Changed attempts to be in UI and now adding invalid to flight booking…

… in UI causing rollback/compensation

Signed-off-by: ktenzer <keith.tenzer@gmail.com>

README.md

@@ -47,7 +47,7 @@ Notice each is executed via an activity.
 
 ### Demo: Recover Forward (retries)
 
-In the `run_workflow.py` modify the global variable `ATTEMPTS = 1` to `ATTEMPTS = 3`, so that the `book_flight` Activity attempts a retry 3 times.
+Modify `Attempts = 1` to `Attempts = 3` in UI, so that the booking activities attempt a retry 3 times.
 Render your booking information in the Flask app <http://127.0.0.1:5000>, then see the tasks in the Web UI at <http://localhost:8233/>.
 
 Select your running or completed Workflow ID.
@@ -60,7 +60,7 @@ Then notice how the Workflow executes the compensations.
 
 ### Demo: Recover Backward (rollback)
 
-In the `run_workflow.py` modify the global variable `ATTEMPTS = 3` to `ATTEMPTS = 5`, so that the `book_flight` Activity attempts a retry 5 times.
+Modify `Flight = Alaska Airlines 123` to `Flight = invalid` in the UI, so that the `book_flight` Activity fails and a rollback occurs. 
 Render your booking information in the Flask app <http://127.0.0.1:5000>, then see the tasks in the Web UI at <http://localhost:8233/>.
 
 Select your running or completed Workflow ID.
@@ -69,7 +69,7 @@ Under **Recent** events, select the failed Activity, `book_flight` (in compact v
 
 Under **ActivityTaskStarted** you'll see the Attempts (5), and the stack trace message letting you know the last failed attempt.
 
-Under **ActivityTaskFailed** you'll see error `Too many retries, flight booking not possible at this time!`. You will also see that since the booking cannot be completed, rollback (undo) is performed using compensation.
+Under **ActivityTaskFailed** you'll see error `Invalid flight booking, rolling back!`. You will also see that since the booking cannot be completed, rollback (undo) is performed using compensation.
 
 ## Design
 

activities.py

@@ -15,28 +15,50 @@ class BookVacationInput:
 
 @activity.defn
 async def book_car(input: BookVacationInput) -> str:
+    await asyncio.sleep(3)
+    if activity.info().attempt < input.attempts:
+        activity.heartbeat(
+            f"Invoking activity, attempt number {activity.info().attempt}"
+        )
+        await asyncio.sleep(3)
+        raise RuntimeError("Car service is down")
+
+    if "invalid" in input.book_car_id:
+        raise Exception("Invalid car booking, rolling back!")
+
     print(f"Booking car: {input.book_car_id}")
     return f"Booked car: {input.book_car_id}"
 
 
 @activity.defn
 async def book_hotel(input: BookVacationInput) -> str:
+    await asyncio.sleep(3)
+    if activity.info().attempt < input.attempts:
+        activity.heartbeat(
+            f"Invoking activity, attempt number {activity.info().attempt}"
+        )
+        await asyncio.sleep(3)
+        raise RuntimeError("Hotel service is down")
+
+    if "invalid" in input.book_hotel_id:
+        raise Exception("Invalid hotel booking, rolling back!")
+
     print(f"Booking hotel: {input.book_hotel_id}")
     return f"Booked hotel: {input.book_hotel_id}"
 
 
 @activity.defn
 async def book_flight(input: BookVacationInput) -> str:
+    await asyncio.sleep(3)
     if activity.info().attempt < input.attempts:
         activity.heartbeat(
             f"Invoking activity, attempt number {activity.info().attempt}"
         )
-        await asyncio.sleep(1)
-        raise RuntimeError("Service is down")
-    elif activity.info().attempt > 3:
-        raise RuntimeError(
-            "Too many retries, flight booking not possible at this time!"
-        )
+        await asyncio.sleep(3)
+        raise RuntimeError("Flight service is down")
+
+    if "invalid" in input.book_flight_id:
+        raise Exception("Invalid flight booking, rolling back!")
 
     print(f"Booking flight: {input.book_flight_id}")
     return f"Booking flight: {input.book_flight_id}"

book_workflow.py

@@ -20,17 +20,20 @@ async def run(self, input: BookVacationInput):
                 book_car,
                 input,
                 start_to_close_timeout=timedelta(seconds=10),
+                retry_policy=RetryPolicy(
+                    non_retryable_error_types=["Exception"],
+                ),                  
             )
             compensations.append("undo_book_hotel")
             output += " " + await workflow.execute_activity(
                 book_hotel,
                 input,
                 start_to_close_timeout=timedelta(seconds=10),
+                retry_policy=RetryPolicy(
+                    non_retryable_error_types=["Exception"],
+                ),                
             )
 
-            # Sleep to simulate flight booking taking longer, allowing for worker restart while workflow running
-            await asyncio.sleep(15)
-
             compensations.append("undo_book_flight")
             output += " " + await workflow.execute_activity(
                 book_flight,

run_workflow.py

@@ -24,16 +24,17 @@ async def display_form():
 @app.route("/book", methods=["POST"])
 async def book_vacation():
     user_id = f'{request.form.get("name").replace(" ", "-").lower()}-{str(uuid.uuid4().int)[:6]}'
+    attempts = request.form.get("attempts")
     car = request.form.get("car")
     hotel = request.form.get("hotel")
     flight = request.form.get("flight")
 
     input = BookVacationInput(
+        attempts=int(attempts),
         book_user_id=user_id,
         book_car_id=car,
         book_hotel_id=hotel,
         book_flight_id=flight,
-        attempts=ATTEMPTS,
     )
 
     if (

templates/book_vacation.html

@@ -105,6 +105,15 @@ <h2>GitHub: <a href="https://github.com/temporalio">github.com/temporalio</a></h
     <h2>Docs: <a href="https://docs.temporal.io">docs.temporal.io</a></h2>
     <p>Eliminate complex error or retry logic, avoid callbacks, and ensure that every workflow you start, completes. Temporal delivers durable execution for your services and applications.</p>
     <form method="post" action="/book">
+      <label for="name">Attempts:</label>
+      <input
+        type="text"
+        name="attempts"
+        id="attempts"
+        value="1"
+        required
+        placeholder="Your Temporal User"
+      /><br />      
       <label for="name">Name:</label>
       <input
         type="text"