Merge pull request #3353 from thockin/errors

Cleaner aggregate errors API

pkg/api/errors/errors.go

@@ -22,7 +22,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 // StatusError is an error intended for consumption by a REST API server; it can also be
@@ -141,7 +141,7 @@ func NewInvalid(kind, name string, errs ValidationErrorList) error {
 			ID:     name,
 			Causes: causes,
 		},
-		Message: fmt.Sprintf("%s %q is invalid: %v", kind, name, util.SliceToError(errs)),
+		Message: fmt.Sprintf("%s %q is invalid: %v", kind, name, errors.NewAggregate(errs)),
 	}}
 }
 

pkg/api/validation/validation_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/capabilities"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/registry/registrytest"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	utilerrors "github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 func expectPrefix(t *testing.T, prefix string, errs errors.ValidationErrorList) {
@@ -968,7 +969,7 @@ func TestValidateService(t *testing.T) {
 		registry.List = tc.existing
 		errs := ValidateService(&tc.svc, registry, api.NewDefaultContext())
 		if len(errs) != tc.numErrs {
-			t.Errorf("Unexpected error list for case %q: %v", tc.name, util.SliceToError(errs))
+			t.Errorf("Unexpected error list for case %q: %v", tc.name, utilerrors.NewAggregate(errs))
 		}
 	}
 

pkg/client/clientcmd/client_config.go

@@ -24,7 +24,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/client"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/clientauth"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 var (
@@ -227,7 +227,7 @@ func (config DirectClientConfig) ConfirmUsable() error {
 	validationErrors = append(validationErrors, validateAuthInfo(config.getAuthInfoName(), config.getAuthInfo())...)
 	validationErrors = append(validationErrors, validateClusterInfo(config.getClusterName(), config.getCluster())...)
 
-	return util.SliceToError(validationErrors)
+	return errors.NewAggregate(validationErrors)
 }
 
 func (config DirectClientConfig) getContextName() string {

pkg/client/clientcmd/validation.go

@@ -23,6 +23,7 @@ import (
 	"strings"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	utilerrors "github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 var ErrNoContext = errors.New("no context chosen")
@@ -67,7 +68,7 @@ func Validate(config Config) error {
 		validationErrors = append(validationErrors, validateClusterInfo(clusterName, clusterInfo)...)
 	}
 
-	return util.SliceToError(validationErrors)
+	return utilerrors.NewAggregate(validationErrors)
 }
 
 // ConfirmUsable looks a particular context and determines if that particular part of the config is useable.  There might still be errors in the config,
@@ -97,7 +98,7 @@ func ConfirmUsable(config Config, passedContextName string) error {
 		validationErrors = append(validationErrors, validateClusterInfo(context.Cluster, config.Clusters[context.Cluster])...)
 	}
 
-	return util.SliceToError(validationErrors)
+	return utilerrors.NewAggregate(validationErrors)
 }
 
 // validateClusterInfo looks for conflicts and errors in the cluster info

pkg/client/clientcmd/validation_test.go

@@ -22,7 +22,7 @@ import (
 	"strings"
 	"testing"
 
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 func TestConfirmUsableBadInfoButOkConfig(t *testing.T) {
@@ -300,14 +300,14 @@ func (c configValidationTest) testContext(contextName string, t *testing.T) {
 			t.Errorf("Expected error containing: %v", c.expectedErrorSubstring)
 		}
 		for _, curr := range c.expectedErrorSubstring {
-			if len(errs) != 0 && !strings.Contains(util.SliceToError(errs).Error(), curr) {
+			if len(errs) != 0 && !strings.Contains(errors.NewAggregate(errs).Error(), curr) {
-				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, util.SliceToError(errs))
+				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, errors.NewAggregate(errs))
 			}
 		}
 
 	} else {
 		if len(errs) != 0 {
-			t.Errorf("Unexpected error: %v", util.SliceToError(errs))
+			t.Errorf("Unexpected error: %v", errors.NewAggregate(errs))
 		}
 	}
 }
@@ -357,14 +357,14 @@ func (c configValidationTest) testCluster(clusterName string, t *testing.T) {
 			t.Errorf("Expected error containing: %v", c.expectedErrorSubstring)
 		}
 		for _, curr := range c.expectedErrorSubstring {
-			if len(errs) != 0 && !strings.Contains(util.SliceToError(errs).Error(), curr) {
+			if len(errs) != 0 && !strings.Contains(errors.NewAggregate(errs).Error(), curr) {
-				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, util.SliceToError(errs))
+				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, errors.NewAggregate(errs))
 			}
 		}
 
