Add thread pool option to NonblockingServer

Summary: If you want requests processed outside of the I/O thread

Reviewed By: jake luciani, aditya

Test Plan: nb-main.cpp, in the test folder


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665132 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/cpp/src/server/TNonblockingServer.cpp b/lib/cpp/src/server/TNonblockingServer.cpp
index 6337806..5c4dc8c 100644
--- a/lib/cpp/src/server/TNonblockingServer.cpp
+++ b/lib/cpp/src/server/TNonblockingServer.cpp
@@ -6,6 +6,7 @@
 
 #include "TNonblockingServer.h"
 
+#include <iostream>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
@@ -17,6 +18,50 @@
 
 using namespace facebook::thrift::protocol;
 using namespace facebook::thrift::transport;
+using namespace std;
+
+class TConnection::Task: public Runnable {
+ public:
+  Task(boost::shared_ptr<TProcessor> processor,
+       boost::shared_ptr<TProtocol> input,
+       boost::shared_ptr<TProtocol> output,
+       int taskHandle) :
+    processor_(processor),
+    input_(input),
+    output_(output),
+    taskHandle_(taskHandle) {}
+
+  void run() {
+    try {
+      while (processor_->process(input_, output_)) {
+        if (!input_->getTransport()->peek()) {
+          break;
+        }
+      }
+    } catch (TTransportException& ttx) {
+      cerr << "TThreadedServer client died: " << ttx.what() << endl;
+    } catch (TException& x) {
+      cerr << "TThreadedServer exception: " << x.what() << endl;
+    } catch (...) {
+      cerr << "TThreadedServer uncaught exception." << endl;
+    }
+    
+    // Signal completion back to the libevent thread via a socketpair
+    int8_t b = 0;
+    if (-1 == send(taskHandle_, &b, sizeof(int8_t), 0)) {
+      GlobalOutput("TNonblockingServer::Task: send");
+    }
+    if (-1 == ::close(taskHandle_)) {
+      GlobalOutput("TNonblockingServer::Task: close, possible resource leak");
+    }
+  }
+
+ private:
+  boost::shared_ptr<TProcessor> processor_;
+  boost::shared_ptr<TProtocol> input_;
+  boost::shared_ptr<TProtocol> output_;
+  int taskHandle_;
+};
 
 void TConnection::init(int socket, short eventFlags, TNonblockingServer* s) {
   socket_ = socket;
@@ -34,6 +79,8 @@
   socketState_ = SOCKET_RECV;
   appState_ = APP_INIT;
   
+  taskHandle_ = -1;
+
   // Set flags, which also registers the event
   setFlags(eventFlags);
 
@@ -168,24 +215,59 @@
     // and get back some data from the dispatch function
     inputTransport_->resetBuffer(readBuffer_, readBufferPos_);
     outputTransport_->resetBuffer();
+  
+    if (server_->isThreadPoolProcessing()) {
+      // We are setting up a Task to do this work and we will wait on it
+      int sv[2];
+      if (-1 == socketpair(AF_LOCAL, SOCK_STREAM, 0, sv)) {
+        GlobalOutput("TConnection::socketpair() failed");
+        // Now we will fall through to the APP_WAIT_TASK block with no response
+      } else {
+        // Create task and dispatch to the thread manager
+        boost::shared_ptr<Runnable> task =
+          boost::shared_ptr<Runnable>(new Task(server_->getProcessor(),
+                                               inputProtocol_,
+                                               outputProtocol_,
+                                               sv[1]));
+        appState_ = APP_WAIT_TASK;
+        event_set(&taskEvent_,
+                  taskHandle_ = sv[0],
+                  EV_READ,
+                  TConnection::taskHandler,
+                  this);
 
