Reduce the amount of API calls to k8s API server to fetch secrets

Signed-off-by: Joyce Yee <[email protected]>

metricproviders/datadog/datadog.go

@@ -18,6 +18,7 @@ import (
 	"github.com/argoproj/argo-rollouts/utils/evaluate"
 	metricutil "github.com/argoproj/argo-rollouts/utils/metric"
 	log "github.com/sirupsen/logrus"
+	v1 "k8s.io/api/core/v1"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/client-go/kubernetes"
 )
@@ -167,34 +168,34 @@ func (p *Provider) GarbageCollect(run *v1alpha1.AnalysisRun, metric v1alpha1.Met
 	return nil
 }
 
-func getSecretValue(key, ns string, kubeclientset kubernetes.Interface, emptyValueOk bool) (string, error) {
+func getSecretValue(key string, k8sSecret *v1.Secret, emptyValueOk bool) (string, error) {
 	envKey := strings.ToUpper(strings.ReplaceAll(key, "-", "_"))
 	if value, ok := os.LookupEnv(fmt.Sprintf("DD_%s", envKey)); ok {
 		return value, nil
 	}
-	secret, err := kubeclientset.CoreV1().Secrets(ns).Get(context.TODO(), DatadogTokensSecretName, metav1.GetOptions{})
-	if err != nil {
-		return "", err
-	}
-	_, valueMaybe := secret.Data[key]
+	_, valueMaybe := k8sSecret.Data[key]
 	if emptyValueOk && !valueMaybe {
 		return "", nil
 	}
 
-	return string(secret.Data[key]), nil
+	return string(k8sSecret.Data[key]), nil
 }
 
 func NewDatadogProvider(logCtx log.Entry, kubeclientset kubernetes.Interface) (*Provider, error) {
 	ns := defaults.Namespace()
-	apiKey, err := getSecretValue("api-key", ns, kubeclientset, false)
+	secret, err := kubeclientset.CoreV1().Secrets(ns).Get(context.TODO(), DatadogTokensSecretName, metav1.GetOptions{})
+	if err != nil {
+		return nil, err
+	}
+	apiKey, err := getSecretValue("api-key", secret, false)
 	if err != nil {
 		return nil, err
 	}
-	appKey, err := getSecretValue("app-key", ns, kubeclientset, false)
+	appKey, err := getSecretValue("app-key", secret, false)
 	if err != nil {
 		return nil, err
 	}
-	address, err := getSecretValue("address", ns, kubeclientset, true)
+	address, err := getSecretValue("address", secret, true)
 	if err != nil {
 		return nil, err
 	}