 	} else {
 		if len(errs) != 0 {
-			t.Errorf("Unexpected error: %v", util.SliceToError(errs))
+			t.Errorf("Unexpected error: %v", errors.NewAggregate(errs))
 		}
 	}
 }
@@ -377,14 +377,14 @@ func (c configValidationTest) testAuthInfo(authInfoName string, t *testing.T) {
 			t.Errorf("Expected error containing: %v", c.expectedErrorSubstring)
 		}
 		for _, curr := range c.expectedErrorSubstring {
-			if len(errs) != 0 && !strings.Contains(util.SliceToError(errs).Error(), curr) {
+			if len(errs) != 0 && !strings.Contains(errors.NewAggregate(errs).Error(), curr) {
-				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, util.SliceToError(errs))
+				t.Errorf("Expected error containing: %v, but got %v", c.expectedErrorSubstring, errors.NewAggregate(errs))
 			}
 		}
 
 	} else {
 		if len(errs) != 0 {
-			t.Errorf("Unexpected error: %v", util.SliceToError(errs))
+			t.Errorf("Unexpected error: %v", errors.NewAggregate(errs))
 		}
 	}
 }

pkg/proxy/proxier.go

@@ -27,6 +27,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/iptables"
 	"github.com/golang/glog"
 )
@@ -575,7 +576,7 @@ func (proxier *Proxier) closePortal(service string, info *serviceInfo) error {
 	} else {
 		glog.Errorf("Some errors closing iptables portals for service %q", service)
 	}
-	return util.SliceToError(el)
+	return errors.NewAggregate(el)
 }
 
 func (proxier *Proxier) closeOnePortal(portalIP net.IP, portalPort int, protocol api.Protocol, proxyIP net.IP, proxyPort int, name string) []error {
@@ -646,7 +647,7 @@ func iptablesFlush(ipt iptables.Interface) error {
 	if len(el) != 0 {
 		glog.Errorf("Some errors flushing old iptables portals: %v", el)
 	}
-	return util.SliceToError(el)
+	return errors.NewAggregate(el)
 }
 
 // Used below.

pkg/util/error_list.go

@@ -1,54 +0,0 @@
-/*
-Copyright 2014 Google Inc. All rights reserved.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package util
-
-import (
-	"fmt"
-)
-
-// []error is a collection of errors. This does not implement the error
-// interface to avoid confusion where an empty []error would still be an
-// error (non-nil).  To produce a single error instance from an []error, use
-// the SliceToError() method, which will return nil for an empty []error.
-
-// This helper implements the error interface for []error, but prevents
-// accidental conversion of []error to error.
-type errorList []error
-
-// Error is part of the error interface.
-func (list errorList) Error() string {
-	if len(list) == 0 {
-		return ""
-	}
-	if len(list) == 1 {
-		return list[0].Error()
-	}
-	result := fmt.Sprintf("[%s", list[0].Error())
-	for i := 1; i < len(list); i++ {
-		result += fmt.Sprintf(", %s", list[i].Error())
-	}
-	result += "]"
-	return result
-}
-
-// SliceToError converts an []error into a "normal" error, or nil if the slice is empty.
-func SliceToError(errs []error) error {
-	if len(errs) == 0 {
-		return nil
-	}
-	return errorList(errs)
-}

pkg/util/error_list_test.go

@@ -1,51 +0,0 @@
-/*
-Copyright 2014 Google Inc. All rights reserved.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package util
-
-import (
-	"fmt"
-	"testing"
-)
-
-func TestErrorList(t *testing.T) {
-	var errList []error
-	err := SliceToError(errList)
-	if err != nil {
-		t.Errorf("expected nil, got %v", err)
-	}
-	if a := errorList(errList).Error(); a != "" {
-		t.Errorf("expected empty string, got %q", a)
-	}
-
-	testCases := []struct {
-		errs     []error
-		expected string
-	}{
-		{[]error{fmt.Errorf("abc")}, "abc"},
-		{[]error{fmt.Errorf("abc"), fmt.Errorf("123")}, "[abc, 123]"},
-	}
-	for _, testCase := range testCases {
-		err := SliceToError(testCase.errs)
-		if err == nil {
-			t.Errorf("expected an error, got nil: %v", testCase)
-			continue
-		}
-		if err.Error() != testCase.expected {
-			t.Errorf("expected %q, got %q", testCase.expected, err.Error())
-		}
-	}
-}

