cleanup code in router and add forwarding for get requests

server/src/main/java/io/druid/client/RoutingDruidClient.java

@@ -28,7 +28,7 @@ import com.google.common.util.concurrent.ListenableFuture;
 import com.metamx.common.logger.Logger;
 import com.metamx.http.client.HttpClient;
 import com.metamx.http.client.response.HttpResponseHandler;
-import io.druid.guice.annotations.Global;
+import io.druid.guice.annotations.Client;
 import io.druid.query.Query;
 import org.jboss.netty.handler.codec.http.HttpHeaders;
 
@@ -52,7 +52,7 @@ public class RoutingDruidClient<IntermediateType, FinalType>
   @Inject
   public RoutingDruidClient(
       ObjectMapper objectMapper,
-      @Global HttpClient httpClient
+      @Client HttpClient httpClient
   )
   {
     this.objectMapper = objectMapper;
@@ -67,7 +67,7 @@ public class RoutingDruidClient<IntermediateType, FinalType>
     return openConnections.get();
   }
 
-  public ListenableFuture<FinalType> run(
+  public ListenableFuture<FinalType> post(
       String url,
       Query query,
       HttpResponseHandler<IntermediateType, FinalType> responseHandler
@@ -109,4 +109,19 @@ public class RoutingDruidClient<IntermediateType, FinalType>
 
     return future;
   }
+
+  public ListenableFuture<FinalType> get(
+      String url,
+      HttpResponseHandler<IntermediateType, FinalType> responseHandler
+  )
+  {
+    try {
+      return httpClient
+          .get(new URL(url))
+          .go(responseHandler);
+    }
+    catch (IOException e) {
+      throw Throwables.propagate(e);
+    }
+  }
 }

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

@@ -85,6 +85,119 @@ public class AsyncQueryForwardingServlet extends HttpServlet
     this.requestLogger = requestLogger;
   }
 
+  @Override
+  protected void doGet(final HttpServletRequest req, final HttpServletResponse resp)
+      throws ServletException, IOException
+  {
+    OutputStream out = null;
+    AsyncContext ctx = null;
+
+    try {
+      ctx = req.startAsync(req, resp);
+      final AsyncContext asyncContext = ctx;
+
+      if (req.getAttribute(DISPATCHED) != null) {
+        return;
+      }
+
+      out = resp.getOutputStream();
+      final OutputStream outputStream = out;
+
+      final String host = hostFinder.getDefaultHost();
+
+      final HttpResponseHandler<OutputStream, OutputStream> responseHandler = new HttpResponseHandler<OutputStream, OutputStream>()
+      {
+        @Override
+        public ClientResponse<OutputStream> handleResponse(HttpResponse response)
+        {
+          resp.setStatus(response.getStatus().getCode());
+          resp.setContentType("application/json");
+
+          byte[] bytes = getContentBytes(response.getContent());
+          if (bytes.length > 0) {
+            try {
+              outputStream.write(bytes);
+            }
+            catch (Exception e) {
+              asyncContext.complete();
+              throw Throwables.propagate(e);
+            }
+          }
+          return ClientResponse.finished(outputStream);
+        }
+
+        @Override
+        public ClientResponse<OutputStream> handleChunk(
+            ClientResponse<OutputStream> clientResponse, HttpChunk chunk
+        )
+        {
+          byte[] bytes = getContentBytes(chunk.getContent());
+          if (bytes.length > 0) {
+            try {
+              clientResponse.getObj().write(bytes);
+            }
+            catch (Exception e) {
+              asyncContext.complete();
+              throw Throwables.propagate(e);
+            }
+          }
+          return clientResponse;
+        }
+
+        @Override
+        public ClientResponse<OutputStream> done(ClientResponse<OutputStream> clientResponse)
+        {
+          final OutputStream obj = clientResponse.getObj();
+          try {
+            resp.flushBuffer();
+            outputStream.close();
+          }
+          catch (Exception e) {
+            throw Throwables.propagate(e);
+          }
+          finally {
+            asyncContext.complete();
+          }
+
+          return ClientResponse.finished(obj);
+        }
+      };
+
+      asyncContext.start(
+          new Runnable()
+          {
+            @Override
+            public void run()
+            {
+              routingDruidClient.get(makeUrl(host, req), responseHandler);
+            }
+          }
+      );
+
+      asyncContext.dispatch();
+      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();
+    }
+  }
+
   @Override
   protected void doPost(
       final HttpServletRequest req, final HttpServletResponse resp
@@ -99,16 +212,16 @@ public class AsyncQueryForwardingServlet extends HttpServlet
     final ObjectMapper objectMapper = isSmile ? smileMapper : jsonMapper;
 
     OutputStream out = null;
+    AsyncContext ctx = null;
 
     try {
-      final AsyncContext ctx = req.startAsync(req, resp);
+      ctx = req.startAsync(req, resp);
+      final AsyncContext asyncContext = ctx;
 
       if (req.getAttribute(DISPATCHED) != null) {
         return;
       }
 
-      req.setAttribute(DISPATCHED, true);
-
       query = objectMapper.readValue(req.getInputStream(), Query.class);
       queryId = query.getId();
       if (queryId == null) {
@@ -142,6 +255,7 @@ public class AsyncQueryForwardingServlet extends HttpServlet
               outputStream.write(bytes);
             }
             catch (Exception e) {
+              asyncContext.complete();
               throw Throwables.propagate(e);
             }
           }
@@ -159,6 +273,7 @@ public class AsyncQueryForwardingServlet extends HttpServlet
               clientResponse.getObj().write(bytes);
             }
             catch (Exception e) {
+              asyncContext.complete();
               throw Throwables.propagate(e);
             }
           }
@@ -202,30 +317,26 @@ public class AsyncQueryForwardingServlet extends HttpServlet
             throw Throwables.propagate(e);
           }
           finally {
-            ctx.dispatch();
+            asyncContext.complete();
           }
 
           return ClientResponse.finished(obj);
         }
-
-        private byte[] getContentBytes(ChannelBuffer content)
-        {
-          byte[] contentBytes = new byte[content.readableBytes()];
-          content.readBytes(contentBytes);
-          return contentBytes;
-        }
       };
 
