.NET: [Feature Branch] Add Human In the Loop support for durable workflows

dotnet/agent-framework-dotnet.slnx

@@ -55,10 +55,12 @@
     <Project Path="samples/Durable/Workflow/ConsoleApps/05_WorkflowEvents/05_WorkflowEvents.csproj" />
     <Project Path="samples/Durable/Workflow/ConsoleApps/06_WorkflowSharedState/06_WorkflowSharedState.csproj" />
     <Project Path="samples/Durable/Workflow/ConsoleApps/07_SubWorkflows/07_SubWorkflows.csproj" />
+    <Project Path="samples/Durable/Workflow/ConsoleApps/08_WorkflowHITL/08_WorkflowHITL.csproj" />
   </Folder>
   <Folder Name="/Samples/Durable/Workflows/AzureFunctions/">
     <Project Path="samples/Durable/Workflow/AzureFunctions/01_SequentialWorkflow/01_SequentialWorkflow.csproj" />
     <Project Path="samples/Durable/Workflow/AzureFunctions/02_ConcurrentWorkflow/02_ConcurrentWorkflow.csproj" />
+    <Project Path="samples/Durable/Workflow/AzureFunctions/03_WorkflowHITL/03_WorkflowHITL.csproj" />
   </Folder>
   <Folder Name="/Samples/GettingStarted/">
     <File Path="samples/GettingStarted/README.md" />
@@ -475,4 +477,4 @@
     <Project Path="tests/Microsoft.Agents.AI.Workflows.Generators.UnitTests/Microsoft.Agents.AI.Workflows.Generators.UnitTests.csproj" />
     <Project Path="tests/Microsoft.Agents.AI.Workflows.UnitTests/Microsoft.Agents.AI.Workflows.UnitTests.csproj" />
   </Folder>
-</Solution>
+</Solution>

dotnet/samples/Durable/Workflow/AzureFunctions/03_WorkflowHITL/03_WorkflowHITL.csproj

@@ -0,0 +1,43 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net10.0</TargetFrameworks>
+    <AzureFunctionsVersion>v4</AzureFunctionsVersion>
+    <OutputType>Exe</OutputType>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+    <!-- The Functions build tools don't like namespaces that start with a number -->
+    <AssemblyName>WorkflowHITLFunctions</AssemblyName>
+    <RootNamespace>WorkflowHITLFunctions</RootNamespace>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <FrameworkReference Include="Microsoft.AspNetCore.App" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <None Include="local.settings.json" />
+  </ItemGroup>
+
+  <!-- Azure Functions packages -->
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Azure.Functions.Worker" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.DurableTask" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.DurableTask.AzureManaged" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Extensions.Http.AspNetCore" />
+    <PackageReference Include="Microsoft.Azure.Functions.Worker.Sdk" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Azure.Identity" />
+  </ItemGroup>
+
+  <!-- Local projects that should be switched to package references when using the sample outside of this MAF repo -->
+  <!--
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Agents.AI.Hosting.AzureFunctions" />
+  </ItemGroup>
+  -->
+  <ItemGroup>
+    <ProjectReference Include="..\..\..\..\..\src\Microsoft.Agents.AI.Hosting.AzureFunctions\Microsoft.Agents.AI.Hosting.AzureFunctions.csproj" />
+  </ItemGroup>
+</Project>