pkg/util/errors/doc.go

@@ -0,0 +1,18 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+// Package errors implements various utility functions and types around errors.
+package errors

pkg/util/errors/errors.go

@@ -0,0 +1,133 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package errors
+
+import "fmt"
+
+// Aggregate represents an object that contains multiple errors, but does not
+// necessarily have singular semantic meaning.
+type Aggregate interface {
+	error
+	Errors() []error
+}
+
+// NewAggregate converts a slice of errors into an Aggregate interface, which
+// is itself an implementation of the error interface.  If the slice is empty,
+// this returs nil.
+func NewAggregate(errlist []error) Aggregate {
+	if len(errlist) == 0 {
+		return nil
+	}
+	return aggregate(errlist)
+}
+
+// This helper implements the error and Errors interfaces.  Keeping it private
+// prevents people from making an aggregate of 0 errors, which is not
+// an error, but does satisfy the error interface.
+type aggregate []error
+
+// Error is part of the error interface.
+func (agg aggregate) Error() string {
+	if len(agg) == 0 {
+		// This should never happen, really.
+		return ""
+	}
+	if len(agg) == 1 {
+		return agg[0].Error()
+	}
+	result := fmt.Sprintf("[%s", agg[0].Error())
+	for i := 1; i < len(agg); i++ {
+		result += fmt.Sprintf(", %s", agg[i].Error())
+	}
+	result += "]"
+	return result
+}
+
+// Errors is part of the Aggregate interface.
+func (agg aggregate) Errors() []error {
+	return []error(agg)
+}
+
+// Matcher is used to match errors.  Returns true if the error matches.
+type Matcher func(error) bool
+
+// FilterOut removes all errors that match any of the matchers from the input
+// error.  If the input is a singular error, only that error is tested.  If the
+// input implements the Aggregate interface, the list of errors will be
+// processed recursively.
+//
+// This can be used, for example, to remove known-OK errors (such as io.EOF or
+// os.PathNotFound) from a list of errors.
+func FilterOut(err error, fns ...Matcher) error {
+	if err == nil {
+		return nil
+	}
+	if agg, ok := err.(Aggregate); ok {
+		return NewAggregate(filterErrors(agg.Errors(), fns...))
+	}
+	if !matchesError(err, fns...) {
+		return err
+	}
+	return nil
+}
+
+// matchesError returns true if any Matcher returns true
+func matchesError(err error, fns ...Matcher) bool {
+	for _, fn := range fns {
+		if fn(err) {
+			return true
+		}
+	}
+	return false
+}
+
+// filterErrors returns any errors (or nested errors, if the list contains
+// nested Errors) for which all fns return false. If no errors
+// remain a nil list is returned. The resulting silec will have all
+// nested slices flattened as a side effect.
+func filterErrors(list []error, fns ...Matcher) []error {
+	result := []error{}
+	for _, err := range list {
+		r := FilterOut(err, fns...)
+		if r != nil {
+			result = append(result, r)
+		}
+	}
+	return result
+}
+
+// Flatten takes an Aggregate, which may hold other Aggregates in arbitrary
+// nesting, and flattens them all into a single Aggregate, recursively.
+func Flatten(agg Aggregate) Aggregate {
+	result := []error{}
+	if agg == nil {
+		return nil
+	}
+	for _, err := range agg.Errors() {
+		if a, ok := err.(Aggregate); ok {
+			r := Flatten(a)
+			if r != nil {
+				result = append(result, r.Errors()...)
+			}
+		} else {
+			if err != nil {
+				result = append(result, err)
+			}
+		}
+	}
+	return NewAggregate(result)
+}