-      ctx.start(
+      asyncContext.start(
           new Runnable()
           {
             @Override
             public void run()
             {
-              routingDruidClient.run(makeUrl(host, req), theQuery, responseHandler);
+              routingDruidClient.post(makeUrl(host, req), theQuery, responseHandler);
             }
           }
       );
+
+      asyncContext.dispatch();
+      req.setAttribute(DISPATCHED, true);
     }
     catch (Exception e) {
       if (!resp.isCommitted()) {
@@ -242,6 +353,10 @@ public class AsyncQueryForwardingServlet extends HttpServlet
 
       resp.flushBuffer();
 
+      if (ctx != null) {
+        ctx.complete();
+      }
+
       try {
         requestLogger.log(
             new RequestLogLine(
@@ -272,4 +387,11 @@ public class AsyncQueryForwardingServlet extends HttpServlet
     }
     return String.format("http://%s%s?%s", host, req.getRequestURI(), req.getQueryString());
   }
+
+  private byte[] getContentBytes(ChannelBuffer content)
+  {
+    byte[] contentBytes = new byte[content.readableBytes()];
+    content.readBytes(contentBytes);
+    return contentBytes;
+  }
 }

server/src/main/java/io/druid/server/router/QueryHostFinder.java

@@ -49,7 +49,49 @@ public class QueryHostFinder<T>
   public Server findServer(Query<T> query)
   {
     final Pair<String, ServerDiscoverySelector> selected = hostSelector.select(query);
+    return findServerInner(selected);
+  }
+
+  public Server findDefaultServer()
+  {
+    final Pair<String, ServerDiscoverySelector> selected = hostSelector.getDefaultLookup();
+    return findServerInner(selected);
+  }
+
+  public String getHost(Query<T> query)
+  {
+    Server server = findServer(query);
+
+    if (server == null) {
+      log.makeAlert(
+          "Catastrophic failure! No servers found at all! Failing request!"
+      ).emit();
+
+      return null;
+    }
+
+    log.debug("Selected [%s]", server.getHost());
+
+    return server.getHost();
+  }
+
+  public String getDefaultHost()
+  {
+    Server server = findDefaultServer();
+
+    if (server == null) {
+      log.makeAlert(
+          "Catastrophic failure! No servers found at all! Failing request!"
+      ).emit();
 
+      return null;
+    }
+
+    return server.getHost();
+  }
+
+  private Server findServerInner(final Pair<String, ServerDiscoverySelector> selected)
+  {
     if (selected == null) {
       log.error("Danger, Will Robinson! Unable to find any brokers!");
     }
@@ -82,21 +124,4 @@ public class QueryHostFinder<T>
 
     return server;
   }
-
-  public String getHost(Query<T> query)
-  {
-    Server server = findServer(query);
-
-    if (server == null) {
-      log.makeAlert(
-          "Catastrophic failure! No servers found at all! Failing request!"
-      ).emit();
-
-      return null;
-    }
-
-    log.debug("Selected [%s]", server.getHost());
-
-    return server.getHost();
-  }
 }

server/src/main/java/io/druid/server/router/TieredBrokerHostSelector.java

@@ -193,7 +193,7 @@ public class TieredBrokerHostSelector<T> implements HostSelector<T>
     return new Pair<>(brokerServiceName, retVal);
   }
 
-  private Pair<String, ServerDiscoverySelector> getDefaultLookup()
+  public Pair<String, ServerDiscoverySelector> getDefaultLookup()
   {
     final String brokerServiceName = tierConfig.getDefaultBrokerServiceName();
     final ServerDiscoverySelector retVal = selectorMap.get(brokerServiceName);

services/src/main/java/io/druid/cli/CliRouter.java

@@ -29,10 +29,12 @@ import io.druid.client.RoutingDruidClient;
 import io.druid.curator.discovery.DiscoveryModule;
 import io.druid.curator.discovery.ServerDiscoveryFactory;
 import io.druid.curator.discovery.ServerDiscoverySelector;
+import io.druid.guice.HttpClientModule;
 import io.druid.guice.JsonConfigProvider;
 import io.druid.guice.LazySingleton;
 import io.druid.guice.LifecycleModule;
 import io.druid.guice.ManageLifecycle;
+import io.druid.guice.annotations.Client;
 import io.druid.guice.annotations.Self;
 import io.druid.server.initialization.JettyServerInitializer;
 import io.druid.server.router.CoordinatorRuleManager;
@@ -62,6 +64,7 @@ public class CliRouter extends ServerRunnable
   protected List<Object> getModules()
   {
     return ImmutableList.<Object>of(
+        new HttpClientModule("druid.router.http", Client.class),
         new Module()
         {
           @Override