From 8f541f8ea1a3d3b8e57fb750e5cbc8ff5bea24af Mon Sep 17 00:00:00 2001
From: Tim Haasdyk <tim_haasdyk@sil.org>
Date: Fri, 17 Jan 2025 15:27:46 +0100
Subject: [PATCH] Catch and ignore expected exceptions (#1386)

---
 backend/FwLite/FwLiteShared/Auth/OAuthService.cs  | 15 +++++++++++----
 .../FwLiteShared/Sync/BackgroundSyncService.cs    | 15 +++++++++++----
 2 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/backend/FwLite/FwLiteShared/Auth/OAuthService.cs b/backend/FwLite/FwLiteShared/Auth/OAuthService.cs
index b67f77032..f018c7108 100644
--- a/backend/FwLite/FwLiteShared/Auth/OAuthService.cs
+++ b/backend/FwLite/FwLiteShared/Auth/OAuthService.cs
@@ -74,11 +74,18 @@ private readonly Channel<OAuthLoginRequest>
 
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
-        await foreach (var loginRequest in _requestChannel.Reader.ReadAllAsync(stoppingToken))
+        try
+        {
+            await foreach (var loginRequest in _requestChannel.Reader.ReadAllAsync(stoppingToken))
+            {
+                //don't await, otherwise we'll block the channel reader and only 1 login will be processed at a time
+                //cancel the login after 5 minutes, otherwise it'll probably hang forever and abandoned requests will never be cleaned up
+                _ = Task.Run(() => StartLogin(loginRequest, stoppingToken.Merge(new CancellationTokenSource(TimeSpan.FromMinutes(5)).Token)), stoppingToken);
+            }
+        }
+        catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
         {
-            //don't await, otherwise we'll block the channel reader and only 1 login will be processed at a time
-            //cancel the login after 5 minutes, otherwise it'll probably hang forever and abandoned requests will never be cleaned up
-            _ = Task.Run(() => StartLogin(loginRequest, stoppingToken.Merge(new CancellationTokenSource(TimeSpan.FromMinutes(5)).Token)), stoppingToken);
+            // Expected during shutdown
         }
     }
 
diff --git a/backend/FwLite/FwLiteShared/Sync/BackgroundSyncService.cs b/backend/FwLite/FwLiteShared/Sync/BackgroundSyncService.cs
index e12033f60..b92868099 100644
--- a/backend/FwLite/FwLiteShared/Sync/BackgroundSyncService.cs
+++ b/backend/FwLite/FwLiteShared/Sync/BackgroundSyncService.cs
@@ -74,11 +74,18 @@ protected override async Task ExecuteAsync(CancellationToken stoppingToken)
             await SyncProject(crdtProject, true, stoppingToken);
         }
 
-        await foreach (var project in _syncResultsChannel.Reader.ReadAllAsync(stoppingToken))
+        try
+        {
+            await foreach (var project in _syncResultsChannel.Reader.ReadAllAsync(stoppingToken))
+            {
+                //todo, this might not be required, but I can't remember why I added it
+                await Task.Delay(100, stoppingToken);
+                await SyncProject(project, false, stoppingToken);
+            }
+        }
+        catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
         {
-            //todo, this might not be required, but I can't remember why I added it
-            await Task.Delay(100, stoppingToken);
-            await SyncProject(project, false, stoppingToken);
+            // Expected during shutdown
         }
     }