pkg/util/errors/errors_test.go

@@ -0,0 +1,223 @@
+/*
+Copyright 2015 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package errors
+
+import (
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestEmptyAggregate(t *testing.T) {
+	var slice []error
+	var agg Aggregate
+	var err error
+
+	agg = NewAggregate(slice)
+	if agg != nil {
+		t.Errorf("expected nil, got %#v", agg)
+	}
+	err = NewAggregate(slice)
+	if err != nil {
+		t.Errorf("expected nil, got %#v", err)
+	}
+
+	// This is not normally possible, but pedantry demands I test it.
+	agg = aggregate(slice) // empty aggregate
+	if s := agg.Error(); s != "" {
+		t.Errorf("expected empty string, got %q", s)
+	}
+	if s := agg.Errors(); len(s) != 0 {
+		t.Errorf("expected empty slice, got %#v", s)
+	}
+	err = agg.(error)
+	if s := err.Error(); s != "" {
+		t.Errorf("expected empty string, got %q", s)
+	}
+}
+
+func TestSingularAggregate(t *testing.T) {
+	var slice []error = []error{fmt.Errorf("err")}
+	var agg Aggregate
+	var err error
+
+	agg = NewAggregate(slice)
+	if agg == nil {
+		t.Errorf("expected non-nil")
+	}
+	if s := agg.Error(); s != "err" {
+		t.Errorf("expected 'err', got %q", s)
+	}
+	if s := agg.Errors(); len(s) != 1 {
+		t.Errorf("expected one-element slice, got %#v", s)
+	}
+	if s := agg.Errors()[0].Error(); s != "err" {
+		t.Errorf("expected 'err', got %q", s)
+	}
+
+	err = agg.(error)
+	if err == nil {
+		t.Errorf("expected non-nil")
+	}
+	if s := err.Error(); s != "err" {
+		t.Errorf("expected 'err', got %q", s)
+	}
+}
+
+func TestPluralAggregate(t *testing.T) {
+	var slice []error = []error{fmt.Errorf("abc"), fmt.Errorf("123")}
+	var agg Aggregate
+	var err error
+
+	agg = NewAggregate(slice)
+	if agg == nil {
+		t.Errorf("expected non-nil")
+	}
+	if s := agg.Error(); s != "[abc, 123]" {
+		t.Errorf("expected '[abc, 123]', got %q", s)
+	}
+	if s := agg.Errors(); len(s) != 2 {
+		t.Errorf("expected one-element slice, got %#v", s)
+	}
+	if s := agg.Errors()[0].Error(); s != "abc" {
+		t.Errorf("expected '[abc, 123]', got %q", s)
+	}
+
+	err = agg.(error)
+	if err == nil {
+		t.Errorf("expected non-nil")
+	}
+	if s := err.Error(); s != "[abc, 123]" {
+		t.Errorf("expected '[abc, 123]', got %q", s)
+	}
+}
+
+func TestFilterOut(t *testing.T) {
+	testCases := []struct {
+		err      error
+		filter   []Matcher
+		expected error
+	}{
+		{
+			nil,
+			[]Matcher{},
+			nil,
+		},
+		{
+			aggregate{},
+			[]Matcher{},
+			nil,
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			[]Matcher{},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			[]Matcher{func(err error) bool { return false }},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			[]Matcher{func(err error) bool { return true }},
+			nil,
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			[]Matcher{func(err error) bool { return false }, func(err error) bool { return false }},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			[]Matcher{func(err error) bool { return false }, func(err error) bool { return true }},
+			nil,
+		},
+		{
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("def"), fmt.Errorf("ghi")},
+			[]Matcher{func(err error) bool { return err.Error() == "def" }},
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("ghi")},
+		},
+		{
+			aggregate{aggregate{fmt.Errorf("abc")}},
+			[]Matcher{},
+			aggregate{aggregate{fmt.Errorf("abc")}},
+		},
+		{
+			aggregate{aggregate{fmt.Errorf("abc"), aggregate{fmt.Errorf("def")}}},
+			[]Matcher{},
+			aggregate{aggregate{fmt.Errorf("abc"), aggregate{fmt.Errorf("def")}}},
+		},
+		{
+			aggregate{aggregate{fmt.Errorf("abc"), aggregate{fmt.Errorf("def")}}},
+			[]Matcher{func(err error) bool { return err.Error() == "def" }},
+			aggregate{aggregate{fmt.Errorf("abc")}},
+		},
+	}
+	for i, testCase := range testCases {
+		err := FilterOut(testCase.err, testCase.filter...)
+		if !reflect.DeepEqual(testCase.expected, err) {
+			t.Errorf("%d: expected %v, got %v", i, testCase.expected, err)
+		}
+	}
+}
+
+func TestFlatten(t *testing.T) {
+	testCases := []struct {
+		agg      Aggregate
+		expected Aggregate
+	}{
+		{
+			nil,
+			nil,
+		},
+		{
+			aggregate{},
+			nil,
+		},
+		{
+			aggregate{fmt.Errorf("abc")},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("def"), fmt.Errorf("ghi")},
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("def"), fmt.Errorf("ghi")},
+		},
+		{
+			aggregate{aggregate{fmt.Errorf("abc")}},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{aggregate{aggregate{fmt.Errorf("abc")}}},
+			aggregate{fmt.Errorf("abc")},
+		},
+		{
+			aggregate{aggregate{fmt.Errorf("abc"), aggregate{fmt.Errorf("def")}}},
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("def")},
+		},
+		{
+			aggregate{aggregate{aggregate{fmt.Errorf("abc")}, fmt.Errorf("def"), aggregate{fmt.Errorf("ghi")}}},
+			aggregate{fmt.Errorf("abc"), fmt.Errorf("def"), fmt.Errorf("ghi")},
+		},
+	}
+	for i, testCase := range testCases {
+		agg := Flatten(testCase.agg)
+		if !reflect.DeepEqual(testCase.expected, agg) {
+			t.Errorf("%d: expected %v, got %v", i, testCase.expected, agg)
+		}
+	}
+}

