Extract helper for continue handling

This commit is contained in:
Katrina Verey 2021-03-19 08:31:55 -07:00
parent f8097c6cee
commit c56be1fa9f
3 changed files with 239 additions and 38 deletions

View File

@ -18,9 +18,12 @@ package resource
import (
"context"
"fmt"
apierrors "k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/meta"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/fields"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/types"
@ -90,6 +93,54 @@ func (m *Helper) List(namespace, apiVersion string, options *metav1.ListOptions)
return req.Do(context.TODO()).Get()
}
// FollowContinue handles the continue parameter returned by the API server when using list
// chunking. To take advantage of this, the initial ListOptions provided by the consumer
// should include a non-zero Limit parameter.
func FollowContinue(initialOpts *metav1.ListOptions,
listFunc func(metav1.ListOptions) (runtime.Object, error)) error {
opts := initialOpts
for {
list, err := listFunc(*opts)
if err != nil {
return err
}
nextContinueToken, _ := metadataAccessor.Continue(list)
if len(nextContinueToken) == 0 {
return nil
}
opts.Continue = nextContinueToken
}
}
// EnhanceListError augments errors typically returned by List operations with additional context,
// making sure to retain the StatusError type when applicable.
func EnhanceListError(err error, opts metav1.ListOptions, subj string) error {
if apierrors.IsResourceExpired(err) {
return err
}
if apierrors.IsBadRequest(err) || apierrors.IsNotFound(err) {
if se, ok := err.(*apierrors.StatusError); ok {
// modify the message without hiding this is an API error
if len(opts.LabelSelector) == 0 && len(opts.FieldSelector) == 0 {
se.ErrStatus.Message = fmt.Sprintf("Unable to list %q: %v", subj,
se.ErrStatus.Message)
} else {
se.ErrStatus.Message = fmt.Sprintf(
"Unable to find %q that match label selector %q, field selector %q: %v", subj,
opts.LabelSelector,
opts.FieldSelector, se.ErrStatus.Message)
}
return se
}
if len(opts.LabelSelector) == 0 && len(opts.FieldSelector) == 0 {
return fmt.Errorf("Unable to list %q: %v", subj, err)
}
return fmt.Errorf("Unable to find %q that match label selector %q, field selector %q: %v",
subj, opts.LabelSelector, opts.FieldSelector, err)
}
return err
}
func (m *Helper) Watch(namespace, apiVersion string, options *metav1.ListOptions) (watch.Interface, error) {
options.Watch = true
return m.RESTClient.Get().

View File

@ -19,6 +19,7 @@ package resource
import (
"bytes"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
@ -26,6 +27,7 @@ import (
"strings"
"testing"
apierrors "k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/runtime"
@ -628,3 +630,174 @@ func TestHelperReplace(t *testing.T) {
})
}
}
func TestEnhanceListError(t *testing.T) {
podGVR := corev1.SchemeGroupVersion.WithResource(corev1.ResourcePods.String())
podSubject := podGVR.String()
tests := []struct {
name string
err error
opts metav1.ListOptions
subj string
expectedErr string
expectStatusErr bool
}{
{
name: "leaves resource expired error as is",
err: apierrors.NewResourceExpired("resourceversion too old"),
opts: metav1.ListOptions{},
subj: podSubject,
expectedErr: "resourceversion too old",
expectStatusErr: true,
}, {
name: "leaves unrecognized error as is",
err: errors.New("something went wrong"),
opts: metav1.ListOptions{},
subj: podSubject,
expectedErr: "something went wrong",
expectStatusErr: false,
}, {
name: "bad request StatusError without selectors",
err: apierrors.NewBadRequest("request is invalid"),
opts: metav1.ListOptions{},
subj: podSubject,
expectedErr: "Unable to list \"/v1, Resource=pods\": request is invalid",
expectStatusErr: true,
}, {
name: "bad request StatusError with selectors",
err: apierrors.NewBadRequest("request is invalid"),
opts: metav1.ListOptions{
LabelSelector: "a=b",
FieldSelector: ".spec.nodeName=foo",
},
subj: podSubject,
expectedErr: "Unable to find \"/v1, Resource=pods\" that match label selector \"a=b\", field selector \".spec.nodeName=foo\": request is invalid",
expectStatusErr: true,
}, {
name: "not found without selectors",
err: apierrors.NewNotFound(podGVR.GroupResource(), "foo"),
opts: metav1.ListOptions{},
subj: podSubject,
expectedErr: "Unable to list \"/v1, Resource=pods\": pods \"foo\" not found",
expectStatusErr: true,
}, {
name: "not found StatusError with selectors",
err: apierrors.NewNotFound(podGVR.GroupResource(), "foo"),
opts: metav1.ListOptions{
LabelSelector: "a=b",
FieldSelector: ".spec.nodeName=foo",
},
subj: podSubject,
expectedErr: "Unable to find \"/v1, Resource=pods\" that match label selector \"a=b\", field selector \".spec.nodeName=foo\": pods \"foo\" not found",
expectStatusErr: true,
}, {
name: "non StatusError without selectors",
err: fmt.Errorf("extra info: %w", apierrors.NewNotFound(podGVR.GroupResource(),
"foo")),
opts: metav1.ListOptions{},
subj: podSubject,
expectedErr: "Unable to list \"/v1, Resource=pods\": extra info: pods \"foo\" not found",
expectStatusErr: false,
}, {
name: "non StatusError with selectors",
err: fmt.Errorf("extra info: %w", apierrors.NewNotFound(podGVR.GroupResource(), "foo")),
opts: metav1.ListOptions{
LabelSelector: "a=b",
FieldSelector: ".spec.nodeName=foo",
},
subj: podSubject,
expectedErr: "Unable to find \"/v1, " +
"Resource=pods\" that match label selector \"a=b\", " +
"field selector \".spec.nodeName=foo\": extra info: pods \"foo\" not found",
expectStatusErr: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
err := EnhanceListError(tt.err, tt.opts, tt.subj)
if err == nil {
t.Errorf("EnhanceListError did not return an error")
}
if err.Error() != tt.expectedErr {
t.Errorf("EnhanceListError() error = %q, expectedErr %q", err, tt.expectedErr)
}
if tt.expectStatusErr {
if _, ok := err.(*apierrors.StatusError); !ok {
t.Errorf("EnhanceListError incorrectly returned a non-StatusError: %v", err)
}
}
})
}
}
func TestFollowContinue(t *testing.T) {
var continueTokens []string
tests := []struct {
name string
initialOpts *metav1.ListOptions
tokensSeen []string
listFunc func(metav1.ListOptions) (runtime.Object, error)
expectedTokens []string
wantErr string
}{
{
name: "updates list options with continue token until list finished",
initialOpts: &metav1.ListOptions{},
listFunc: func(options metav1.ListOptions) (runtime.Object, error) {
continueTokens = append(continueTokens, options.Continue)
obj := corev1.PodList{}
switch options.Continue {
case "":
metadataAccessor.SetContinue(&obj, "abc")
case "abc":
metadataAccessor.SetContinue(&obj, "def")
case "def":
metadataAccessor.SetKind(&obj, "ListComplete")
}
return &obj, nil
},
expectedTokens: []string{"", "abc", "def"},
},
{
name: "stops looping if listFunc returns an error",
initialOpts: &metav1.ListOptions{},
listFunc: func(options metav1.ListOptions) (runtime.Object, error) {
continueTokens = append(continueTokens, options.Continue)
obj := corev1.PodList{}
switch options.Continue {
case "":
metadataAccessor.SetContinue(&obj, "abc")
case "abc":
return nil, fmt.Errorf("err from list func")
case "def":
metadataAccessor.SetKind(&obj, "ListComplete")
}
return &obj, nil
},
expectedTokens: []string{"", "abc"},
wantErr: "err from list func",
},
}
for _, tt := range tests {
continueTokens = []string{}
t.Run(tt.name, func(t *testing.T) {
err := FollowContinue(tt.initialOpts, tt.listFunc)
if tt.wantErr != "" {
if err == nil {
t.Fatalf("FollowContinue was expected to return an error and did not")
} else if err.Error() != tt.wantErr {
t.Fatalf("wanted error %q, got %q", tt.wantErr, err.Error())
}
} else {
if err != nil {
t.Errorf("FollowContinue failed: %v", tt.wantErr)
}
if !reflect.DeepEqual(continueTokens, tt.expectedTokens) {
t.Errorf("got token list %q, wanted %q", continueTokens, tt.expectedTokens)
}
}
})
}
}

