From eb623e34608766bd95949583db9e848585a60a6a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Loren=20=F0=9F=A4=93?= <lorensr@gmail.com>
Date: Thu, 28 Mar 2024 19:16:14 -0400
Subject: [PATCH] handle cancellation

---
 README.md                          |  2 +-
 src/Timer/README.md                |  2 +-
 src/Timer/Subscription.workflow.cs | 22 ++++++++++++++++------
 3 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index 059e499..2949982 100644
--- a/README.md
+++ b/README.md
@@ -23,7 +23,7 @@ Prerequisites:
 * [Polling](src/Polling) - Recommended implementation of an activity that needs to periodically poll an external resource waiting its successful completion.
 * [Saga](src/Saga) - Demonstrates how to implement a saga pattern.
 * [Schedules](src/Schedules) - How to schedule workflows to be run at specific times in the future.
-* [Timer](src/Timer) - Use a timer to implement a monthly subscription.
+* [Timer](src/Timer) - Use a timer to implement a monthly subscription; handle workflow cancellation.
 * [WorkerSpecificTaskQueues](src/WorkerSpecificTaskQueues) - Use a unique task queue per Worker to have certain Activities only run on that specific Worker.
 * [WorkerVersioning](src/WorkerVersioning) - How to use the Worker Versioning feature to more easily deploy changes to Workflow & other code.
 * [WorkflowUpdate](src/WorkflowUpdate) - How to use the Workflow Update feature while blocking in update method for concurrent updates.
diff --git a/src/Timer/README.md b/src/Timer/README.md
index afd51a8..d2cb03f 100644
--- a/src/Timer/README.md
+++ b/src/Timer/README.md
@@ -1,6 +1,6 @@
 # Timer
 
-Use a timer (`Workflow.DelayAsync`) to implement a monthly subscription.
+Use a timer (`Workflow.DelayAsync`) to implement a monthly subscription. Also, handle workflow cancellation.
 
 To run, first see [README.md](../../README.md) for prerequisites. Then, run the following from this directory
 in a separate terminal to start the worker:
diff --git a/src/Timer/Subscription.workflow.cs b/src/Timer/Subscription.workflow.cs
index 2f621ba..9d6bf24 100644
--- a/src/Timer/Subscription.workflow.cs
+++ b/src/Timer/Subscription.workflow.cs
@@ -9,14 +9,24 @@ public class Subscription
     [WorkflowRun]
     public async Task RunAsync(string userId)
     {
-        while (true)
+        try
         {
-            await Workflow.DelayAsync(TimeSpan.FromDays(30));
+            while (true)
+            {
+                await Workflow.DelayAsync(TimeSpan.FromDays(30));
 
-            var result = await Workflow.ExecuteActivityAsync(
-                () => MyActivities.Charge(userId),
-                new() { StartToCloseTimeout = TimeSpan.FromMinutes(5) });
-            Workflow.Logger.LogInformation("Activity result: {Result}", result);
+                var result = await Workflow.ExecuteActivityAsync(
+                    () => MyActivities.Charge(userId),
+                    new() { StartToCloseTimeout = TimeSpan.FromMinutes(5) });
+                Workflow.Logger.LogInformation("Activity result: {Result}", result);
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            Workflow.Logger.LogInformation("Workflow cancelled, cleaning up...");
+            // Handle any cleanup here
+            // Re-throw to close the workflow as Cancelled. Otherwise, it will be closed as Completed.
+            throw;
         }
     }
 }
\ No newline at end of file