PVA: TCP thread keeps trying to connect

Author: kasemir

core/pva/src/main/java/org/epics/pva/client/ClientTCPHandler.java

@@ -131,11 +131,19 @@ public ClientTCPHandler(final PVAClient client, final InetSocketAddress address,
     }
 
     @Override
-    protected void initializeSocket() throws Exception
+    protected boolean initializeSocket()
     {
-        socket = SecureSockets.createClientSocket(server_address, tls);
-        socket.setTcpNoDelay(true);
-        socket.setKeepAlive(true);
+        try
+        {
+            socket = SecureSockets.createClientSocket(server_address, tls);
+            socket.setTcpNoDelay(true);
+            socket.setKeepAlive(true);
+        }
+        catch (Exception ex)
+        {   
+            logger.log(Level.WARNING, "PVA client cannot connect to " + server_address, ex);
+            return false;
+        }
 
         // For TLS, check if the socket has a name that's used to authenticate
         x509_name = tls ? SecureSockets.getPrincipalCN(((SSLSocket) socket).getSession().getLocalPrincipal()) : null;
@@ -145,6 +153,8 @@ protected void initializeSocket() throws Exception
         last_life_sign = last_message_sent = System.currentTimeMillis();
         final long period = Math.max(1, PVASettings.EPICS_PVA_CONN_TMO * 1000L / 30 * 3);
         alive_check = timer.scheduleWithFixedDelay(this::checkResponsiveness, period, period, TimeUnit.MILLISECONDS);
+
+        return true;
     }
 
     /** @return Client context */

core/pva/src/main/java/org/epics/pva/common/TCPHandler.java

@@ -138,9 +138,11 @@ public TCPHandler(final boolean client_mode)
     /** Initialize the {@link #socket}. Called by receiver.
      *
      *  Server received socket from `accept` during construction and this may be a NOP.
-     *  Client will have to create socket and connect to server's address in here
+     *  Client will have to create socket and connect to server's address in here.
+     *
+     *  @return Success?
      */
-    abstract protected void initializeSocket() throws Exception;
+    abstract protected boolean initializeSocket();
 
     /** Start receiving data
      *  To be called by Client/ServerTCPHandler when fully constructed
@@ -267,10 +269,20 @@ protected void send(final ByteBuffer buffer) throws Exception
     /** Receiver */
     private Void receiver()
     {
+        // Establish connection
+        Thread.currentThread().setName("TCP receiver");
+        while (! initializeSocket())
+            try
+            {   // Delay for (another) connection timeout, at least 1 sec
+                Thread.sleep(Math.max(1, PVASettings.EPICS_PVA_TCP_SOCKET_TMO) * 1000);
+            }
+            catch (Exception ignore)
+            {
+                // NOP
+            }
+        // Listen on the connection
         try
         {
-            Thread.currentThread().setName("TCP receiver");
-            initializeSocket();
             Thread.currentThread().setName("TCP receiver " + socket.getLocalSocketAddress());
             logger.log(Level.FINER, () -> Thread.currentThread().getName() + " started for " + socket.getRemoteSocketAddress());
             logger.log(Level.FINER, "Native byte order " + receive_buffer.order());

core/pva/src/main/java/org/epics/pva/server/ServerTCPHandler.java

@@ -116,9 +116,10 @@ public ServerTCPHandler(final PVAServer server, final Socket client, final TLSHa
     }
 
     @Override
-    protected void initializeSocket() throws Exception
+    protected boolean initializeSocket()
     {
         // Nothing to do, received client socket on construction
+        return true;
     }
 
     PVAServer getServer()