Added a mechanism to send error to the client when the server has an exception

castor/tape/tapeserver/daemon/TapeMessageHandler.cpp

@@ -209,7 +209,9 @@ void castor::tape::tapeserver::daemon::TapeMessageHandler::dispatchEvent(
   }
 }
 
-
+//------------------------------------------------------------------------------
+// dealWith
+//------------------------------------------------------------------------------
 void castor::tape::tapeserver::daemon::TapeMessageHandler::dealWith(
 const castor::messages::Header& header, const castor::messages::Heartbeat& body){
   
@@ -229,9 +231,13 @@ const castor::messages::NotifyDriveBeforeMountStarted& body){
     legacymsg::VmgrTapeInfoMsgBody tapeInfo;
     m_vmgr.queryTape(body.vid(), tapeInfo);
     // If the client is the tape gateway and the volume is not marked as BUSY
-    if(body.clienttype() == castor::messages::NotifyDriveBeforeMountStarted::CLIENT_TYPE_GATEWAY && !(tapeInfo.status & TAPE_BUSY)) {
+    if(body.clienttype() == castor::messages::NotifyDriveBeforeMountStarted::CLIENT_TYPE_GATEWAY 
+            && !(tapeInfo.status & TAPE_BUSY)) {
       castor::exception::Exception ex;
       ex.getMessage() << "The tape gateway is the client and the tape to be mounted is not BUSY: vid=" << body.vid();
+      
+      //send an error to the client
+      sendErrorReplyToClient(ex);
       throw ex;
     }
     
@@ -243,13 +249,18 @@ const castor::messages::NotifyDriveBeforeMountStarted& body){
     header.set_bodyhashvalue(castor::messages::computeSHA1Base64(body));
     header.set_bodysignature("PIPO");
     
+    //send the number of files on the tape to the client
     castor::messages::sendMessage(m_socket,header,ZMQ_SNDMORE);
     castor::messages::sendMessage(m_socket,body);
   } else {
+    //we were not event in castor::messages::TAPE_MODE_READWRITE mpde
+    //so send empty answer
     sendSuccessReplyToClient();
   }
 }
-
+//------------------------------------------------------------------------------
+// dealWith
+//------------------------------------------------------------------------------
 void castor::tape::tapeserver::daemon::TapeMessageHandler::dealWith(
 const castor::messages::Header& header, 
 const castor::messages::NotifyDriveTapeMounted& body){
@@ -259,33 +270,57 @@ const castor::messages::NotifyDriveTapeMounted& body){
   const utils::DriveConfig &driveConfig = drive->getConfig();
     
   const std::string vid = body.vid();
-  switch(body.mode()) {
-    case castor::messages::TAPE_MODE_READ:
-      m_vmgr.tapeMountedForRead(vid);
-      break;
-    case castor::messages::TAPE_MODE_READWRITE:
-      m_vmgr.tapeMountedForWrite(vid);
-      break;
-    case castor::messages::TAPE_MODE_DUMP:
-      m_vmgr.tapeMountedForRead(vid);
-      break;
-    case castor::messages::TAPE_MODE_NONE:
-      break;
-    default:
-      castor::exception::Exception ex;
-      ex.getMessage() << "Unknown tape mode: " << body.mode();
-      throw ex;
+  try
+  {
+    switch(body.mode()) {
+      case castor::messages::TAPE_MODE_READ:
+        m_vmgr.tapeMountedForRead(vid);
+        break;
+      case castor::messages::TAPE_MODE_READWRITE:
+        m_vmgr.tapeMountedForWrite(vid);
+        break;
+      case castor::messages::TAPE_MODE_DUMP:
+        m_vmgr.tapeMountedForRead(vid);
+        break;
+      case castor::messages::TAPE_MODE_NONE:
+        break;
+      default:
+        castor::exception::Exception ex;
+        ex.getMessage() << "Unknown tape mode: " << body.mode();
+        throw ex;
+    }
+    m_vdqm.tapeMounted(m_hostName, body.unitname(), driveConfig.dgn, body.vid(),
+            drive->getSessionPid());
+  }catch(const castor::exception::Exception& ex){
+    sendErrorReplyToClient(ex);
+    throw;
   }
-  m_vdqm.tapeMounted(m_hostName, body.unitname(), driveConfig.dgn, body.vid(),
-    drive->getSessionPid());
   
