chore: add secrets cache

Signed-off-by: Armando Ruocco <[email protected]>

Author: armru

internal/client/client.go

@@ -0,0 +1,74 @@
+package client
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	corev1 "k8s.io/api/core/v1"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+)
+
+type cachedSecret struct {
+	secret        *corev1.Secret
+	fetchUnixTime int64
+}
+
+type extendedClient struct {
+	client.Client
+	cachedSecrets []*cachedSecret
+	// add a mux to lock the operations on the cache
+	mux *sync.Mutex
+}
+
+// NewExtendedClient returns an extended client capable of caching secrets on the 'Get' operation
+func NewExtendedClient(baseClient client.Client) client.Client {
+	return &extendedClient{
+		Client: baseClient,
+	}
+}
+
+func (e *extendedClient) Get(ctx context.Context, key client.ObjectKey, obj client.Object, opts ...client.GetOption) error {
+	// if not secret use the get from the base client
+	if _, ok := obj.(*corev1.Secret); !ok {
+		return e.Client.Get(ctx, key, obj, opts...)
+	}
+
+	// grab the lock if we get here
+	e.mux.Lock()
+	defer e.mux.Unlock()
+	// check if in cache
+	for _, cache := range e.cachedSecrets {
+		if cache.secret.Namespace == key.Namespace && cache.secret.Name == key.Name {
+			if time.Now().Unix()-cache.fetchUnixTime < 180 {
+				cache.secret.DeepCopyInto(obj.(*corev1.Secret))
+				return nil
+			}
+			break
+		}
+	}
+
+	if err := e.Client.Get(ctx, key, obj); err != nil {
+		return err
+	}
+
+	// check if the secret is already in cache if so replace it
+	for _, cache := range e.cachedSecrets {
+		if cache.secret.Namespace == key.Namespace && cache.secret.Name == key.Name {
+			cache.secret = obj.(*corev1.Secret)
+			cache.fetchUnixTime = time.Now().Unix()
+			return nil
+		}
+	}
+
+	if secret, ok := obj.(*corev1.Secret); ok {
+		e.cachedSecrets = append(e.cachedSecrets, &cachedSecret{
+			secret:        secret,
+			fetchUnixTime: time.Now().Unix(),
+		})
+	}
+	// unlock
+	e.mux.Unlock()
+
+	return nil
+}

internal/client/doc.go

@@ -0,0 +1,3 @@
+// Package client provides an extended  client that is capable of caching multiple secrets without relying on
+// 'list and watch'
+package client