mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-18 19:10:21 +00:00
119 lines
3.7 KiB
Go
119 lines
3.7 KiB
Go
/*
|
|
Copyright 2017 The Kubernetes Authors.
|
|
|
|
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 pager
|
|
|
|
import (
|
|
"fmt"
|
|
|
|
"golang.org/x/net/context"
|
|
|
|
"k8s.io/apimachinery/pkg/api/errors"
|
|
"k8s.io/apimachinery/pkg/api/meta"
|
|
metainternalversion "k8s.io/apimachinery/pkg/apis/meta/internalversion"
|
|
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
|
|
"k8s.io/apimachinery/pkg/runtime"
|
|
)
|
|
|
|
const defaultPageSize = 500
|
|
|
|
// ListPageFunc returns a list object for the given list options.
|
|
type ListPageFunc func(ctx context.Context, opts metav1.ListOptions) (runtime.Object, error)
|
|
|
|
// SimplePageFunc adapts a context-less list function into one that accepts a context.
|
|
func SimplePageFunc(fn func(opts metav1.ListOptions) (runtime.Object, error)) ListPageFunc {
|
|
return func(ctx context.Context, opts metav1.ListOptions) (runtime.Object, error) {
|
|
return fn(opts)
|
|
}
|
|
}
|
|
|
|
// ListPager assists client code in breaking large list queries into multiple
|
|
// smaller chunks of PageSize or smaller. PageFn is expected to accept a
|
|
// metav1.ListOptions that supports paging and return a list. The pager does
|
|
// not alter the field or label selectors on the initial options list.
|
|
type ListPager struct {
|
|
PageSize int64
|
|
PageFn ListPageFunc
|
|
|
|
FullListIfExpired bool
|
|
}
|
|
|
|
// New creates a new pager from the provided pager function using the default
|
|
// options. It will fall back to a full list if an expiration error is encountered
|
|
// as a last resort.
|
|
func New(fn ListPageFunc) *ListPager {
|
|
return &ListPager{
|
|
PageSize: defaultPageSize,
|
|
PageFn: fn,
|
|
FullListIfExpired: true,
|
|
}
|
|
}
|
|
|
|
// TODO: introduce other types of paging functions - such as those that retrieve from a list
|
|
// of namespaces.
|
|
|
|
// List returns a single list object, but attempts to retrieve smaller chunks from the
|
|
// server to reduce the impact on the server. If the chunk attempt fails, it will load
|
|
// the full list instead. The Limit field on options, if unset, will default to the page size.
|
|
func (p *ListPager) List(ctx context.Context, options metav1.ListOptions) (runtime.Object, error) {
|
|
if options.Limit == 0 {
|
|
options.Limit = p.PageSize
|
|
}
|
|
var list *metainternalversion.List
|
|
for {
|
|
obj, err := p.PageFn(ctx, options)
|
|
if err != nil {
|
|
if !errors.IsResourceExpired(err) || !p.FullListIfExpired {
|
|
return nil, err
|
|
}
|
|
// the list expired while we were processing, fall back to a full list
|
|
options.Limit = 0
|
|
options.Continue = ""
|
|
return p.PageFn(ctx, options)
|
|
}
|
|
m, err := meta.ListAccessor(obj)
|
|
if err != nil {
|
|
return nil, fmt.Errorf("returned object must be a list: %v", err)
|
|
}
|
|
|
|
// exit early and return the object we got if we haven't processed any pages
|
|
if len(m.GetContinue()) == 0 && list == nil {
|
|
return obj, nil
|
|
}
|
|
|
|
// initialize the list and fill its contents
|
|
if list == nil {
|
|
list = &metainternalversion.List{Items: make([]runtime.Object, 0, options.Limit+1)}
|
|
list.ResourceVersion = m.GetResourceVersion()
|
|
list.SelfLink = m.GetSelfLink()
|
|
}
|
|
if err := meta.EachListItem(obj, func(obj runtime.Object) error {
|
|
list.Items = append(list.Items, obj)
|
|
return nil
|
|
}); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
// if we have no more items, return the list
|
|
if len(m.GetContinue()) == 0 {
|
|
return list, nil
|
|
}
|
|
|
|
// set the next loop up
|
|
options.Continue = m.GetContinue()
|
|
}
|
|
}
|