   sendSuccessReplyToClient();
 }
-
+//------------------------------------------------------------------------------
+// sendSuccessReplyToClient
+//------------------------------------------------------------------------------
 void castor::tape::tapeserver::daemon::TapeMessageHandler::sendSuccessReplyToClient(){
     castor::messages::ReturnValue body;
-    body.set_returnvalue(0);
-    body.set_message("");
+    sendReplyToClient(0,"");
+}
+//------------------------------------------------------------------------------
+// sendErrorReplyToClient
+//------------------------------------------------------------------------------
+void castor::tape::tapeserver::daemon::TapeMessageHandler::
+sendErrorReplyToClient(const castor::exception::Exception& ex){
+  //any positive value will trigger an exception in the client side
+  sendReplyToClient(ex.code(),ex.getMessageValue());
+}
+//------------------------------------------------------------------------------
+// sendReplyToClient
+//------------------------------------------------------------------------------
+void castor::tape::tapeserver::daemon::TapeMessageHandler::
+sendReplyToClient(int returnValue,const std::string& msg){
+    castor::messages::ReturnValue body;
+    body.set_returnvalue(returnValue);
+    body.set_message(msg);
   
     castor::messages::Header header = castor::messages::preFillHeader();
     header.set_reqtype(messages::reqType::ReturnValue);
@@ -294,4 +329,4 @@ void castor::tape::tapeserver::daemon::TapeMessageHandler::sendSuccessReplyToCli
 
     castor::messages::sendMessage(m_socket,header,ZMQ_SNDMORE);
     castor::messages::sendMessage(m_socket,body);
-}
+}
\ No newline at end of file

castor/tape/tapeserver/daemon/TapeMessageHandler.hpp

@@ -93,8 +93,30 @@ public:
   bool handleEvent(const zmq_pollitem_t &fd);
   
 private:
+  /**
+   *  Send to the client a ReturnValue(0,"")
+   */
   void sendSuccessReplyToClient();
+  /**
+   * Send to the client a ReturnValue(ex.code(),ex.getGetMessageValue())
+   * @param e
+   */
+  void sendErrorReplyToClient(const castor::exception::Exception& e);
+
+  /**
+   * Send to the client a ReturnValue Message with the given parameters
+   * @param returnValue the interger value to send (0 = everything ok, 
+   * positive integer will trigger an exception
+   * @param msg The string to display (should be empty if returnValue=0)
+   */
+  void sendReplyToClient(int returnValue,const std::string& msg);
   
+  /**
+   * Will try to parse a message of type T into msg from the data which are 
+   * within blob
+   * @param msg
+   * @param blob
+   */
   template <class T> void unserialize(T& msg, tape::utils::ZmqMsg& blob){
     std::string logMessage="Cant parse " ;
     logMessage+=castor::utils::demangledNameOf(msg)+" from binary data. Wrong body";
@@ -126,7 +148,7 @@ private:
   const std::string m_hostName;
   
   /** 
-   * Reference to the VdqmProxy, allowing reporting of the drive status. It
+   * Reference to the VdqmProxy, allowing reporting of the drive status. It 
    * will be used by the StatusReporter 
    */
   castor::legacymsg::VdqmProxy & m_vdqm;
@@ -137,8 +159,17 @@ private:
    */
   castor::legacymsg::VmgrProxy & m_vmgr;
   
+  /**
+   * Make sure the  zmq_pollitem_t's socket is the same as m_socket
+   * Throw an exception if it is not the case
+   * @param fd the poll item 
+   */
   void checkSocket(const zmq_pollitem_t &fd);
   
+  /**
+   * Call the right dealWith according to header.reqType()
+   * @param header
+   */
   void dispatchEvent(castor::messages::Header& header);
   
   void dealWith(const castor::messages::Header&,
@@ -147,12 +178,12 @@ private:
   void dealWith(const castor::messages::Header& header, 
      const castor::messages::NotifyDriveBeforeMountStarted& body);
 
-void dealWith(const castor::messages::Header& header,
+  void dealWith(const castor::messages::Header& header,
      const castor::messages::NotifyDriveTapeMounted& body); 
 
   /**
-   * Unserialise the blob and check the header
-   * @param headerBlob
+   * Unserialize the blob and check the header
+   * @param headerBlob The blob from the header
    */
   castor::messages::Header buildHeader(tape::utils::ZmqMsg& headerBlob);
 }; // class TapeMessageHandler