fix jetty threads getting stuck

Fix Jetty threads getting stuck on exceptions

pom.xml

@@ -79,7 +79,7 @@
             <dependency>
                 <groupId>com.metamx</groupId>
                 <artifactId>http-client</artifactId>
-                <version>0.9.4</version>
+                <version>0.9.5</version>
             </dependency>
             <dependency>
                 <groupId>com.metamx</groupId>

server/src/main/java/io/druid/server/AsyncQueryForwardingServlet.java

@@ -42,6 +42,7 @@ import org.joda.time.DateTime;
 
 import javax.servlet.AsyncContext;
 import javax.servlet.ServletException;
+import javax.servlet.ServletOutputStream;
 import javax.servlet.annotation.WebServlet;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
@@ -159,6 +160,15 @@ public class AsyncQueryForwardingServlet extends HttpServlet
 
           return ClientResponse.finished(obj);
         }
+
+        @Override
+        public void exceptionCaught(
+            ClientResponse<OutputStream> clientResponse,
+            Throwable e
+        )
+        {
+          handleException(resp, asyncContext, e);
+        }
       };
 
       asyncContext.start(
@@ -176,23 +186,7 @@ public class AsyncQueryForwardingServlet extends HttpServlet
       req.setAttribute(DISPATCHED, true);
     }
     catch (Exception e) {
-      if (!resp.isCommitted()) {
-        resp.setStatus(500);
-        resp.resetBuffer();
-
-        if (out == null) {
-          out = resp.getOutputStream();
-        }
-
-        if (ctx != null) {
-          ctx.complete();
-        }
-
-        out.write((e.getMessage() == null) ? "Exception null".getBytes(UTF8) : e.getMessage().getBytes(UTF8));
-        out.write("\n".getBytes(UTF8));
-      }
-
-      resp.flushBuffer();
+      handleException(resp, ctx,  e);
     }
   }
 
@@ -316,6 +310,15 @@ public class AsyncQueryForwardingServlet extends HttpServlet
 
           return ClientResponse.finished(obj);
         }
+
+        @Override
+        public void exceptionCaught(
+            ClientResponse<OutputStream> clientResponse,
+            Throwable e
+        )
+        {
+          handleException(resp, asyncContext, e);
+        }
       };
 
       asyncContext.start(
@@ -333,23 +336,7 @@ public class AsyncQueryForwardingServlet extends HttpServlet
       req.setAttribute(DISPATCHED, true);
     }
     catch (Exception e) {
-      if (!resp.isCommitted()) {
-        resp.setStatus(500);
-        resp.resetBuffer();
-
-        if (out == null) {
-          out = resp.getOutputStream();
-        }
-
-        out.write((e.getMessage() == null) ? "Exception null".getBytes(UTF8) : e.getMessage().getBytes(UTF8));
-        out.write("\n".getBytes(UTF8));
-      }
-
-      resp.flushBuffer();
-
-      if (ctx != null) {
-        ctx.complete();
-      }
+      handleException(resp, ctx, e);
 
       try {
         requestLogger.log(
@@ -382,4 +369,25 @@ public class AsyncQueryForwardingServlet extends HttpServlet
     }
     return String.format("http://%s%s?%s", host, requestURI, queryString);
   }
+
+  private static void handleException(HttpServletResponse resp, AsyncContext ctx, Throwable e)
+  {
+    try {
+      final ServletOutputStream out = resp.getOutputStream();
+      if (!resp.isCommitted()) {
+        resp.setStatus(500);
+        resp.resetBuffer();
+        out.write((e.getMessage() == null) ? "Exception null".getBytes(UTF8) : e.getMessage().getBytes(UTF8));
+        out.write("\n".getBytes(UTF8));
+      }
+
+      if (ctx != null) {
+        ctx.complete();
+      }
+      resp.flushBuffer();
+    }
+    catch (IOException e1) {
+      Throwables.propagate(e1);
+    }
+  }
 }

server/src/test/java/io/druid/server/initialization/JettyTest.java

@@ -17,7 +17,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  */
 
-package io.druid;
+package io.druid.server.initialization;
 
