AcsProxyZmq now connects on demand

mediachanger/AcsProxyZmq.cpp

@@ -169,9 +169,8 @@ Frame createAcsForceDismountTapeFrame(const std::string &vid, const AcsLibrarySl
 // constructor
 //------------------------------------------------------------------------------
 AcsProxyZmq::AcsProxyZmq(void *const zmqContext, const unsigned short serverPort) throw():
-  m_serverPort(serverPort),
-  m_serverSocket(zmqContext, ZMQ_REQ) {
-  connectZmqSocketToLocalhost(m_serverSocket, serverPort);
+  m_zmqContext(zmqContext),
+  m_serverPort(serverPort) {
 }
 
 //------------------------------------------------------------------------------
@@ -182,10 +181,10 @@ void AcsProxyZmq::mountTapeReadOnly(const std::string &vid, const LibrarySlot &l
   
   try {
     const Frame rqst = createAcsMountTapeReadOnlyFrame(vid, dynamic_cast<const AcsLibrarySlot&>(librarySlot));
-    sendFrame(m_serverSocket, rqst);
+    sendFrame(serverSocketInstance(), rqst);
 
     MediaChangerReturnValue reply;
-    recvTapeReplyOrEx(m_serverSocket, reply);
+    recvTapeReplyOrEx(serverSocketInstance(), reply);
     if(0 != reply.value()) {
       // Should never get here
       cta::exception::Exception ex;
@@ -210,10 +209,10 @@ void AcsProxyZmq::mountTapeReadWrite(const std::string &vid, const LibrarySlot &
   
   try {
     const Frame rqst = createAcsMountTapeReadWriteFrame(vid, dynamic_cast<const AcsLibrarySlot&>(librarySlot));
-    sendFrame(m_serverSocket, rqst);
+    sendFrame(serverSocketInstance(), rqst);
 
     MediaChangerReturnValue reply;
-    recvTapeReplyOrEx(m_serverSocket, reply);
+    recvTapeReplyOrEx(serverSocketInstance(), reply);
     if(0 != reply.value()) {
       // Should never get here
       cta::exception::Exception ex;
@@ -238,10 +237,10 @@ void AcsProxyZmq::dismountTape(const std::string &vid, const LibrarySlot &librar
   
   try {
     const Frame rqst = createAcsDismountTapeFrame(vid, dynamic_cast<const AcsLibrarySlot&>(librarySlot));
-    sendFrame(m_serverSocket, rqst);
+    sendFrame(serverSocketInstance(), rqst);
 
     MediaChangerReturnValue reply;
-    recvTapeReplyOrEx(m_serverSocket, reply);
+    recvTapeReplyOrEx(serverSocketInstance(), reply);
     if(0 != reply.value()) {
       // Should never get here
       cta::exception::Exception ex;
@@ -266,10 +265,10 @@ void AcsProxyZmq::forceDismountTape(const std::string &vid, const LibrarySlot &l
   
   try {
     const Frame rqst = createAcsForceDismountTapeFrame(vid, dynamic_cast<const AcsLibrarySlot&>(librarySlot));
-    sendFrame(m_serverSocket, rqst);
+    sendFrame(serverSocketInstance(), rqst);
 
     MediaChangerReturnValue reply;
-    recvTapeReplyOrEx(m_serverSocket, reply);
+    recvTapeReplyOrEx(serverSocketInstance(), reply);
     if(0 != reply.value()) {
       // Should never get here
       cta::exception::Exception ex;
@@ -286,5 +285,16 @@ void AcsProxyZmq::forceDismountTape(const std::string &vid, const LibrarySlot &l
   }
 }
 
+//------------------------------------------------------------------------------
+// serverSocketInstance
+//------------------------------------------------------------------------------
+ZmqSocketMT &AcsProxyZmq::serverSocketInstance() {
+  if(nullptr == m_serverSocket) {
+    m_serverSocket.reset(new ZmqSocketMT(m_zmqContext, ZMQ_REQ));
+    connectZmqSocketToLocalhost(*m_serverSocket, m_serverPort);
+  }
+  return *m_serverSocket;
+}
+
 } // namespace mediachanger
 } // namespace cta

mediachanger/AcsProxyZmq.hpp

@@ -22,6 +22,7 @@
 #include "mediachanger/MediaChangerProxy.hpp"
 #include "mediachanger/ZmqSocketMT.hpp"
 
+#include <memory>
 #include <mutex>
 
 namespace cta {
@@ -80,6 +81,11 @@ public:
   void forceDismountTape(const std::string &vid, const LibrarySlot &librarySlot) override;
 
 private:
+
+  /**
+   * The ZMQ context.
+   */
+  void *m_zmqContext;
   
   /**
    * Mutex used to implement a critical section around the enclosed
@@ -94,9 +100,21 @@ private:
   const unsigned short m_serverPort;
 
   /**
-   * Socket connecting this proxy the daemon it represents.
+   * Socket connecting this proxy to the daemon it represents.
+   */
+  std::unique_ptr<ZmqSocketMT> m_serverSocket;
+
+  /**
+   * Returns the socket instance connecting this proxy to the daemon it
+   * represents.  This method instantiates a socket and connects it if
+   * a socket does not already exist.
+   *
+   * Please note that a lock MUST be taken on m_mutex before calling this
+   * method.
+   *
+   * @return The socket connecting this proxy the daemon it represents.
    */
-  ZmqSocketMT m_serverSocket;
+  ZmqSocketMT &serverSocketInstance();
 
 }; // class AcsProxyZmq