cleanup error handling in apiserver opts validation

cmd/kube-apiserver/app/options/validation.go

@@ -17,6 +17,7 @@ limitations under the License.
 package options
 
 import (
+	"errors"
 	"fmt"
 
 	apiextensionsapiserver "k8s.io/apiextensions-apiserver/pkg/apiserver"
@@ -28,31 +29,34 @@ import (
 
 // TODO: Longer term we should read this from some config store, rather than a flag.
 func validateClusterIPFlags(options *ServerRunOptions) []error {
-	errors := []error{}
+	var errs []error
+
 	if options.ServiceClusterIPRange.IP == nil {
-		errors = append(errors, fmt.Errorf("no --service-cluster-ip-range specified"))
+		errs = append(errs, errors.New("no --service-cluster-ip-range specified"))
 	}
 	var ones, bits = options.ServiceClusterIPRange.Mask.Size()
 	if bits-ones > 20 {
-		errors = append(errors, fmt.Errorf("specified --service-cluster-ip-range is too large"))
+		errs = append(errs, errors.New("specified --service-cluster-ip-range is too large"))
 	}
-	return errors
+
+	return errs
 }
 
 func validateServiceNodePort(options *ServerRunOptions) []error {
-	errors := []error{}
+	var errs []error
+
 	if options.KubernetesServiceNodePort < 0 || options.KubernetesServiceNodePort > 65535 {
-		errors = append(errors, fmt.Errorf("--kubernetes-service-node-port %v must be between 0 and 65535, inclusive. If 0, the Kubernetes master service will be of type ClusterIP", options.KubernetesServiceNodePort))
+		errs = append(errs, fmt.Errorf("--kubernetes-service-node-port %v must be between 0 and 65535, inclusive. If 0, the Kubernetes master service will be of type ClusterIP", options.KubernetesServiceNodePort))
 	}
 
 	if options.KubernetesServiceNodePort > 0 && !options.ServiceNodePortRange.Contains(options.KubernetesServiceNodePort) {
-		errors = append(errors, fmt.Errorf("kubernetes service port range %v doesn't contain %v", options.ServiceNodePortRange, (options.KubernetesServiceNodePort)))
+		errs = append(errs, fmt.Errorf("kubernetes service port range %v doesn't contain %v", options.ServiceNodePortRange, (options.KubernetesServiceNodePort)))
 	}
-	return errors
+	return errs
 }
 
 func validateTokenRequest(options *ServerRunOptions) []error {
-	errors := []error{}
+	var errs []error
 
 	enableAttempted := options.ServiceAccountSigningKeyFile != "" ||
 		options.Authentication.ServiceAccounts.Issuer != "" ||
@@ -61,63 +65,41 @@ func validateTokenRequest(options *ServerRunOptions) []error {
 	enableSucceeded := options.ServiceAccountIssuer != nil
 
 	if enableAttempted && !utilfeature.DefaultFeatureGate.Enabled(features.TokenRequest) {
-		errors = append(errors, fmt.Errorf("the TokenRequest feature is not enabled but --service-account-signing-key-file, --service-account-issuer and/or --api-audiences flags were passed"))
+		errs = append(errs, errors.New("the TokenRequest feature is not enabled but --service-account-signing-key-file, --service-account-issuer and/or --api-audiences flags were passed"))
 	}
 
 	if utilfeature.DefaultFeatureGate.Enabled(features.BoundServiceAccountTokenVolume) && !utilfeature.DefaultFeatureGate.Enabled(features.TokenRequest) {
-		errors = append(errors, fmt.Errorf("the BoundServiceAccountTokenVolume feature depends on the TokenRequest feature, but the TokenRequest features is not enabled"))
+		errs = append(errs, errors.New("the BoundServiceAccountTokenVolume feature depends on the TokenRequest feature, but the TokenRequest features is not enabled"))
 	}
 
 	if !enableAttempted && utilfeature.DefaultFeatureGate.Enabled(features.BoundServiceAccountTokenVolume) {
-		errors = append(errors, fmt.Errorf("--service-account-signing-key-file and --service-account-issuer are required flags"))
+		errs = append(errs, errors.New("--service-account-signing-key-file and --service-account-issuer are required flags"))
 	}
 
 	if enableAttempted && !enableSucceeded {
-		errors = append(errors, fmt.Errorf("--service-account-signing-key-file, --service-account-issuer, and --api-audiences should be specified together"))
+		errs = append(errs, errors.New("--service-account-signing-key-file, --service-account-issuer, and --api-audiences should be specified together"))
 	}
 
-	return errors
+	return errs
 }
 
-// Validate checks ServerRunOptions and return a slice of found errors.
+// Validate checks ServerRunOptions and return a slice of found errs.
 func (s *ServerRunOptions) Validate() []error {
-	var errors []error
-	if errs := s.Etcd.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := validateClusterIPFlags(s); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := validateServiceNodePort(s); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.SecureServing.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.Authentication.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.Authorization.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.Audit.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.Admission.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := s.InsecureServing.Validate(); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
+	var errs []error
 	if s.MasterCount <= 0 {
-		errors = append(errors, fmt.Errorf("--apiserver-count should be a positive number, but value '%d' provided", s.MasterCount))
-	}
-	if errs := s.APIEnablement.Validate(legacyscheme.Scheme, apiextensionsapiserver.Scheme, aggregatorscheme.Scheme); len(errs) > 0 {
-		errors = append(errors, errs...)
-	}
-	if errs := validateTokenRequest(s); len(errs) > 0 {
-		errors = append(errors, errs...)
+		errs = append(errs, fmt.Errorf("--apiserver-count should be a positive number, but value '%d' provided", s.MasterCount))
 	}
+	errs = append(errs, s.Etcd.Validate()...)
+	errs = append(errs, validateClusterIPFlags(s)...)
+	errs = append(errs, validateServiceNodePort(s)...)
+	errs = append(errs, s.SecureServing.Validate()...)
+	errs = append(errs, s.Authentication.Validate()...)
+	errs = append(errs, s.Authorization.Validate()...)
+	errs = append(errs, s.Audit.Validate()...)
+	errs = append(errs, s.Admission.Validate()...)
+	errs = append(errs, s.InsecureServing.Validate()...)
+	errs = append(errs, s.APIEnablement.Validate(legacyscheme.Scheme, apiextensionsapiserver.Scheme, aggregatorscheme.Scheme)...)
+	errs = append(errs, validateTokenRequest(s)...)
 
-	return errors
+	return errs
 }