Changed behaviour on publishing workflows (#5208)

Instead of repopulation the entire ActivityRegistry, only add the new workflow definition.

src/bundles/Elsa.ServerAndStudio.Web/Program.cs

@@ -59,7 +59,12 @@ services
             .UseWorkflowRuntime(runtime =>
             {
                 runtime.UseEntityFrameworkCore(ef => ef.UseSqlite(sqliteConnectionString));
-                runtime.UseMassTransitDispatcher();
+                
+                if (useMassTransit)
+                {
+                    runtime.UseMassTransitDispatcher();
+                }
+                
                 if (useProtoActor)
                 {
                     runtime.UseProtoActor(proto => proto.PersistenceProvider = _ =>

src/modules/Elsa.MassTransit/Consumers/WorkflowDefinitionEventsConsumer.cs

@@ -26,7 +26,10 @@ public class WorkflowDefinitionEventsConsumer(IActivityRegistryPopulator activit
     public Task Consume(ConsumeContext<WorkflowDefinitionDeleted> context) => RefreshAsync();
 
     /// <inheritdoc />
-    public Task Consume(ConsumeContext<WorkflowDefinitionPublished> context) => RefreshAsync();
+    public async Task Consume(ConsumeContext<WorkflowDefinitionPublished> context)
+    {
+        await activityRegistryPopulator.AddToRegistry(typeof(WorkflowDefinitionActivityProvider), context.Message.Id);
+    }
 
     /// <inheritdoc />
     public Task Consume(ConsumeContext<WorkflowDefinitionRetracted> context) => RefreshAsync();

src/modules/Elsa.Workflows.Management/Contracts/IActivityRegistryPopulator.cs

@@ -19,4 +19,12 @@ public interface IActivityRegistryPopulator
     /// <param name="providerType">The type of the provider.</param>
     /// <param name="cancellationToken">The cancellation token.</param>
     Task PopulateRegistryAsync(Type providerType, CancellationToken cancellationToken = default);
+
+    /// <summary>
+    /// Tries to add a workflow as an activity to the registry.
+    /// </summary>
+    /// <param name="providerType">The type of the activity provider.</param>
+    /// <param name="workflowDefinitionId">The ID of the workflow definition.</param>
+    /// <param name="cancellationToken">The cancellation token.</param>
+    Task AddToRegistry(Type providerType, string workflowDefinitionId, CancellationToken cancellationToken = default);
 }

src/modules/Elsa.Workflows.Management/Handlers/RefreshActivityRegistryHandler.cs

@@ -22,7 +22,10 @@ public class RefreshActivityRegistryHandler(IActivityRegistryPopulator activityR
     INotificationHandler<WorkflowDefinitionVersionsDeleted>
 {
     /// <inheritdoc />
-    public async Task HandleAsync(WorkflowDefinitionPublished notification, CancellationToken cancellationToken) => await RefreshAsync(cancellationToken);
+    public async Task HandleAsync(WorkflowDefinitionPublished notification, CancellationToken cancellationToken)
+    {
+        await activityRegistryPopulator.AddToRegistry(typeof(WorkflowDefinitionActivityProvider), notification.WorkflowDefinition.Id);
+    }
 
     /// <inheritdoc />
     public async Task HandleAsync(WorkflowDefinitionRetracted notification, CancellationToken cancellationToken) => await RefreshAsync(cancellationToken);

src/modules/Elsa.Workflows.Management/Services/ActivityRegistryPopulator.cs

@@ -37,6 +37,18 @@ public class ActivityRegistryPopulator : IActivityRegistryPopulator
         await PopulateRegistryAsync(provider, cancellationToken);
     }
 
+    /// <inheritdoc />
+    public async Task AddToRegistry(Type providerType, string workflowDefinitionVersionId, CancellationToken cancellationToken = default)
+    {
+        var provider = _providers.First(x => x.GetType() == providerType);
+        var descriptors = await provider.GetDescriptorsAsync(cancellationToken);
+        var descriptorToAdd = descriptors
+            .SingleOrDefault(d => d.CustomProperties.TryGetValue("WorkflowDefinitionVersionId", out var val) && val.ToString() == workflowDefinitionVersionId);
+        
+        if (descriptorToAdd is not null)
+            _registry.Add(providerType, descriptorToAdd!);
+    }
+
     private async Task PopulateRegistryAsync(IActivityProvider provider, CancellationToken cancellationToken = default)
     {
         var descriptors = await provider.GetDescriptorsAsync(cancellationToken);