Add a Job manager #706

dotMorten · 2025-12-15T22:14:14Z

A port of the Swift toolkit JobManager. See: https://github.com/Esri/arcgis-maps-sdk-swift-toolkit/blob/117a0a35662f7a2403b22d7048e4f0c53a97c07c/Sources/ArcGISToolkit/Components/JobManager/JobManager.swift

prathameshnarkhede · 2025-12-19T19:18:59Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+        /// <summary>
+        /// Gets the shared job manager.
+        /// </summary>
+        public static JobManager Shared { get; } = new JobManager(null);


Could this lead to a thread-safety issue? It might be a good idea to use Lazy loading for initialization to ensure safe and efficient singleton creation.

prathameshnarkhede · 2025-12-19T19:30:40Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+            var array = Jobs.Select(j => j.ToJson()).ToArray();
+            lock (StateLock)
+            {
+                SaveState(string.Join("\n", array));


It looks like this implementation assumes there won't be any newline characters in actual SaveState data. If any serialized job contains a newline in a field like an error message or log. Splitting on \n character could break the deserialization.

+1 on this. Newline-delimited JSON seems really fragile.

prathameshnarkhede · 2025-12-19T19:44:42Z

src/Toolkit/Toolkit/JobManager/JobManager.Windows.cs

+            }
+            try
+            {
+                // TODO: Check app manifest for background task declaration and provide better instructions how to register the background task


Should this requirement be documented in the Readme about silent failures if not configured correctly?

Also, I was curious if the success and failure behavior are consistent across the platforms?

prathameshnarkhede · 2025-12-19T20:10:45Z

src/Samples/Toolkit.SampleApp.Maui/Toolkit.SampleApp.Maui.csproj

    <PackageReference Include="Microsoft.Maui.Controls" Version="$(MauiVersion)" />
    <PackageReference Include="Microsoft.Maui.Controls.Compatibility" Version="$(MauiVersion)" />
+    <PackageReference Include="Esri.Calcite.Maui" Version="1.0.0-rc.1" />
+  </ItemGroup>


This closing tag seems duplicated.

prathameshnarkhede · 2025-12-19T20:30:11Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+        /// <summary>
+        /// The jobs being managed by the job manager.
+        /// </summary>
+        public IList<IJob> Jobs { get; } = new System.Collections.ObjectModel.ObservableCollection<IJob>();


This will reinitialize the Jobs collection every time we call get on Jobs and seems like a bug. We can make use of private backing field which stays for the lifetime of the JobManager.

prathameshnarkhede · 2025-12-19T21:01:31Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+        public async Task PerformStatusChecks()
+        {
+            var tasks = Jobs.Select(async job =>
+            {
+                try { await job.CheckStatusAsync(); } catch { }
+            });
+            await Task.WhenAll(tasks);
+        }


This process could be made faster using SimaphoreSlim or Parallel.ForEachAsync which supports concurrency.

Probably not -- CheckStatusAsync yields almost immediately, after signaling a background thread in core. So we queue up all the checks and await them in parallel using Task.WhenAll. This is about as efficient as it can get.

mstefarov · 2025-12-19T21:11:10Z

src/Samples/Toolkit.SampleApp.Maui/Samples/JobManagerSample.xaml.cs

+                }
+            }
+
+            var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), new Guid().ToString() + ".geodatabase");


new Guid() is the default constructor -- it's always going to be 00000000-0000-0000-0000-000000000000. Did you mean to do Guid.NewGuid()?

Suggested change

var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), new Guid().ToString() + ".geodatabase");

var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), Guid.NewGuid().ToString() + ".geodatabase");

mstefarov · 2025-12-19T21:13:21Z

src/Samples/Toolkit.SampleApp.Maui/Samples/JobView.xaml.cs

+    private void OnJobPropertyChanged(IJob? oldJob, IJob? newJob)
+    {
+        if (oldJob is not null)
+            oldJob.ProgressChanged -= Job_ProgressChanged;


Should this unsubscribe from oldJob.StatusChanged too -- like we do for ProgressChanged?

mstefarov · 2025-12-19T21:26:45Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+        /// </summary>
+        public void SaveState()
+        {
+            var array = Jobs.Select(j => j.ToJson()).ToArray();


Events like ProgressChanged/StatusChanged will be coming from background threads and calling SaveState. Do we need some locks around this to avoid overlapping saves? Or e.g. what if user adds a Job (modifying Jobs collection) on the UI thread while SaveState is enumerating in the background? That's a recipe for "collection was modified" exceptions.