dotnet/samples/Durable/Workflow/AzureFunctions/03_WorkflowHITL/Executors.cs

@@ -0,0 +1,63 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+using Microsoft.Agents.AI.Workflows;
+
+namespace WorkflowHITLFunctions;
+
+/// <summary>Expense approval request passed to the RequestPort.</summary>
+public record ApprovalRequest(string ExpenseId, decimal Amount, string EmployeeName);
+
+/// <summary>Approval response received from the RequestPort.</summary>
+public record ApprovalResponse(bool Approved, string? Comments);
+
+/// <summary>Looks up expense details and creates an approval request.</summary>
+internal sealed class CreateApprovalRequest() : Executor<string, ApprovalRequest>("RetrieveRequest")
+{
+    public override ValueTask<ApprovalRequest> HandleAsync(
+        string message,
+        IWorkflowContext context,
+        CancellationToken cancellationToken = default)
+    {
+        // In a real scenario, this would look up expense details from a database
+        return new ValueTask<ApprovalRequest>(new ApprovalRequest(message, 1500.00m, "Jerry"));
+    }
+}
+
+/// <summary>Prepares the approval request for finance review after manager approval.</summary>
+internal sealed class PrepareFinanceReview() : Executor<ApprovalResponse, ApprovalRequest>("PrepareFinanceReview")
+{
+    public override ValueTask<ApprovalRequest> HandleAsync(
+        ApprovalResponse message,
+        IWorkflowContext context,
+        CancellationToken cancellationToken = default)
+    {
+        if (!message.Approved)
+        {
+            throw new InvalidOperationException("Cannot proceed to finance review — manager denied the expense.");
+        }
+
+        // In a real scenario, this would retrieve the original expense details
+        return new ValueTask<ApprovalRequest>(new ApprovalRequest("EXP-2025-001", 1500.00m, "Jerry"));
+    }
+}
+
+/// <summary>Processes the expense reimbursement based on the parallel approval responses.</summary>
+internal sealed class ExpenseReimburse() : Executor<ApprovalResponse[], string>("Reimburse")
+{
+    public override async ValueTask<string> HandleAsync(
+        ApprovalResponse[] message,
+        IWorkflowContext context,
+        CancellationToken cancellationToken = default)
+    {
+        // Check that all parallel approvals passed
+        ApprovalResponse? denied = Array.Find(message, r => !r.Approved);
+        if (denied is not null)
+        {
+            return $"Expense reimbursement denied. Comments: {denied.Comments}";
+        }
+
+        // Simulate payment processing
+        await Task.Delay(1000, cancellationToken);
+        return $"Expense reimbursed at {DateTime.UtcNow:O}";
+    }
+}

dotnet/samples/Durable/Workflow/AzureFunctions/03_WorkflowHITL/Program.cs

@@ -0,0 +1,51 @@
+// Copyright (c) Microsoft. All rights reserved.
+
+// This sample demonstrates a Human-in-the-Loop (HITL) workflow hosted in Azure Functions.
+//
+// ┌──────────────────────┐   ┌────────────────┐   ┌─────────────────────┐    ┌────────────────────┐
+// │ CreateApprovalRequest│──►│ManagerApproval │──►│PrepareFinanceReview │──┬►│  BudgetApproval    │──┐
+// └──────────────────────┘   │ (RequestPort)  │   └─────────────────────┘  │ │  (RequestPort)     │  │
+//                            └────────────────┘                            │ └────────────────────┘  │  ┌─────────────────┐
+//                                                                          │                         ├─►│ExpenseReimburse │
+//                                                                          │ ┌────────────────────┐  │  └─────────────────┘
+//                                                                          └►│ComplianceApproval  │──┘
+//                                                                            │  (RequestPort)     │
+//                                                                            └────────────────────┘
+//
+// The workflow pauses at three RequestPorts — one for the manager, then two in parallel for finance.
+// After manager approval, BudgetApproval and ComplianceApproval run concurrently via fan-out/fan-in.
+// The framework auto-generates three HTTP endpoints for each workflow:
+//   POST /api/workflows/{name}/run          - Start the workflow
+//   GET  /api/workflows/{name}/status/{id}  - Check status and pending approvals
+//   POST /api/workflows/{name}/respond/{id} - Send approval response to resume
+
+using Microsoft.Agents.AI.Hosting.AzureFunctions;
+using Microsoft.Agents.AI.Workflows;
+using Microsoft.Azure.Functions.Worker.Builder;
+using Microsoft.Extensions.Hosting;
+using WorkflowHITLFunctions;
+
+// Define executors and RequestPorts for the three HITL pause points
+CreateApprovalRequest createRequest = new();
+RequestPort<ApprovalRequest, ApprovalResponse> managerApproval = RequestPort.Create<ApprovalRequest, ApprovalResponse>("ManagerApproval");
+PrepareFinanceReview prepareFinanceReview = new();
+RequestPort<ApprovalRequest, ApprovalResponse> budgetApproval = RequestPort.Create<ApprovalRequest, ApprovalResponse>("BudgetApproval");
+RequestPort<ApprovalRequest, ApprovalResponse> complianceApproval = RequestPort.Create<ApprovalRequest, ApprovalResponse>("ComplianceApproval");
+ExpenseReimburse reimburse = new();
+
+// Build the workflow: CreateApprovalRequest -> ManagerApproval -> PrepareFinanceReview -> [BudgetApproval AND ComplianceApproval] -> ExpenseReimburse
+Workflow expenseApproval = new WorkflowBuilder(createRequest)
+    .WithName("ExpenseReimbursement")
+    .WithDescription("Expense reimbursement with manager and parallel finance approvals")
+    .AddEdge(createRequest, managerApproval)
+    .AddEdge(managerApproval, prepareFinanceReview)
+    .AddFanOutEdge(prepareFinanceReview, [budgetApproval, complianceApproval])
+    .AddFanInEdge([budgetApproval, complianceApproval], reimburse)
+    .Build();
+
+using IHost app = FunctionsApplication
+    .CreateBuilder(args)
+    .ConfigureFunctionsWebApplication()
+    .ConfigureDurableWorkflows(workflows => workflows.AddWorkflow(expenseApproval, exposeStatusEndpoint: true))
+    .Build();
+app.Run();