 import com.google.common.collect.Lists;
 import com.google.common.util.concurrent.ListenableFuture;
@@ -28,13 +28,14 @@ import com.google.inject.Module;
 import com.google.inject.servlet.GuiceFilter;
 import com.metamx.common.lifecycle.Lifecycle;
 import com.metamx.http.client.HttpClient;
+import com.metamx.http.client.response.InputStreamResponseHandler;
 import com.metamx.http.client.response.StatusResponseHandler;
 import com.metamx.http.client.response.StatusResponseHolder;
 import io.druid.guice.Jerseys;
 import io.druid.guice.LazySingleton;
 import io.druid.guice.annotations.Global;
 import io.druid.initialization.Initialization;
-import io.druid.server.initialization.JettyServerInitializer;
+import org.apache.commons.io.IOUtils;
 import org.eclipse.jetty.server.Handler;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.handler.DefaultHandler;
@@ -43,13 +44,22 @@ import org.eclipse.jetty.servlet.DefaultServlet;
 import org.eclipse.jetty.servlet.ServletContextHandler;
 import org.eclipse.jetty.servlet.ServletHolder;
 import org.eclipse.jetty.servlets.GzipFilter;
+import org.junit.After;
+import org.junit.Assert;
+import org.junit.Before;
 import org.junit.Ignore;
 import org.junit.Test;
 
+import javax.servlet.ServletOutputStream;
+import javax.servlet.http.HttpServletResponse;
 import javax.ws.rs.GET;
 import javax.ws.rs.Path;
 import javax.ws.rs.Produces;
+import javax.ws.rs.core.Context;
 import javax.ws.rs.core.Response;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.StringWriter;
 import java.net.URL;
 import java.nio.charset.Charset;
 import java.util.Random;
@@ -61,6 +71,9 @@ import java.util.concurrent.atomic.AtomicLong;
 
 public class JettyTest
 {
+  private Lifecycle lifecycle;
+  private HttpClient client;
+
   public static void setProperties()
   {
     System.setProperty("druid.host", "localhost:9999");
@@ -71,11 +84,9 @@ public class JettyTest
     System.setProperty("druid.global.http.readTimeout", "PT1S");
   }
 
-  @Test @Ignore // this test will deadlock if it hits an issue, so ignored by default
-  public void testTimeouts() throws Exception
+  @Before
+  public void setup() throws Exception
   {
-    // test for request timeouts properly not locking up all threads
-
     setProperties();
     Injector injector = Initialization.makeInjectorWithModules(
         Initialization.makeStartupInjector(), Lists.<Object>newArrayList(
@@ -86,17 +97,24 @@ public class JettyTest
           {
             binder.bind(JettyServerInitializer.class).to(JettyServerInit.class).in(LazySingleton.class);
             Jerseys.addResource(binder, SlowResource.class);
-
+            Jerseys.addResource(binder, ExceptionResource.class);
           }
         }
     )
     );
-    Lifecycle lifecycle = injector.getInstance(Lifecycle.class);
+    lifecycle = injector.getInstance(Lifecycle.class);
     // Jetty is Lazy Initialized do a getInstance
     injector.getInstance(Server.class);
     lifecycle.start();
     ClientHolder holder = injector.getInstance(ClientHolder.class);
-    final HttpClient client = holder.getClient();
+    client = holder.getClient();
+  }
+
+  @Test
+  @Ignore // this test will deadlock if it hits an issue, so ignored by default
+  public void testTimeouts() throws Exception
+  {
+    // test for request timeouts properly not locking up all threads
     final Executor executor = Executors.newFixedThreadPool(100);
     final AtomicLong count = new AtomicLong(0);
     final CountDownLatch latch = new CountDownLatch(1000);
@@ -149,8 +167,35 @@ public class JettyTest
     }
 
     latch.await();
-    lifecycle.stop();
+  }
+
+  // Tests that threads are not stuck when partial chunk is not finalized
+  // https://bugs.eclipse.org/bugs/show_bug.cgi?id=424107
+  @Test
+  public void testChunkNotFinalized() throws Exception
+  {
+    ListenableFuture<InputStream> go = client.get(
+        new URL(
+            "http://localhost:9999/exception/exception"
+        )
+
+    )
+                                             .go(new InputStreamResponseHandler());
+    try {
+      StringWriter writer = new StringWriter();
+      IOUtils.copy(go.get(), writer, "utf-8");
+      Assert.fail("Should have thrown Exception");
+    }
+    catch (IOException e) {
+      // Expected.
+    }
+
+  }
 
+  @After
+  public void teardown()
+  {
+    lifecycle.stop();
   }
 
   public static class ClientHolder
@@ -206,4 +251,27 @@ public class JettyTest
       return Response.ok("hello").build();
     }
   }
+
+  @Path("/exception")
+  public static class ExceptionResource
+  {
+    @GET
+    @Path("/exception")
+    @Produces("application/json")
+    public Response exception(
+        @Context HttpServletResponse resp
+    ) throws IOException
+    {
+      final ServletOutputStream outputStream = resp.getOutputStream();
+      outputStream.println("hello");
+      outputStream.flush();
+      try {
+        TimeUnit.MILLISECONDS.sleep(200);
+      }
+      catch (InterruptedException e) {
+        //
+      }
+      throw new IOException();
+    }
+  }
 }