agent-framework/dotnet/samples/DurableAgents/ConsoleApps/10_Workflow_HITL

Workflow Human-in-the-Loop (HITL) Sample

This sample demonstrates a Human-in-the-Loop pattern in durable workflows using RequestPort. The workflow pauses execution to wait for external input (e.g., manager approval) and resumes when the response is provided.

Overview

The sample implements an expense approval workflow:

1. CreateApprovalRequest - Retrieves expense details and creates an approval request
2. ManagerApproval (RequestPort) - Pauses workflow to wait for manager approval
3. ExpenseReimburse - Processes the reimbursement based on approval response

Workflow Flow

User Input (Expense ID)
       |
       v
+---------------------+
| CreateApprovalRequest|  Creates ApprovalRequest with expense details
+---------------------+
       |
       v
+---------------------+
|  ManagerApproval    |  RequestPort - PAUSES here waiting for external input
|   (RequestPort)     |  Workflow is durable while waiting
+---------------------+
       |
       v  (ApprovalResponse)
+---------------------+
|  ExpenseReimburse   |  Processes reimbursement if approved
+---------------------+
       |
       v
    Result

Key Concepts

• RequestPort - A special executor that pauses the workflow and waits for external input
• DurableRequestInfoEvent - Event emitted when the workflow reaches a RequestPort
• SendResponseAsync - Method to provide the response and resume the workflow
• Durability - The workflow can survive process restarts while waiting for human input

Code Highlights

Defining the RequestPort

RequestPort<ApprovalRequest, ApprovalResponse> managerApproval = 
    RequestPort.Create<ApprovalRequest, ApprovalResponse>("ManagerApproval");

Handling the Request Event

await foreach (WorkflowEvent evt in run.WatchStreamAsync())
{
    switch (evt)
    {
        case DurableRequestInfoEvent requestEvent:
            // Workflow is waiting for input
            ApprovalResponse response = HandleApprovalRequest(requestEvent);
            await run.SendResponseAsync(requestEvent, response);
            break;
        // ... other events
    }
}

Environment Setup

See the README.md file in the parent directory for environment configuration.

Running the Sample

cd dotnet/samples/DurableAgents/ConsoleApps/10_Workflow_HITL
dotnet run --framework net10.0

Sample Output

Starting expense reimbursement workflow for expense: EXP-2025-001
Workflow started with instance ID: abc123...
Watching for workflow events...

Workflow is waiting for input at RequestPort: ManagerApproval
  Input data: {"ExpenseId":"EXP-2025-001","Amount":1500.00,"EmployeeName":"Jerry"}
  Expected response type: SingleAgent.ApprovalResponse
  Approval request for: Jerry, Amount: $1,500.00
  Response sent: Approved=True

Workflow completed with result: Expense reimbursed at 1/23/2025 5:30:00 PM