dotnet/samples/Durable/Workflow/AzureFunctions/03_WorkflowHITL/README.md

@@ -0,0 +1,196 @@
+# Human-in-the-Loop (HITL) Workflow — Azure Functions
+
+This sample demonstrates a durable workflow with Human-in-the-Loop support hosted in Azure Functions. The workflow pauses at three `RequestPort` nodes — one sequential manager approval, then two parallel finance approvals (budget and compliance) via fan-out/fan-in. Approval responses are sent via HTTP endpoints.
+
+## Key Concepts Demonstrated
+
+- Using multiple `RequestPort` nodes for sequential and parallel human-in-the-loop interactions in a durable workflow
+- Fan-out/fan-in pattern for parallel approval steps
+- Auto-generated HTTP endpoints for running workflows, checking status, and sending HITL responses
+- Pausing orchestrations via `WaitForExternalEvent` and resuming via `RaiseEventAsync`
+- Viewing inputs the workflow is waiting for via the status endpoint
+
+## Workflow
+
+This sample implements the following workflow:
+
+```
+┌──────────────────────┐   ┌────────────────┐   ┌─────────────────────┐    ┌────────────────────┐
+│ CreateApprovalRequest│──►│ManagerApproval │──►│PrepareFinanceReview │──┬►│  BudgetApproval    │──┐
+└──────────────────────┘   │ (RequestPort)  │   └─────────────────────┘  │ │  (RequestPort)     │  │
+                           └────────────────┘                            │ └────────────────────┘  │  ┌─────────────────┐
+                                                                         │                         ├─►│ExpenseReimburse │
+                                                                         │ ┌────────────────────┐  │  └─────────────────┘
+                                                                         └►│ComplianceApproval  │──┘
+                                                                           │  (RequestPort)     │
+                                                                           └────────────────────┘
+```
+
+## HTTP Endpoints
+
+The framework auto-generates these endpoints for workflows with `RequestPort` nodes:
+
+| Method | Endpoint | Description |
+|--------|----------|-------------|
+| POST | `/api/workflows/ExpenseReimbursement/run` | Start the workflow |
+| GET | `/api/workflows/ExpenseReimbursement/status/{runId}` | Check status and inputs the workflow is waiting for |
+| POST | `/api/workflows/ExpenseReimbursement/respond/{runId}` | Send approval response to resume |
+
+## Environment Setup
+
+See the [README.md](../../README.md) file in the parent directory for information on how to configure the environment, including how to install and run the Durable Task Scheduler.
+
+## Running the Sample
+
+With the environment setup and function app running, you can test the sample by sending HTTP requests to the workflow endpoints.
+
+You can use the `demo.http` file to trigger the workflow, or a command line tool like `curl` as shown below:
+
+### Step 1: Start the Workflow
+
+Bash (Linux/macOS/WSL):
+
+```bash
+curl -X POST http://localhost:7071/api/workflows/ExpenseReimbursement/run \
+    -H "Content-Type: text/plain" -d "EXP-2025-001"
+```
+
+PowerShell:
+
+```powershell
+Invoke-RestMethod -Method Post `
+    -Uri http://localhost:7071/api/workflows/ExpenseReimbursement/run `
+    -ContentType text/plain `
+    -Body "EXP-2025-001"
+```
+
+The response will confirm the workflow orchestration has started:
+
+```text
+Workflow orchestration started for ExpenseReimbursement. Orchestration runId: abc123def456
+```
+
+> **Tip:** You can provide a custom run ID by appending a `runId` query parameter:
+>
+> ```bash
+> curl -X POST "http://localhost:7071/api/workflows/ExpenseReimbursement/run?runId=expense-001" \
+>     -H "Content-Type: text/plain" -d "EXP-2025-001"
+> ```
+>
+> If not provided, a unique run ID is auto-generated.
+
+### Step 2: Check Workflow Status
