Enable backward compatibility by enabling empty isolation key (#91) (#93)

Co-authored-by: Benjamin SPETH <bspeth@ecovadis.com>

Author: benspeth

src/Ev.ServiceBus.Abstractions/Configuration/ServiceBusSettings.cs

@@ -28,7 +28,7 @@ public sealed class ServiceBusSettings
     /// </summary>
     public bool UseIsolation { get; set; } = false;
     /// <summary>
-    /// Key that is used to deremine if this running instance should receive and complete or abandon a message
+    /// Key that is used to determine if this running instance should receive and complete or abandon a message
     /// </summary>
     public string? IsolationKey { get; set; } = null;
 

src/Ev.ServiceBus/Reception/MessageReceptionHandler.cs

@@ -50,7 +50,7 @@ public async Task HandleMessageAsync(MessageContext context)
             if (_serviceBusOptions.Settings.UseIsolation)
             {
                 var expectedIsolationKey = _serviceBusOptions.Settings.IsolationKey;
-                var receivedIsolationKey = context.IsolationKey;
+                var receivedIsolationKey = context.IsolationKey ?? string.Empty;
                 if (receivedIsolationKey != expectedIsolationKey)
                 {
                     _logger.IgnoreMessage(expectedIsolationKey, receivedIsolationKey);

src/Ev.ServiceBus/ServiceBusEngine.cs

@@ -51,7 +51,7 @@ public async Task StartAll()
                 _serviceBusEngineLogger.FailedToConnectToServiceBus(ex);
             }
         }
-        if (settings.UseIsolation && string.IsNullOrEmpty(settings.IsolationKey))
+        if (settings.UseIsolation && settings.IsolationKey == null)
         {
             throw new Exception("Isolation key must be set when isolation is enabled");
         }