From 59c2db992c7c5373c5125ec52a2eb8418cc119bc Mon Sep 17 00:00:00 2001
From: Hidde Beydals <hiddeco@users.noreply.github.com>
Date: Wed, 27 Nov 2024 00:06:24 +0100
Subject: [PATCH] fix(controller): add `IgnoreDelete` predicate (#3003)

Signed-off-by: Hidde Beydals <hidde@hhh.computer>
---
 internal/controller/promotions/promotions.go  |  2 ++
 .../controller/stages/control_flow_stages.go  |  2 ++
 internal/controller/stages/regular_stages.go  |  2 ++
 internal/controller/warehouses/warehouses.go  | 11 ++--------
 internal/predicate/ignore_delete.go           | 20 +++++++++++++++++++
 5 files changed, 28 insertions(+), 9 deletions(-)
 create mode 100644 internal/predicate/ignore_delete.go

diff --git a/internal/controller/promotions/promotions.go b/internal/controller/promotions/promotions.go
index 4b89815c0..138cc5beb 100644
--- a/internal/controller/promotions/promotions.go
+++ b/internal/controller/promotions/promotions.go
@@ -31,6 +31,7 @@ import (
 	"github.com/akuity/kargo/internal/kubeclient"
 	libEvent "github.com/akuity/kargo/internal/kubernetes/event"
 	"github.com/akuity/kargo/internal/logging"
+	intpredicate "github.com/akuity/kargo/internal/predicate"
 )
 
 // ReconcilerConfig represents configuration for the promotion reconciler.
@@ -114,6 +115,7 @@ func SetupReconcilerWithManager(
 
 	c, err := ctrl.NewControllerManagedBy(kargoMgr).
 		For(&kargoapi.Promotion{}).
+		WithEventFilter(intpredicate.IgnoreDelete[client.Object]{}).
 		WithEventFilter(predicate.Or(
 			predicate.GenerationChangedPredicate{},
 			kargo.RefreshRequested{},
diff --git a/internal/controller/stages/control_flow_stages.go b/internal/controller/stages/control_flow_stages.go
index 2a6a11ecd..4445be621 100644
--- a/internal/controller/stages/control_flow_stages.go
+++ b/internal/controller/stages/control_flow_stages.go
@@ -26,6 +26,7 @@ import (
 	"github.com/akuity/kargo/internal/kubeclient"
 	libEvent "github.com/akuity/kargo/internal/kubernetes/event"
 	"github.com/akuity/kargo/internal/logging"
+	intpredicate "github.com/akuity/kargo/internal/predicate"
 )
 
 type ControlFlowStageReconciler struct {
@@ -121,6 +122,7 @@ func (r *ControlFlowStageReconciler) SetupWithManager(
 		For(&kargoapi.Stage{}).
 		Named("control_flow_stage").
 		WithOptions(controller.CommonOptions(r.cfg.MaxConcurrentControlFlowReconciles)).
+		WithEventFilter(intpredicate.IgnoreDelete[client.Object]{}).
 		WithEventFilter(
 			predicate.And(
 				IsControlFlowStage(true),
diff --git a/internal/controller/stages/regular_stages.go b/internal/controller/stages/regular_stages.go
index 5856a9566..a60472613 100644
--- a/internal/controller/stages/regular_stages.go
+++ b/internal/controller/stages/regular_stages.go
@@ -36,6 +36,7 @@ import (
 	"github.com/akuity/kargo/internal/kubeclient"
 	libEvent "github.com/akuity/kargo/internal/kubernetes/event"
 	"github.com/akuity/kargo/internal/logging"
+	intpredicate "github.com/akuity/kargo/internal/predicate"
 	"github.com/akuity/kargo/internal/rollouts"
 )
 
@@ -151,6 +152,7 @@ func (r *RegularStageReconciler) SetupWithManager(
 	c, err := ctrl.NewControllerManagedBy(kargoMgr).
 		For(&kargoapi.Stage{}).
 		WithOptions(controller.CommonOptions(r.cfg.MaxConcurrentReconciles)).
+		WithEventFilter(intpredicate.IgnoreDelete[client.Object]{}).
 		WithEventFilter(
 			predicate.And(
 				IsControlFlowStage(false),
diff --git a/internal/controller/warehouses/warehouses.go b/internal/controller/warehouses/warehouses.go
index 0ebc772c8..3a85c1fe0 100644
--- a/internal/controller/warehouses/warehouses.go
+++ b/internal/controller/warehouses/warehouses.go
@@ -10,7 +10,6 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
-	"sigs.k8s.io/controller-runtime/pkg/event"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 
@@ -24,6 +23,7 @@ import (
 	"github.com/akuity/kargo/internal/kargo"
 	"github.com/akuity/kargo/internal/kubeclient"
 	"github.com/akuity/kargo/internal/logging"
+	intpredicate "github.com/akuity/kargo/internal/predicate"
 )
 
 type ReconcilerConfig struct {
@@ -91,14 +91,7 @@ func SetupReconcilerWithManager(
 
 	if err := ctrl.NewControllerManagedBy(mgr).
 		For(&kargoapi.Warehouse{}).
-		WithEventFilter(
-			predicate.Funcs{
-				DeleteFunc: func(event.DeleteEvent) bool {
-					// We're not interested in any deletes
-					return false
-				},
-			},
-		).
+		WithEventFilter(intpredicate.IgnoreDelete[client.Object]{}).
 		WithEventFilter(
 			predicate.Or(
 				predicate.GenerationChangedPredicate{},
diff --git a/internal/predicate/ignore_delete.go b/internal/predicate/ignore_delete.go
new file mode 100644
index 000000000..a06e11388
--- /dev/null
+++ b/internal/predicate/ignore_delete.go
@@ -0,0 +1,20 @@
+package predicate
+
+import (
+	"sigs.k8s.io/controller-runtime/pkg/event"
+	"sigs.k8s.io/controller-runtime/pkg/predicate"
+)
+
+// IgnoreDelete is a predicate that filters out Delete events.
+//
+// Typically, a reconciler will not need to do anything when it receives an
+// event.TypedDeleteEvent, as it acts on the event.TypedUpdateEvent which sets
+// the deletion timestamp.
+type IgnoreDelete[T any] struct {
+	predicate.TypedFuncs[T]
+}
+
+// Delete always returns false, ignoring the event.
+func (i IgnoreDelete[T]) Delete(event.TypedDeleteEvent[T]) bool {
+	return false
+}