 
@@ -50,12 +54,16 @@ import org.springframework.web.servlet.view.freemarker.FreeMarkerConfigurer;
  */
 @SuppressWarnings("deprecation")
 @Configuration
+@EnableConfigurationProperties(HystrixDashboardProperties.class)
 public class HystrixDashboardConfiguration {
 
 	private static final String DEFAULT_TEMPLATE_LOADER_PATH = "classpath:/templates/";
 
 	private static final String DEFAULT_CHARSET = "UTF-8";
 
+	@Autowired
+	private HystrixDashboardProperties dashboardProperties;
+
 	/**
 	 * Overrides Spring Boot's {@link FreeMarkerAutoConfiguration} to prefer using a
 	 * {@link SpringTemplateLoader} instead of the file system. This corrects an issue
@@ -74,7 +82,10 @@ public class HystrixDashboardConfiguration {
 
 	@Bean
 	public ServletRegistrationBean proxyStreamServlet() {
-		return new ServletRegistrationBean(new ProxyStreamServlet(), "/proxy.stream");
+		ProxyStreamServlet proxyStreamServlet = new ProxyStreamServlet();
+		proxyStreamServlet.setEnableIgnoreConnectionCloseHeader(dashboardProperties
+				.isEnableIgnoreConnectionCloseHeader());
+		return new ServletRegistrationBean(proxyStreamServlet, "/proxy.stream");
 	}
 
 	@Bean
@@ -92,6 +103,15 @@ public class HystrixDashboardConfiguration {
 
 		private static final long serialVersionUID = 1L;
 
+		private static final String CONNECTION_CLOSE_VALUE = "close";
+
+		private boolean enableIgnoreConnectionCloseHeader = false;
+
+		public void setEnableIgnoreConnectionCloseHeader(
+				boolean enableIgnoreConnectionCloseHeader) {
+			this.enableIgnoreConnectionCloseHeader = enableIgnoreConnectionCloseHeader;
+		}
+
 		public ProxyStreamServlet() {
 			super();
 		}
@@ -155,9 +175,7 @@ public class HystrixDashboardConfiguration {
 					is = httpResponse.getEntity().getContent();
 
 					// set headers
-					for (Header header : httpResponse.getAllHeaders()) {
-						response.addHeader(header.getName(), header.getValue());
-					}
+					copyHeadersToServletResponse(httpResponse.getAllHeaders(), response);
 
 					// copy data from source to response
 					OutputStream os = response.getOutputStream();
@@ -217,6 +235,26 @@ public class HystrixDashboardConfiguration {
 					}
 				}
 			}
+
+		}
+
+		private void copyHeadersToServletResponse(Header[] headers,
+				HttpServletResponse response) {
+			for (Header header : headers) {
+				// Some versions of Cloud Foundry (HAProxy) are
+				// incorrectly setting a "Connection: close" header
+				// causing the Hystrix dashboard to close the connection
+				// to the stream
+				// https://github.com/cloudfoundry/gorouter/issues/71
+				if (this.enableIgnoreConnectionCloseHeader
+						&& HttpHeaders.CONNECTION.equalsIgnoreCase(header.getName())
+						&& CONNECTION_CLOSE_VALUE.equalsIgnoreCase(header.getValue())) {
+					log.warn("Ignoring 'Connection: close' header from stream response");
+				}
+				else {
+					response.addHeader(header.getName(), header.getValue());
+				}
+			}
 		}
 
 		private static class ProxyConnectionManager {

spring-cloud-netflix-hystrix-dashboard/src/main/java/org/springframework/cloud/netflix/hystrix/dashboard/HystrixDashboardProperties.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright 2013-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.cloud.netflix.hystrix.dashboard;
+
+import org.springframework.boot.context.properties.ConfigurationProperties;
+
+/**
+ * @author Roy Clarkson
+ */
+@ConfigurationProperties("hystrix.dashboard")
+public class HystrixDashboardProperties {
+
+	/**
+	 * Directs the Hystrix dashboard to ignore 'Connection:close' headers if present in
+	 * the Hystrix response stream
+	 */
+	private boolean enableIgnoreConnectionCloseHeader = false;
+
+	public boolean isEnableIgnoreConnectionCloseHeader() {
+		return enableIgnoreConnectionCloseHeader;
+	}
+
+	public void setEnableIgnoreConnectionCloseHeader(
+			boolean enableIgnoreConnectionCloseHeader) {
+		this.enableIgnoreConnectionCloseHeader = enableIgnoreConnectionCloseHeader;
+	}
+
+}

spring-cloud-netflix-hystrix-dashboard/src/test/java/org/springframework/cloud/netflix/hystrix/dashboard/HystrixDashboardConfigurationTests.java

