# Single Workflow Console Sample

This sample demonstrates how to run a workflow as a durable orchestration from a console application using the Durable Task Framework. It showcases the **durability** aspect - if the process crashes mid-execution, the workflow can be resumed without re-executing completed activities.

## Overview

The sample implements an order cancellation workflow with three executors, each with artificial delays to simulate real-world operations:

1. **OrderLookup** (2 seconds) - Looks up an order by its ID
2. **OrderCancel** (5 seconds) - Marks the order as cancelled
3. **SendEmail** (1 second) - Sends a cancellation confirmation email

## Durability Demonstration

The key feature of Durable Task Framework is **durability**:


- **Activity results are persisted**: When an activity completes, its result is saved
- **Orchestrations are replayed**: On restart, the orchestration replays from the beginning
- **Completed activities are skipped**: The framework uses cached results for completed activities
- **Failed activities are retried**: If an activity was interrupted, it runs again
- **Automatic resume**: When the worker starts, it automatically picks up any pending work!

### Try It Yourself

1. Start the application and enter an order ID (e.g., `12345`)
2. Stop the app (Ctrl+C or stop debugging) during the `OrderCancel` activity (5 seconds)
3. Restart the application
4. **Watch for automatic resume!** The worker automatically picks up the interrupted workflow
5. Observe that `OrderLookup` is NOT re-executed (its result was cached)
6. `OrderCancel` restarts from the beginning (it didn't complete)
7. `SendEmail` runs after `OrderCancel` completes

The durability is completely automatic - no manual intervention needed!

## Workflow Flow

```
User Input (Order ID)
       ?
       ?
???????????????????
?  OrderLookup    ?  ? 2 second delay (database lookup)
?  (2 seconds)    ?
???????????????????
         ?
         ?
???????????????????
?  OrderCancel    ?  ? 5 second delay - TRY INTERRUPTING HERE!
?  (5 seconds)    ?
???????????????????
         ?
         ?
???????????????????
?   SendEmail     ?  ? 1 second delay (email sending)
?  (1 second)     ?
???????????????????
         ?
         ?
      Result
```

## Key Concepts Demonstrated

- **ConfigureDurableWorkflows** - Simplified API for registering workflows
- **DurableExecution.RunAsync** - Start a new workflow (similar to InProcessExecution)
- **DurableRun** - Handle to monitor and interact with a running workflow
- **Automatic Resume** - Interrupted workflows continue automatically on restart

## Environment Setup

See the [README.md](../README.md) file in the parent directory for more information on how to configure the environment, including how to install and run common sample dependencies.

## Running the Sample

With the environment setup, you can run the sample:

```bash
cd dotnet/samples/DurableAgents/ConsoleApps/08_SingleWorkflow
dotnet run --framework net10.0
```

### Sample Session

```text
??????????????????????????????????????????????????????????????????????
?           Durable Workflow Console Sample                          ?
??????????????????????????????????????????????????????????????????????
?  This sample demonstrates durability in workflows.                 ?
?  Workflow: OrderLookup (2s) -> OrderCancel (5s) -> SendEmail (1s)  ?
??????????????????????????????????????????????????????????????????????

?? TIP: Stop the app during OrderCancel (5 seconds) to test durability!
   Restart the app - it will automatically resume from where it left off.

? Checking for pending workflows...

Enter an order ID to start a new workflow (or 'exit' to quit):

Order ID: 12345

Starting workflow for order '12345'...
Instance ID: abc123-def456-...

???????????????????????????????????????????????????????????????????
? [Activity] OrderLookup: Starting lookup for order '12345'
? [Activity] OrderLookup: Found order '12345' for customer 'Jerry'
???????????????????????????????????????????????????????????????????

???????????????????????????????????????????????????????????????????
? [Activity] OrderCancel: Starting cancellation for order '12345'
? [Activity] OrderCancel: ??  This takes 5 seconds - try Ctrl+C!
? [Activity] OrderCancel: Processing... 1/5 seconds
? [Activity] OrderCancel: Processing... 2/5 seconds
^C   <-- User stops the app here

[After restart...]

? Checking for pending workflows...

???????????????????????????????????????????????????????????????????
? [Activity] OrderCancel: Starting cancellation for order '12345'  <-- Auto-resumed!
? [Activity] OrderCancel: ??  This takes 5 seconds - try Ctrl+C!
? [Activity] OrderCancel: Processing... 1/5 seconds
...
? [Activity] OrderCancel: ? Order '12345' has been cancelled
???????????????????????????????????????????????????????????????????

???????????????????????????????????????????????????????????????????
? [Activity] SendEmail: Sending email to 'jerry@example.com'...
? [Activity] SendEmail: ? Email sent successfully!
???????????????????????????????????????????????????????????????????

Enter an order ID to start a new workflow (or 'exit' to quit):

Order ID: _
```

Notice that when resumed:
- `OrderLookup` was **NOT re-executed** (result was cached by Durable Task)
- `OrderCancel` **restarted automatically** (it was interrupted before completing)
- `SendEmail` ran normally after `OrderCancel` completed

## Viewing Workflow State

You can view the state of the workflow in the Durable Task Scheduler dashboard:

1. Open your browser and navigate to `http://localhost:8082`
2. In the dashboard, you can view the state of the orchestration, including activity history and current state

## Related Samples

- [01_SingleAgent](../01_SingleAgent) - Single agent console sample
- [02_AgentOrchestration_Chaining](../02_AgentOrchestration_Chaining) - Agent chaining with durable orchestration
- [05_AgentOrchestration_HITL](../05_AgentOrchestration_HITL) - Human-in-the-loop orchestration
- [09_Workflow](../../AzureFunctions/09_Workflow) - Azure Functions version of workflow hosting