fix: use null instead of empty string to make it clearer what's happening

Fixed some issues with log messages that were not formatted correctly for Serilog.

src/PepperDash.Essentials.Core/Routing/Extensions.cs

@@ -141,23 +141,28 @@ namespace PepperDash.Essentials.Core
         /// <param name="destination"></param>       
         public static void ReleaseRoute(this IRoutingInputs destination, string inputPortKey)
         {
-
-            Debug.LogMessage(LogEventLevel.Information, "Release route for {inputPortKey}", destination, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
-
-            if (RouteRequests.TryGetValue(destination.Key, out RouteRequest existingRequest) && destination is IWarmingCooling)
+            try
             {
-                var coolingDevice = destination as IWarmingCooling;
+                Debug.LogMessage(LogEventLevel.Information, "Release route for '{destination}':'{inputPortKey}'", destination?.Key ?? null, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
 
-                coolingDevice.IsCoolingDownFeedback.OutputChange -= existingRequest.HandleCooldown;
-            }
+                if (RouteRequests.TryGetValue(destination.Key, out RouteRequest existingRequest) && destination is IWarmingCooling)
+                {
+                    var coolingDevice = destination as IWarmingCooling;
 
-            RouteRequests.Remove(destination.Key);
+                    coolingDevice.IsCoolingDownFeedback.OutputChange -= existingRequest.HandleCooldown;
+                }
 
-            var current = RouteDescriptorCollection.DefaultCollection.RemoveRouteDescriptor(destination, inputPortKey);
-            if (current != null)
+                RouteRequests.Remove(destination.Key);
+
+                var current = RouteDescriptorCollection.DefaultCollection.RemoveRouteDescriptor(destination, inputPortKey);
+                if (current != null)
+                {
+                    Debug.LogMessage(LogEventLevel.Information, "Releasing current route: {0}", destination, current.Source.Key);
+                    current.ReleaseRoutes();
+                }
+            } catch (Exception ex)
             {
-                Debug.LogMessage(LogEventLevel.Debug, "Releasing current route: {0}", destination, current.Source.Key);
-                current.ReleaseRoutes();
+                Debug.LogMessage(ex, "Exception releasing route for '{destination}':'{inputPortKey}'",null, destination?.Key ?? null, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
             }
         }
 
@@ -179,7 +184,8 @@ namespace PepperDash.Essentials.Core
                 if (!destination.GetRouteToSource(source, null, null, signalType, 0, singleTypeRouteDescriptor, destinationPort, sourcePort))
                     singleTypeRouteDescriptor = null;
 
-                foreach (var route in singleTypeRouteDescriptor.Routes)
+                var routes = singleTypeRouteDescriptor?.Routes ?? new List<RouteSwitchDescriptor>();
+                foreach (var route in routes)
                 {
                     Debug.LogMessage(LogEventLevel.Verbose, "Route for device: {route}", destination, route.ToString());
                 }

src/PepperDash.Essentials.Core/Routing/RouteDescriptorCollection.cs

@@ -53,14 +53,14 @@ namespace PepperDash.Essentials.Core
         /// <returns>null if no RouteDescriptor for a destination exists</returns>
         public RouteDescriptor GetRouteDescriptorForDestination(IRoutingInputs destination)
         {
-            Debug.LogMessage(LogEventLevel.Debug, "Getting route descriptor", destination);
+            Debug.LogMessage(LogEventLevel.Information, "Getting route descriptor for '{destination}'", destination?.Key ?? null);
 
             return RouteDescriptors.FirstOrDefault(rd => rd.Destination == destination);
         }
 
         public RouteDescriptor GetRouteDescriptorForDestinationAndInputPort(IRoutingInputs destination, string inputPortKey)
         {
-            Debug.LogMessage(LogEventLevel.Debug, "Getting route descriptor for {inputPortKey}", destination, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
+            Debug.LogMessage(LogEventLevel.Information, "Getting route descriptor for '{destination}':'{inputPortKey}'", destination?.Key ?? null, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
             return RouteDescriptors.FirstOrDefault(rd => rd.Destination == destination && rd.InputPort != null && rd.InputPort.Key == inputPortKey);
         }
 
@@ -70,7 +70,7 @@ namespace PepperDash.Essentials.Core
         /// </summary>
         public RouteDescriptor RemoveRouteDescriptor(IRoutingInputs destination, string inputPortKey = "")
         {
-            Debug.LogMessage(LogEventLevel.Debug, "Removing route descriptor for {inputPortKey}", destination, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
+            Debug.LogMessage(LogEventLevel.Information, "Removing route descriptor for '{destination}':'{inputPortKey}'", destination.Key ?? null, string.IsNullOrEmpty(inputPortKey) ? "auto" : inputPortKey);
 
             var descr = string.IsNullOrEmpty(inputPortKey) 
                 ? GetRouteDescriptorForDestination(destination)
@@ -78,7 +78,7 @@ namespace PepperDash.Essentials.Core
             if (descr != null)
                 RouteDescriptors.Remove(descr);
 
-            Debug.LogMessage(LogEventLevel.Debug, "Found route descriptor {routeDescriptor}", destination, descr);
+            Debug.LogMessage(LogEventLevel.Information, "Found route descriptor {routeDescriptor}", destination, descr);
 
             return descr;
         }