Handle publish errors properly in PersistentQueueMessageSender. Create a connection descriptor store to handle all the message delivery errors and to avoid

duplicating error handling code (i.e. the connection descriptors map is null, the connection descriptor does not exist, etc).

broker/src/main/java/io/moquette/spi/impl/Qos2PublishHandler.java

@@ -1,7 +1,7 @@
 package io.moquette.spi.impl;
 
 import io.moquette.parser.proto.messages.*;
-import io.moquette.server.ConnectionDescriptor;
+import io.moquette.server.ConnectionDescriptorStore;
 import io.moquette.server.netty.NettyUtils;
 import io.moquette.spi.ClientSession;
 import io.moquette.spi.IMessagesStore;
@@ -15,7 +15,6 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.List;
-import java.util.concurrent.ConcurrentMap;
 
 import static io.moquette.spi.impl.ProtocolProcessor.asStoredMessage;
 
@@ -27,14 +26,14 @@ class Qos2PublishHandler {
     private final SubscriptionsStore subscriptions;
     private final IMessagesStore m_messagesStore;
     private final BrokerInterceptor m_interceptor;
-    private final ConcurrentMap<String, ConnectionDescriptor> connectionDescriptors;
+    private final ConnectionDescriptorStore connectionDescriptors;
     private final ISessionsStore m_sessionsStore;
     private final String brokerPort;
     private final MessagesPublisher publisher;
 
     public Qos2PublishHandler(IAuthorizator authorizator, SubscriptionsStore subscriptions,
                               IMessagesStore messagesStore, BrokerInterceptor interceptor,
-                              ConcurrentMap<String, ConnectionDescriptor> connectionDescriptors,
+                              ConnectionDescriptorStore connectionDescriptors,
                               ISessionsStore sessionsStore, String brokerPort, MessagesPublisher messagesPublisher) {
         this.m_authorizator = authorizator;
         this.subscriptions = subscriptions;
@@ -122,13 +121,13 @@ class Qos2PublishHandler {
         LOG.trace("PUB <--PUBREC-- SRV sendPubRec invoked for clientID {} with messageID {}", clientID, messageID);
         PubRecMessage pubRecMessage = new PubRecMessage();
         pubRecMessage.setMessageID(messageID);
-        connectionDescriptors.get(clientID).channel.writeAndFlush(pubRecMessage);
+        connectionDescriptors.sendMessage(pubRecMessage,messageID, clientID);
     }
 
     private void sendPubComp(String clientID, int messageID) {
         LOG.debug("PUB <--PUBCOMP-- SRV sendPubComp invoked for clientID {} ad messageID {}", clientID, messageID);
         PubCompMessage pubCompMessage = new PubCompMessage();
         pubCompMessage.setMessageID(messageID);
-        connectionDescriptors.get(clientID).channel.writeAndFlush(pubCompMessage);
+        connectionDescriptors.sendMessage(pubCompMessage, messageID, clientID);
     }
 }