View File

@ -17,11 +17,9 @@ limitations under the License.
package resource
import (
"fmt"
"k8s.io/apimachinery/pkg/api/errors"
"k8s.io/apimachinery/pkg/api/meta"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/watch"
)
@ -49,41 +47,23 @@ func NewSelector(client RESTClient, mapping *meta.RESTMapping, namespace, labelS
// Visit implements Visitor and uses request chunking by default.
func (r *Selector) Visit(fn VisitorFunc) error {
var continueToken string
for {
list, err := NewHelper(r.Client, r.Mapping).List(
helper := NewHelper(r.Client, r.Mapping)
initialOpts := metav1.ListOptions{
LabelSelector: r.LabelSelector,
FieldSelector: r.FieldSelector,
Limit: r.LimitChunks,
}
return FollowContinue(&initialOpts, func(options metav1.ListOptions) (runtime.Object, error) {
list, err := helper.List(
r.Namespace,
r.ResourceMapping().GroupVersionKind.GroupVersion().String(),
&metav1.ListOptions{
LabelSelector: r.LabelSelector,
FieldSelector: r.FieldSelector,
Limit: r.LimitChunks,
Continue: continueToken,
},
&options,
)
if err != nil {
if errors.IsResourceExpired(err) {
return err
}
if errors.IsBadRequest(err) || errors.IsNotFound(err) {
if se, ok := err.(*errors.StatusError); ok {
// modify the message without hiding this is an API error
if len(r.LabelSelector) == 0 && len(r.FieldSelector) == 0 {
se.ErrStatus.Message = fmt.Sprintf("Unable to list %q: %v", r.Mapping.Resource, se.ErrStatus.Message)
} else {
se.ErrStatus.Message = fmt.Sprintf("Unable to find %q that match label selector %q, field selector %q: %v", r.Mapping.Resource, r.LabelSelector, r.FieldSelector, se.ErrStatus.Message)
}
return se
}
if len(r.LabelSelector) == 0 && len(r.FieldSelector) == 0 {
return fmt.Errorf("Unable to list %q: %v", r.Mapping.Resource, err)
}
return fmt.Errorf("Unable to find %q that match label selector %q, field selector %q: %v", r.Mapping.Resource, r.LabelSelector, r.FieldSelector, err)
}
return err
return nil, EnhanceListError(err, options, r.Mapping.Resource.String())
}
resourceVersion, _ := metadataAccessor.ResourceVersion(list)
nextContinueToken, _ := metadataAccessor.Continue(list)
info := &Info{
Client: r.Client,
Mapping: r.Mapping,
@ -95,13 +75,10 @@ func (r *Selector) Visit(fn VisitorFunc) error {
}
if err := fn(info, nil); err != nil {
return err
return nil, err
}
if len(nextContinueToken) == 0 {
return nil
}
continueToken = nextContinueToken
}
return list, nil
})
}
func (r *Selector) Watch(resourceVersion string) (watch.Interface, error) {