[#3721] addressed review comments

ChangeLog

@@ -2,7 +2,7 @@
 	The kea-dhcp4, kea-dhcp6 and kea-dhcp-ddns servers now support
 	multiple http/https connections. The can be configured in the
 	"control-sockets" list.
-	(Gitlab #3082)
+	(Gitlab #3082, #3721)
 
 2315.	[func]		razvan
 	Kea can now load hook libraries specifying only the binary name.

src/bin/agent/ca_process.cc

@@ -152,6 +152,7 @@ CtrlAgentProcess::configure(isc::data::ConstElementPtr config_set,
                         .arg(server_port);
                 }
             }
+            // If the connection can be reused, mark it as usable.
             it->second->usable_ = true;
         } else {
 
@@ -210,8 +211,12 @@ CtrlAgentProcess::configure(isc::data::ConstElementPtr config_set,
         auto copy = sockets_;
         for (auto const& data : copy) {
             if (data.second->usable_) {
+                // If the connection can be used (just created) or reused, keep it
+                // in the list and clear the flag. It will be marked again on next
+                // configuration event if needed.
                 data.second->usable_ = false;
             } else {
+                // If the connection can not be reused, stop it and remove it from the list.
                 data.second->listener_->stop();
                 auto it = sockets_.find(std::make_pair(data.second->config_->getHttpHost(),
                                                        data.second->config_->getHttpPort()));

src/lib/config/http_command_mgr.cc

@@ -102,8 +102,12 @@ HttpCommandMgrImpl::openCommandSockets(const isc::data::ConstElementPtr config)
     auto copy = sockets_;
     for (auto const& data : copy) {
         if (data.second->usable_) {
+            // If the connection can be used (just created) or reused, keep it
+            // in the list and clear the flag. It will be marked again on next
+            // configuration event if needed.
             data.second->usable_ = false;
         } else {
+            // If the connection can not be reused, stop it and remove it from the list.
             closeCommandSocket(data.second, true);
         }
     }
@@ -133,6 +137,7 @@ HttpCommandMgrImpl::openCommandSocket(const isc::data::ConstElementPtr config) {
             it->second->config_->setAuthConfig(cmd_config->getAuthConfig());
             it->second->config_->setEmulateAgentResponse(cmd_config->getEmulateAgentResponse());
         }
+        // If the connection can be reused, mark it as usable.
         it->second->usable_ = true;
         return;
     }

src/lib/config/unix_command_mgr.cc

@@ -574,8 +574,12 @@ UnixCommandMgrImpl::openCommandSockets(const isc::data::ConstElementPtr config)
     auto copy = sockets_;
     for (auto const& data : copy) {
         if (data.second->usable_) {
+            // If the connection can be used (just created) or reused, keep it
+            // in the list and clear the flag. It will be marked again on next
+            // configuration event if needed.
             data.second->usable_ = false;
         } else {
+            // If the connection can not be reused, stop it and remove it from the list.
             closeCommandSocket(data.second);
         }
     }
@@ -592,6 +596,7 @@ UnixCommandMgrImpl::openCommandSocket(const isc::data::ConstElementPtr config) {
     // Search for the specific connection and reuse the existing one if found.
     auto it = sockets_.find(cmd_config->getSocketName());
     if (it != sockets_.end()) {
+        // If the connection can be reused, mark it as usable.
         it->second->usable_ = true;
         return;
     }