mstefarov · 2025-12-19T21:30:54Z

src/Toolkit/Toolkit/JobManager/JobManager.iOS.cs

+                if (value != BackgroundStatusCheckSchedule.Disabled && ValidateInfoPlist())
+                    _preferredBackgroundStatusCheckSchedule = value;


If you ever enable this property, it would be impossible to disable due to this if check. Is that intentional?

mstefarov · 2025-12-19T21:33:10Z

src/Toolkit/Toolkit/JobManager/JobManager.iOS.cs

+            return false;
+            throw new InvalidOperationException($"'BGTaskSchedulerPermittedIdentifiers' must contain '{DefaultsKey}'.");


Were you undecided about returning or throwing? The xmldoc on PreferredBackgroundStatusCheckSchedule says that we throw, but the setter actually just fails. The throw is unreachable.

mstefarov · 2025-12-19T21:34:03Z

src/Toolkit/Toolkit/JobManager/JobManager.iOS.cs

+            _isBackgroundStatusChecksScheduled = true;
+            var request = new BGAppRefreshTaskRequest(StatusChecksTaskIdentifier)
+            {
+                EarliestBeginDate = NSDate.Now.AddSeconds(PreferredBackgroundStatusCheckSchedule.Interval)
+            };
+            NSError error;
+            BGTaskScheduler.Shared.Submit(request, out error);


Should we perhaps check the error before setting _isBackgroundStatusChecksScheduled to true? It might have failed, e.g.

There can be a total of 1 refresh task and 10 processing tasks scheduled at any time. Trying to schedule more tasks returns BGTaskScheduler.Error.Code.tooManyPendingTaskRequests.

mstefarov · 2025-12-19T21:39:10Z

src/Toolkit/Toolkit/JobManager/JobManager.iOS.cs

+    public class BackgroundStatusCheckSchedule
+    {
+        public static readonly BackgroundStatusCheckSchedule Disabled = new BackgroundStatusCheckSchedule();
+        public static BackgroundStatusCheckSchedule RegularInterval(double interval) => new BackgroundStatusCheckSchedule { Interval = interval };
+        public double Interval { get; private set; }
+    }


This class could use a bit of doc. Also, it seems that you meant to make this factory-constructible -- should we make the default constructor private?

And while you're at it, the units of interval are not self-explanatory. How about using TimeSpan instead?

mstefarov · 2025-12-19T22:06:14Z

src/Toolkit/Toolkit/JobManager/JobManager.Windows.cs

+            private IBackgroundTaskInstance? _taskInstance;
+
+            [MTAThread]
+            public void Run(IBackgroundTaskInstance taskInstance)


Is the _taskInstance field meant to be initialized here? Nothing assigns to that field right now.

mstefarov · 2025-12-19T22:16:49Z

src/Toolkit/Toolkit/JobManager/JobManager.Windows.cs

+            {
+
+                var taskId = taskInstance.Task.Name;
+                manager = JobManager.Create(taskId);


How does the BackgroundTask's JobManager communicate with the original JobManager that started it? Are they meant to pass state around via the shared state file? That seems pretty fragile -- both managers will be trying to read/write that file with no coordination.

As far as I can tell we never name our BackgroundTaskBuilder, so wouldn't taskId always be empty here?

mstefarov · 2025-12-19T22:17:25Z

src/Toolkit/Toolkit/JobManager/JobManager.cs

+            var array = Jobs.Select(j => j.ToJson()).ToArray();
+            lock (StateLock)
+            {
+                SaveState(string.Join("\n", array));


+1 on this. Newline-delimited JSON seems really fragile.

Morten Nielsen and others added 7 commits December 10, 2025 17:30

Adds a job manager for managing and resuming jobs

15f51e8

Improved job manager support

28f6088

Add jobmanager sample to WPF

6ae2659

WPF Sample Improvements

801425c

Add Maui JobManager sample

0dc6606

Clean up UI

bdae5e7

Clean-up

7105b7c

dotMorten requested review from mstefarov and prathameshnarkhede December 15, 2025 22:14

dotMorten self-assigned this Dec 15, 2025

prathameshnarkhede reviewed Dec 19, 2025

View reviewed changes

mstefarov requested changes Dec 19, 2025

View reviewed changes

	var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), new Guid().ToString() + ".geodatabase");
	var path = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), Guid.NewGuid().ToString() + ".geodatabase");

		if (value != BackgroundStatusCheckSchedule.Disabled && ValidateInfoPlist())
		_preferredBackgroundStatusCheckSchedule = value;

		return false;
		throw new InvalidOperationException($"'BGTaskSchedulerPermittedIdentifiers' must contain '{DefaultsKey}'.");

Add a Job manager #706

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