feat: Allow forcing of event method for requeued resource (#245)

* Add ability to specify event type when requeueing
* Add setting to have requeue use the same callback as originally used

Author: erin-allison

src/KubeOps/Operator/Controller/ManagedResourceController{TEntity}.cs

@@ -33,7 +33,7 @@ internal class ManagedResourceController<TEntity> : IManagedResourceController
         private readonly OperatorSettings _settings;
         private readonly IFinalizerManager<TEntity> _finalizerManager;
 
-        private readonly Subject<(TEntity Resource, TimeSpan Delay)>
+        private readonly Subject<RequeuedEvent>
             _requeuedEvents = new();
 
         private readonly Subject<QueuedEvent>
@@ -85,9 +85,17 @@ public ManagedResourceController(
         private IObservable<Unit> RequeuedEvents => _requeuedEvents
             .Do(_ => _metrics.RequeuedEvents.Inc())
             .Select(
-                data => Observable.Return(data.Resource).Delay(data.Delay))
+                data => Observable.Return(data).Delay(data.Delay))
             .Switch()
-            .Select(data => Observable.FromAsync(() => UpdateResourceData(data)))
+            .Select(data =>
+                Observable.FromAsync(async () =>
+                {
+                    var queuedEvent = await UpdateResourceData(data.Resource);
+
+                    return data.ResourceEvent.HasValue && queuedEvent != null
+                        ? queuedEvent with { ResourceEvent = data.ResourceEvent.Value }
+                        : queuedEvent;
+                }))
             .Switch()
             .Where(data => data != null)
             .Do(
@@ -269,13 +277,32 @@ protected async Task HandleResourceEvent(QueuedEvent? data)
                         resource.Name());
                     return;
                 case RequeueEventResult requeue:
-                    _logger.LogInformation(
-                        @"Event type ""{eventType}"" on resource ""{kind}/{name}"" successfully reconciled. Requeue requested with delay ""{requeue}"".",
-                        @event,
-                        resource.Kind,
-                        resource.Name(),
-                        requeue.RequeueIn);
-                    _requeuedEvents.OnNext((resource, requeue.RequeueIn));
+                    if (_settings.DefaultRequeueAsSameType)
+                    {
+                        requeue = new RequeueEventResult(requeue.RequeueIn, @event);
+                    }
+
+                    if (requeue.EventType.HasValue)
+                    {
+                        _logger.LogInformation(
+                            @"Event type ""{eventType}"" on resource ""{kind}/{name}"" successfully reconciled. Requeue requested as type ""{requeueType}"" with delay ""{requeue}"".",
+                            @event,
+                            resource.Kind,
+                            resource.Name(),
+                            requeue.EventType,
+                            requeue.RequeueIn);
+                    }
+                    else
+                    {
+                        _logger.LogInformation(
+                            @"Event type ""{eventType}"" on resource ""{kind}/{name}"" successfully reconciled. Requeue requested with delay ""{requeue}"".",
+                            @event,
+                            resource.Kind,
+                            resource.Name(),
+                            requeue.RequeueIn);
+                    }
+
+                    _requeuedEvents.OnNext(new RequeuedEvent(requeue.EventType, resource, requeue.RequeueIn));
                     break;
             }
         }
@@ -417,5 +444,7 @@ private TimeSpan ExponentialBackoff(int retryCount) => TimeSpan
             .Add(TimeSpan.FromMilliseconds(_rnd.Next(0, 1000)));
 
         internal record QueuedEvent(ResourceEventType ResourceEvent, TEntity Resource, int RetryCount = 0);
+
+        private record RequeuedEvent(ResourceEventType? ResourceEvent, TEntity Resource, TimeSpan Delay);
     }
 }

src/KubeOps/Operator/Controller/Results/RequeueEventResult.cs

@@ -1,4 +1,5 @@
 using System;
+using KubeOps.Operator.Kubernetes;
 
 namespace KubeOps.Operator.Controller.Results
 {
@@ -8,5 +9,10 @@ public RequeueEventResult(TimeSpan requeueIn)
             : base(requeueIn)
         {
         }
+
+        public RequeueEventResult(TimeSpan requeueIn, ResourceEventType eventType)
+            : base(requeueIn, eventType)
+        {
+        }
     }
 }

src/KubeOps/Operator/Controller/Results/ResourceControllerResult.cs

@@ -1,4 +1,5 @@
 using System;
+using KubeOps.Operator.Events;
 using KubeOps.Operator.Kubernetes;
 
 namespace KubeOps.Operator.Controller.Results
@@ -10,13 +11,27 @@ namespace KubeOps.Operator.Controller.Results
     /// </summary>
     public abstract class ResourceControllerResult
     {
-        internal ResourceControllerResult(TimeSpan delay) => RequeueIn = delay;
+        internal ResourceControllerResult(TimeSpan delay)
+        {
+            RequeueIn = delay;
+        }
+
+        internal ResourceControllerResult(TimeSpan delay, ResourceEventType eventType)
+        {
+            RequeueIn = delay;
+            EventType = eventType;
+        }
 
         /// <summary>
         /// Time that should be waited for a requeue.
         /// </summary>
         public TimeSpan RequeueIn { get; }
 
+        /// <summary>
+        /// Type of the event to be queued.
+        /// </summary>
+        public ResourceEventType? EventType { get; }
+
         /// <summary>
         /// Create a <see cref="ResourceControllerResult"/> that requeues a resource
         /// with a given delay. When the event fires (after the delay) the resource
@@ -31,6 +46,21 @@ public abstract class ResourceControllerResult
         public static ResourceControllerResult RequeueEvent(TimeSpan delay)
             => new RequeueEventResult(delay);
 
-        // TODO: Requeue with forced event method
+        /// <summary>
+        /// Create a <see cref="ResourceControllerResult"/> that requeues a resource
+        /// with a given delay. When the event fires (after the delay) the resource
+        /// cache is ignored in favor the specified <see cref="ResourceEventType"/>.
+        /// Based on the specified type, the new event triggers the according function.
+        /// </summary>
+        /// <param name="delay">
+        /// The delay. Please note, that a delay of <see cref="TimeSpan.Zero"/>
+        /// will result in an immediate trigger of the function. This can lead to infinite circles.
+        /// </param>
+        /// <param name="eventType">
+        /// The event type to queue.
+        /// </param>
+        /// <returns>The <see cref="ResourceControllerResult"/> with the configured delay and event type.</returns>
+        public static ResourceControllerResult RequeueEvent(TimeSpan delay, ResourceEventType eventType)
+            => new RequeueEventResult(delay, eventType);
     }
 }

src/KubeOps/Operator/OperatorSettings.cs

@@ -78,5 +78,17 @@ public sealed class OperatorSettings
         /// <para>The search will be performed on each "Start" of the controller.</para>
         /// </summary>
         public bool PreloadCache { get; set; }
+
+        /// <summary>
+        /// <para>
+        /// If set to true, returning `ResourceControllerResult.RequeueEvent` will
+        /// automatically requeue the event as the same type.
+        /// </para>
+        /// <para>
+        /// For example, if done from a "Created" event, the event will be queued
+        /// again as "Created" instead of (for example) "NotModified".
+        /// </para>
+        /// </summary>
+        public bool DefaultRequeueAsSameType { get; set; } = false;
     }
 }