-    try {
-      // Invoke the processor
-      server_->getProcessor()->process(inputProtocol_, outputProtocol_);
-    } catch (TTransportException &ttx) {
-      fprintf(stderr, "TTransportException: Server::process() %s\n", ttx.what());
-      close();
-      return;
-    } catch (TException &x) {
-      fprintf(stderr, "TException: Server::process() %s\n", x.what());
-      close();     
-      return;
-    } catch (...) {
-      fprintf(stderr, "Server::process() unknown exception\n");
-      close();
-      return;
+        // Add the event and start up the server
+        if (-1 == event_add(&taskEvent_, 0)) {
+          GlobalOutput("TNonblockingServer::serve(): coult not event_add");
+          return;
+        }
+        server_->addTask(task);
+        return;
+      }
+    } else {
+      try {
+        // Invoke the processor
+        server_->getProcessor()->process(inputProtocol_, outputProtocol_);
+      } catch (TTransportException &ttx) {
+        fprintf(stderr, "TTransportException: Server::process() %s\n", ttx.what());
+        close();
+        return;
+      } catch (TException &x) {
+        fprintf(stderr, "TException: Server::process() %s\n", x.what());
+        close();     
+        return;
+      } catch (...) {
+        fprintf(stderr, "Server::process() unknown exception\n");
+        close();
+        return;
+      }
     }
 
+  case APP_WAIT_TASK:
+    // We have now finished processing a task and the result has been written
+    // into the outputTransport_, so we grab its contents and place them into
+    // the writeBuffer_ for actual writing by the libevent thread
+
     // Get the result of the operation
     outputTransport_->getBuffer(&writeBuffer_, &writeBufferSize_);
 
@@ -212,7 +294,7 @@
       setWrite();
 
       // Try to work the socket immediately
-      workSocket();
+      // workSocket();
 
       return;
     }
@@ -232,7 +314,7 @@
     appState_ = APP_SEND_RESULT;
 
     // Go to work on the socket right away, probably still writeable
-    workSocket();
+    // workSocket();
 
     return;
 
@@ -260,7 +342,7 @@
     setRead();
 
     // Try to work the socket right away
-    workSocket();
+    // workSocket();
 
     return;
 
@@ -283,7 +365,7 @@
     appState_ = APP_READ_REQUEST;
 
     // Work the socket right away
-    workSocket();
+    // workSocket();
 
     return;
 
@@ -315,13 +397,13 @@
    *
    * Prepares the event structure &event to be used in future calls to
    * event_add() and event_del().  The event will be prepared to call the
-   * event_handler using the 'sock' file descriptor to monitor events.
+   * eventHandler using the 'sock' file descriptor to monitor events.
    *
    * The events can be either EV_READ, EV_WRITE, or both, indicating
    * that an application can read or write from the file respectively without
    * blocking.
    *
-   * The event_handler will be called with the file descriptor that triggered
+   * The eventHandler will be called with the file descriptor that triggered
    * the event and the type of event which will be one of: EV_TIMEOUT,
    * EV_SIGNAL, EV_READ, EV_WRITE.
    *
@@ -330,7 +412,7 @@
    *
    * Once initialized, the &event struct can be used repeatedly with
    * event_add() and event_del() and does not need to be reinitialized unless
-   * the event_handler and/or the argument to it are to be changed.  However,
+   * the eventHandler and/or the argument to it are to be changed.  However,
    * when an ev structure has been added to libevent using event_add() the
    * structure must persist until the event occurs (assuming EV_PERSIST
    * is not set) or is removed using event_del().  You may not reuse the same
@@ -516,12 +598,12 @@
             this);
 
   // Add the event and start up the server
-  if (event_add(&serverEvent, 0) == -1) {
+  if (-1 == event_add(&serverEvent, 0)) {
     GlobalOutput("TNonblockingServer::serve(): coult not event_add");
     return;
   }
 
-  // Run libevent engine, never returns, invokes calls to event_handler
+  // Run libevent engine, never returns, invokes calls to eventHandler
   event_loop(0);
 }