Workflow tutorials C#

tutorials/workflow/csharp/challenges-tips/DeterministicWorkflow.cs

@@ -0,0 +1,48 @@
+using System;
+using Dapr.Workflow;
+
+namespace WorkflowApp
+{
+    public class NonDeterministicWorkflow : Workflow<string, string>
+    {
+        public override async Task<string> RunAsync(WorkflowContext context, string orderItem)
+        {
+            // Do not use non-deterministic operations in a workflow!
+            // These operations will create a new value every time the
+            // workflow is replayed.
+            var orderId = Guid.NewGuid().ToString();
+            var orderDate = DateTime.UtcNow;
+
+            var idResult = await context.CallActivityAsync<string>(
+                "SubmitId",
+                orderId);
+
+            await context.CallActivityAsync<string>(
+                "SubmitDate",
+                orderDate);
+
+            return idResult;
+        }
+    }
+
+    public class DeterministicWorkflow : Workflow<string, string>
+    {
+        public override async Task<string> RunAsync(WorkflowContext context, string orderItem)
+        {
+            // Do use these deterministic methods and properties on the WorkflowContext instead.
+            // These operations create the same value when the workflow is replayed.
+            var orderId = context.NewGuid().ToString();
+            var orderDate = context.CurrentUtcDateTime;
+
+            var idResult = await context.CallActivityAsync<string>(
+                "SubmitId",
+                orderId);
+
+            await context.CallActivityAsync<string>(
+                "SubmitDate",
+                orderDate);
+
+            return idResult;
+        }
+    }
+}

tutorials/workflow/csharp/challenges-tips/IdempotentActivity.cs

@@ -0,0 +1,19 @@
+using Dapr.Client;
+using Dapr.Workflow;
+
+namespace WorkflowApp
+{
+    public class IdempotentActivity : WorkflowActivity<string, string>
+    {
+        public override async Task<InventoryResult> RunAsync(WorkflowActivityContext context, OrderItem orderItem)
+        {
+            // Beware of non-idempotent operations in an activity.
+            // Dapr Workflow guarantees at-least-once execution of activities, so activities might be executed more than once.
+            // For instance, can you insert a record to a database twice without side effects?
+            //      var insertSql = $"INSERT INTO Orders (Id, Description, UnitPrice, Quantity) VALUES ('{orderItem.Id}', '{orderItem.Description}', {orderItem.UnitPrice}, {orderItem.Quantity})";
+            // It's best to perform a check if an record already exists before inserting it.
+        }
+    }
+
+    record OrderItem(string Id, string Description, double UnitPrice, int Quantity);
+}

tutorials/workflow/csharp/challenges-tips/PayloadSizeWorkflow.cs

@@ -0,0 +1,44 @@
+using Dapr.Workflow;
+
+namespace WorkflowApp
+{
+    public class LargePayloadSizeWorkflow : Workflow<string, LargeDocument>
+    {
+        public override async Task<LargeDocument> RunAsync(WorkflowContext context, string id)
+        {
+            // Do not pass large payloads between activities.
+            // They are stored in the Dapr state store twice, one as output argument 
+            // for GetDocument, and once as input argument for UpdateDocument.
+            var document = await context.CallActivityAsync<LargeDocument>(
+                "GetDocument",
+                id);
+
+            var updatedDocument = await context.CallActivityAsync<LargeDocument>(
+                "UpdateDocument",
+                document);
+
+            // More activities to process the updated document...
+
+            return updatedDocument;
+        }
+    }
+
+
+    public class SmallPayloadSizeWorkflow : Workflow<string, string>
+    {
+        public override async Task<string> RunAsync(WorkflowContext context, string id)
+        {
+            // Do pass small payloads between activities, preferably IDs only, or objects that are quick to (de)serialize in large volumes.
+            // Combine multiple actions, such as document retrieval and update, into a single activity.
+            var documentId = await context.CallActivityAsync<string>(
+                "GetAndUpdateDocument",
+                id);
+
+            // More activities to process the updated document...
+
+            return documentId;
+        }
+    }
+
+    public record LargeDocument(string Id, object Data);
+}

tutorials/workflow/csharp/challenges-tips/VersioningWorkflow.cs

@@ -0,0 +1,42 @@
+using Dapr.Workflow;
+
+namespace WorkflowApp
+{
+    public class VersioningWorkflow1 : Workflow<string, int>
+    {
+        public override async Task<int> RunAsync(WorkflowContext context, string orderItem)
+        {
+            int resultA = await context.CallActivityAsync<int>(
+                "ActivityA",
+                orderItem);
+
+            int resultB = await context.CallActivityAsync<int>(
+                "ActivityB",
+                orderItem);
+
+            return resultA + resultB;
+        }
+    }
+
+    public class VersioningWorkflow2 : Workflow<string, int>
+    {
+        public override async Task<int> RunAsync(WorkflowContext context, string orderItem)
+        {
+            int resultA = await context.CallActivityAsync<int>(
+                "ActivityA",
+                orderItem);
+
+            // The input for ActivityB has changed from orderItem (string) to resultA (int).
+            // If there are in-flight workflows that were started with the previous version
+            // of this workflow, but have not yet completed, these will fail when the new version 
+            // of the workflow is deployed, since the parameters do not match with the persisted state.
+            // It is recommended to version workflows by creating a new workflow class with a new name:
+            // {workflowname}v1 -> {workflowname}v2
+            int resultB = await context.CallActivityAsync<int>(
+                "ActivityB",
+                resultA);
+
+            return resultA + resultB;
+        }
+    }
+}

tutorials/workflow/csharp/workflow-management/README.md

@@ -11,6 +11,10 @@ This tutorial demonstrates the various APIs to manage a workflow instance, these
 
 For more information on workflow management, see the [Dapr docs](https://docs.dapr.io/developing-applications/building-blocks/workflow/howto-manage-workflow/).
 
+## Inspect the code
+
+Open the `Program.cs` file in the `tutorials/workflow/csharp/child-workflows/WorkflowManagement` folder. This file contains the endpoint definitions that use the workflow management API. The workflow that is being managed is named `NeverEndingWorkflow` and will keep running once it's started.
+
 ## Run the tutorial
 
 1. Use a terminal to navigate to the `tutorials/workflow/csharp/workflow-management` folder.