plugin/pkg/auth/authenticator/request/union/union.go

@@ -21,7 +21,7 @@ import (
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/authenticator"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/user"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 // unionAuthRequestHandler authenticates requests using a chain of authenticator.Requests
@@ -35,11 +35,11 @@ func New(authRequestHandlers ...authenticator.Request) authenticator.Request {
 // AuthenticateRequest authenticates the request using a chain of authenticator.Request objects.  The first
 // success returns that identity.  Errors are only returned if no matches are found.
 func (authHandler unionAuthRequestHandler) AuthenticateRequest(req *http.Request) (user.Info, bool, error) {
-	var errors []error
+	var errlist []error
 	for _, currAuthRequestHandler := range authHandler {
 		info, ok, err := currAuthRequestHandler.AuthenticateRequest(req)
 		if err != nil {
-			errors = append(errors, err)
+			errlist = append(errlist, err)
 			continue
 		}
 
@@ -48,5 +48,5 @@ func (authHandler unionAuthRequestHandler) AuthenticateRequest(req *http.Request
 		}
 	}
 
-	return nil, false, util.SliceToError(errors)
+	return nil, false, errors.NewAggregate(errlist)
 }

plugin/pkg/auth/authenticator/request/x509/x509.go

@@ -21,7 +21,7 @@ import (
 	"net/http"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/auth/user"
-	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/util/errors"
 )
 
 // UserConversion defines an interface for extracting user info from a client certificate chain
@@ -55,18 +55,18 @@ func (a *Authenticator) AuthenticateRequest(req *http.Request) (user.Info, bool,
 		return nil, false, nil
 	}
 
-	var errors []error
+	var errlist []error
 	for _, cert := range req.TLS.PeerCertificates {
 		chains, err := cert.Verify(a.opts)
 		if err != nil {
-			errors = append(errors, err)
+			errlist = append(errlist, err)
 			continue
 		}
 
 		for _, chain := range chains {
 			user, ok, err := a.user.User(chain)
 			if err != nil {
-				errors = append(errors, err)
+				errlist = append(errlist, err)
 				continue
 			}
 
@@ -75,7 +75,7 @@ func (a *Authenticator) AuthenticateRequest(req *http.Request) (user.Info, bool,
 			}
 		}
 	}
-	return nil, false, util.SliceToError(errors)
+	return nil, false, errors.NewAggregate(errlist)
 }
 
 // DefaultVerifyOptions returns VerifyOptions that use the system root certificates, current time,