+
+The workflow pauses at the `ManagerApproval` RequestPort. Query the status endpoint to see what input it is waiting for:
+
+```bash
+curl http://localhost:7071/api/workflows/ExpenseReimbursement/status/{runId}
+```
+
+```json
+{
+  "runId": "{runId}",
+  "status": "Running",
+  "waitingForInput": [
+    { "eventName": "ManagerApproval", "input": { "ExpenseId": "EXP-2025-001", "Amount": 1500.00, "EmployeeName": "Jerry" } }
+  ]
+}
+```
+
+> **Tip:** You can also verify this in the DTS dashboard at `http://localhost:8082`. Find the orchestration by its `runId` and you will see it is in a "Running" state, paused at a `WaitForExternalEvent` call for the `ManagerApproval` event.
+
+### Step 3: Send Manager Approval Response
+
+```bash
+curl -X POST http://localhost:7071/api/workflows/ExpenseReimbursement/respond/{runId} \
+    -H "Content-Type: application/json" \
+    -d '{"eventName": "ManagerApproval", "response": {"Approved": true, "Comments": "Approved by manager."}}'
+```
+
+```json
+{
+  "message": "Response sent to workflow.",
+  "runId": "{runId}",
+  "eventName": "ManagerApproval",
+  "validated": true
+}
+```
+
+### Step 4: Check Workflow Status Again
+
+The workflow now pauses at both the `BudgetApproval` and `ComplianceApproval` RequestPorts in parallel:
+
+```bash
+curl http://localhost:7071/api/workflows/ExpenseReimbursement/status/{runId}
+```
+
+```json
+{
+  "runId": "{runId}",
+  "status": "Running",
+  "waitingForInput": [
+    { "eventName": "BudgetApproval", "input": { "ExpenseId": "EXP-2025-001", "Amount": 1500.00, "EmployeeName": "Jerry" } },
+    { "eventName": "ComplianceApproval", "input": { "ExpenseId": "EXP-2025-001", "Amount": 1500.00, "EmployeeName": "Jerry" } }
+  ]
+}
+```
+
+### Step 5a: Send Budget Approval Response
+
+```bash
+curl -X POST http://localhost:7071/api/workflows/ExpenseReimbursement/respond/{runId} \
+    -H "Content-Type: application/json" \
+    -d '{"eventName": "BudgetApproval", "response": {"Approved": true, "Comments": "Budget approved."}}'
+```
+
+```json
+{
+  "message": "Response sent to workflow.",
+  "runId": "{runId}",
+  "eventName": "BudgetApproval",
+  "validated": true
+}
+```
+
+### Step 5b: Send Compliance Approval Response
+
+```bash
+curl -X POST http://localhost:7071/api/workflows/ExpenseReimbursement/respond/{runId} \
+    -H "Content-Type: application/json" \
+    -d '{"eventName": "ComplianceApproval", "response": {"Approved": true, "Comments": "Compliance approved."}}'
+```
+
+```json
+{
+  "message": "Response sent to workflow.",
+  "runId": "{runId}",
+  "eventName": "ComplianceApproval",
+  "validated": true
+}
+```
+
+### Step 6: Check Final Status
+
+After all approvals, the workflow completes and the expense is reimbursed:
+
+```bash
+curl http://localhost:7071/api/workflows/ExpenseReimbursement/status/{runId}
+```
+
+```json
+{
+  "runId": "{runId}",
+  "status": "Completed",
+  "waitingForInput": null
+}
+```
+
+### Viewing Workflows in the DTS Dashboard
+
+After running a workflow, you can navigate to the Durable Task Scheduler (DTS) dashboard to visualize the orchestration and inspect its execution history.
+
+If you are using the DTS emulator, the dashboard is available at `http://localhost:8082`.
+
+1. Open the dashboard and look for the orchestration instance matching the `runId` returned in Step 1 (e.g., `abc123def456` or your custom ID like `expense-001`).
+2. Click into the instance to see the execution timeline, which shows each executor activity and the `WaitForExternalEvent` pauses where the workflow waited for human input — including the two parallel finance approvals.
+3. Expand individual activity steps to inspect inputs and outputs — for example, the `ManagerApproval`, `BudgetApproval`, and `ComplianceApproval` external events will show the approval request sent and the response received.