@@ -0,0 +1,91 @@
+/*
+ * Copyright 2013-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.cloud.netflix.hystrix.dashboard;
+
+import org.apache.http.Header;
+import org.apache.http.message.BasicHeader;
+import org.junit.Test;
+
+import org.springframework.mock.web.MockHttpServletResponse;
+import org.springframework.test.util.ReflectionTestUtils;
+
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertThat;
+
+/**
+ * @author Roy Clarkson
+ */
+public class HystrixDashboardConfigurationTests {
+
+	@Test
+	public void normal() {
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		Header[] headers = new Header[1];
+		headers[0] = new BasicHeader("Content-Type", "text/proxy.stream");
+		HystrixDashboardConfiguration.ProxyStreamServlet proxyStreamServlet = new HystrixDashboardConfiguration.ProxyStreamServlet();
+		ReflectionTestUtils.invokeMethod(proxyStreamServlet,
+				"copyHeadersToServletResponse", headers, response);
+		assertThat(response.getHeaderNames().size(), is(1));
+		assertThat(response.getHeader("Content-Type"), is("text/proxy.stream"));
+	}
+
+	@Test
+	public void connectionClose() {
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		Header[] headers = new Header[2];
+		headers[0] = new BasicHeader("Content-Type", "text/proxy.stream");
+		headers[1] = new BasicHeader("Connection", "close");
+		HystrixDashboardConfiguration.ProxyStreamServlet proxyStreamServlet = new HystrixDashboardConfiguration.ProxyStreamServlet();
+		ReflectionTestUtils.invokeMethod(proxyStreamServlet,
+				"copyHeadersToServletResponse", headers, response);
+		assertThat(response.getHeaderNames().size(), is(2));
+		assertThat(response.getHeader("Content-Type"), is("text/proxy.stream"));
+		assertThat(response.getHeader("Connection"), is("close"));
+	}
+
+	@Test
+	public void ignoreConnectionClose() {
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		Header[] headers = new Header[2];
+		headers[0] = new BasicHeader("Content-Type", "text/proxy.stream");
+		headers[1] = new BasicHeader("Connection", "close");
+		HystrixDashboardConfiguration.ProxyStreamServlet proxyStreamServlet = new HystrixDashboardConfiguration.ProxyStreamServlet();
+		proxyStreamServlet.setEnableIgnoreConnectionCloseHeader(true);
+		ReflectionTestUtils.invokeMethod(proxyStreamServlet,
+				"copyHeadersToServletResponse", headers, response);
+		assertThat(response.getHeaderNames().size(), is(1));
+		assertThat(response.getHeader("Content-Type"), is("text/proxy.stream"));
+		assertNull(response.getHeader("Connection"));
+	}
+
+	@Test
+	public void doNotIgnoreConnectionClose() {
+		MockHttpServletResponse response = new MockHttpServletResponse();
+		Header[] headers = new Header[2];
+		headers[0] = new BasicHeader("Content-Type", "text/proxy.stream");
+		headers[1] = new BasicHeader("Connection", "close");
+		HystrixDashboardConfiguration.ProxyStreamServlet proxyStreamServlet = new HystrixDashboardConfiguration.ProxyStreamServlet();
+		proxyStreamServlet.setEnableIgnoreConnectionCloseHeader(false);
+		ReflectionTestUtils.invokeMethod(proxyStreamServlet,
+				"copyHeadersToServletResponse", headers, response);
+		assertThat(response.getHeaderNames().size(), is(2));
+		assertThat(response.getHeader("Content-Type"), is("text/proxy.stream"));
+		assertThat(response.getHeader("Connection"), is("close"));
+	}
+
+}