feat(appset): Add a cache layer for Argo Projects to speed-up applica…

…tion validation

applicationset/controllers/applicationset_controller.go

@@ -55,6 +55,7 @@ import (
 	"github.com/argoproj/argo-cd/v2/util/argo/normalizers"
 
 	"github.com/argoproj/argo-cd/v2/pkg/apis/application"
+	"github.com/hashicorp/golang-lru/v2/expirable"
 )
 
 const (
@@ -95,6 +96,7 @@ type ApplicationSetReconciler struct {
 // +kubebuilder:rbac:groups=argoproj.io,resources=applicationsets/status,verbs=get;update;patch
 
 func (r *ApplicationSetReconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Result, error) {
+	startReconcile := time.Now()
 	logCtx := log.WithField("applicationset", req.NamespacedName)
 
 	var applicationSetInfo argov1alpha1.ApplicationSet
@@ -337,7 +339,7 @@ func (r *ApplicationSetReconciler) Reconcile(ctx context.Context, req ctrl.Reque
 		requeueAfter = ReconcileRequeueOnValidationError
 	}
 
-	logCtx.WithField("requeueAfter", requeueAfter).Info("end reconcile")
+	logCtx.WithField("requeueAfter", requeueAfter).Info("end reconcile in ", time.Since(startReconcile))
 
 	return ctrl.Result{
 		RequeueAfter: requeueAfter,
@@ -446,6 +448,9 @@ func (r *ApplicationSetReconciler) setApplicationSetStatusCondition(ctx context.
 	return nil
 }
 
+// TODO add an option to choose cache expiration
+var argoProjCache = expirable.NewLRU[string, bool](0, nil, time.Hour*24)
+
 // validateGeneratedApplications uses the Argo CD validation functions to verify the correctness of the
 // generated applications.
 func (r *ApplicationSetReconciler) validateGeneratedApplications(ctx context.Context, desiredApplications []argov1alpha1.Application, applicationSetInfo argov1alpha1.ApplicationSet) (map[int]error, error) {
@@ -458,13 +463,18 @@ func (r *ApplicationSetReconciler) validateGeneratedApplications(ctx context.Con
 			errorsByIndex[i] = fmt.Errorf("ApplicationSet %s contains applications with duplicate name: %s", applicationSetInfo.Name, app.Name)
 			continue
 		}
-		_, err := r.ArgoAppClientset.ArgoprojV1alpha1().AppProjects(r.ArgoCDNamespace).Get(ctx, app.Spec.GetProject(), metav1.GetOptions{})
-		if err != nil {
-			if apierr.IsNotFound(err) {
-				errorsByIndex[i] = fmt.Errorf("application references project %s which does not exist", app.Spec.Project)
-				continue
+
+		if !argoProjCache.Contains(app.Spec.GetProject()) {
+			_, err := r.ArgoAppClientset.ArgoprojV1alpha1().AppProjects(r.ArgoCDNamespace).Get(ctx, app.Spec.GetProject(), metav1.GetOptions{})
+			if err != nil {
+				if apierr.IsNotFound(err) {
+					errorsByIndex[i] = fmt.Errorf("application references project %s which does not exist", app.Spec.Project)
+					continue
+				}
+				return nil, err
+			} else {
+				argoProjCache.Add(app.Spec.GetProject(), true)
 			}
-			return nil, err
 		}
 
 		if err := utils.ValidateDestination(ctx, &app.Spec.Destination, r.KubeClientset, r.ArgoCDNamespace); err != nil {

go.mod

@@ -53,6 +53,7 @@ require (
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/grpc-ecosystem/grpc-gateway v1.16.0
 	github.com/hashicorp/go-retryablehttp v0.7.4
+	github.com/hashicorp/golang-lru/v2 v2.0.7
 	github.com/imdario/mergo v0.3.16
 	github.com/improbable-eng/grpc-web v0.15.0
 	github.com/itchyny/gojq v0.12.13

go.sum

@@ -1261,6 +1261,8 @@ github.com/hashicorp/go-version v1.6.0/go.mod h1:fltr4n8CU8Ke44wwGCBoEymUuxUHl09
 github.com/hashicorp/go.net v0.0.1/go.mod h1:hjKkEWcCURg++eb33jQU7oqQcI9XDCnUzHA0oac0k90=
 github.com/hashicorp/golang-lru v0.5.0/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
 github.com/hashicorp/golang-lru v0.5.1/go.mod h1:/m3WP610KZHVQ1SGc6re/UDhFvYD7pJ4Ao+sR/qLZy8=
+github.com/hashicorp/golang-lru/v2 v2.0.7 h1:a+bsQ5rvGLjzHuww6tVxozPZFVghXaHOwFs4luLUK2k=
+github.com/hashicorp/golang-lru/v2 v2.0.7/go.mod h1:QeFd9opnmA6QUJc5vARoKUSoFhyfM2/ZepoAG6RGpeM=
 github.com/hashicorp/logutils v1.0.0/go.mod h1:QIAnNjmIWmVIIkWDTG1z5v++HQmx9WQRO+LraFDTW64=
 github.com/hashicorp/mdns v1.0.0/go.mod h1:tL+uN++7HEJ6SQLQ2/p+z2pH24WQKWjBPkE0mNTz8vQ=
 github.com/hashicorp/memberlist v0.1.3/go.mod h1:ajVTdAv/9Im8oMAAj5G31PhhMCZJV2pPBoIllUwCN7I=