mirror of
https://github.com/ceph/ceph-csi.git
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5af3fe5deb
this commits add the controller runtime and its dependency to the vendor. Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>
324 lines
9.4 KiB
Go
324 lines
9.4 KiB
Go
/*
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Copyright 2019 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package apiutil
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import (
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"errors"
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"sync"
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"time"
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"golang.org/x/time/rate"
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"k8s.io/apimachinery/pkg/api/meta"
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"k8s.io/apimachinery/pkg/runtime/schema"
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"k8s.io/client-go/discovery"
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"k8s.io/client-go/rest"
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"k8s.io/client-go/restmapper"
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)
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// ErrRateLimited is returned by a RESTMapper method if the number of API
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// calls has exceeded a limit within a certain time period.
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type ErrRateLimited struct {
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// Duration to wait until the next API call can be made.
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Delay time.Duration
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}
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func (e ErrRateLimited) Error() string {
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return "too many API calls to the RESTMapper within a timeframe"
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}
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// DelayIfRateLimited returns the delay time until the next API call is
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// allowed and true if err is of type ErrRateLimited. The zero
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// time.Duration value and false are returned if err is not a ErrRateLimited.
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func DelayIfRateLimited(err error) (time.Duration, bool) {
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var rlerr ErrRateLimited
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if errors.As(err, &rlerr) {
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return rlerr.Delay, true
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}
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return 0, false
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}
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// dynamicRESTMapper is a RESTMapper that dynamically discovers resource
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// types at runtime.
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type dynamicRESTMapper struct {
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mu sync.RWMutex // protects the following fields
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staticMapper meta.RESTMapper
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limiter *dynamicLimiter
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newMapper func() (meta.RESTMapper, error)
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lazy bool
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// Used for lazy init.
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initOnce sync.Once
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}
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// DynamicRESTMapperOption is a functional option on the dynamicRESTMapper
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type DynamicRESTMapperOption func(*dynamicRESTMapper) error
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// WithLimiter sets the RESTMapper's underlying limiter to lim.
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func WithLimiter(lim *rate.Limiter) DynamicRESTMapperOption {
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return func(drm *dynamicRESTMapper) error {
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drm.limiter = &dynamicLimiter{lim}
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return nil
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}
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}
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// WithLazyDiscovery prevents the RESTMapper from discovering REST mappings
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// until an API call is made.
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var WithLazyDiscovery DynamicRESTMapperOption = func(drm *dynamicRESTMapper) error {
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drm.lazy = true
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return nil
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}
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// WithCustomMapper supports setting a custom RESTMapper refresher instead of
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// the default method, which uses a discovery client.
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//
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// This exists mainly for testing, but can be useful if you need tighter control
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// over how discovery is performed, which discovery endpoints are queried, etc.
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func WithCustomMapper(newMapper func() (meta.RESTMapper, error)) DynamicRESTMapperOption {
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return func(drm *dynamicRESTMapper) error {
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drm.newMapper = newMapper
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return nil
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}
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}
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// NewDynamicRESTMapper returns a dynamic RESTMapper for cfg. The dynamic
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// RESTMapper dynamically discovers resource types at runtime. opts
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// configure the RESTMapper.
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func NewDynamicRESTMapper(cfg *rest.Config, opts ...DynamicRESTMapperOption) (meta.RESTMapper, error) {
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client, err := discovery.NewDiscoveryClientForConfig(cfg)
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if err != nil {
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return nil, err
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}
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drm := &dynamicRESTMapper{
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limiter: &dynamicLimiter{
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rate.NewLimiter(rate.Limit(defaultRefillRate), defaultLimitSize),
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},
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newMapper: func() (meta.RESTMapper, error) {
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groupResources, err := restmapper.GetAPIGroupResources(client)
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if err != nil {
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return nil, err
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}
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return restmapper.NewDiscoveryRESTMapper(groupResources), nil
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},
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}
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for _, opt := range opts {
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if err = opt(drm); err != nil {
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return nil, err
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}
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}
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if !drm.lazy {
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if err := drm.setStaticMapper(); err != nil {
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return nil, err
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}
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}
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return drm, nil
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}
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var (
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// defaultRefilRate is the default rate at which potential calls are
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// added back to the "bucket" of allowed calls.
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defaultRefillRate = 5
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// defaultLimitSize is the default starting/max number of potential calls
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// per second. Once a call is used, it's added back to the bucket at a rate
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// of defaultRefillRate per second.
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defaultLimitSize = 5
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)
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// setStaticMapper sets drm's staticMapper by querying its client, regardless
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// of reload backoff.
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func (drm *dynamicRESTMapper) setStaticMapper() error {
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newMapper, err := drm.newMapper()
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if err != nil {
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return err
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}
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drm.staticMapper = newMapper
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return nil
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}
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// init initializes drm only once if drm is lazy.
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func (drm *dynamicRESTMapper) init() (err error) {
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drm.initOnce.Do(func() {
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if drm.lazy {
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err = drm.setStaticMapper()
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}
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})
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return err
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}
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// checkAndReload attempts to call the given callback, which is assumed to be dependent
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// on the data in the restmapper.
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//
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// If the callback returns a NoKindMatchError, it will attempt to reload
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// the RESTMapper's data and re-call the callback once that's occurred.
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// If the callback returns any other error, the function will return immediately regardless.
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//
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// It will take care
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// ensuring that reloads are rate-limitted and that extraneous calls aren't made.
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// It's thread-safe, and worries about thread-safety for the callback (so the callback does
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// not need to attempt to lock the restmapper).
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func (drm *dynamicRESTMapper) checkAndReload(needsReloadErr error, checkNeedsReload func() error) error {
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// first, check the common path -- data is fresh enough
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// (use an IIFE for the lock's defer)
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err := func() error {
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drm.mu.RLock()
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defer drm.mu.RUnlock()
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return checkNeedsReload()
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}()
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// NB(directxman12): `Is` and `As` have a confusing relationship --
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// `Is` is like `== or does this implement .Is`, whereas `As` says
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// `can I type-assert into`
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needsReload := errors.As(err, &needsReloadErr)
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if !needsReload {
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return err
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}
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// if the data wasn't fresh, we'll need to try and update it, so grab the lock...
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drm.mu.Lock()
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defer drm.mu.Unlock()
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// ... and double-check that we didn't reload in the meantime
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err = checkNeedsReload()
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needsReload = errors.As(err, &needsReloadErr)
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if !needsReload {
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return err
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}
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// we're still stale, so grab a rate-limit token if we can...
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if err := drm.limiter.checkRate(); err != nil {
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return err
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}
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// ...reload...
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if err := drm.setStaticMapper(); err != nil {
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return err
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}
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// ...and return the results of the closure regardless
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return checkNeedsReload()
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}
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// TODO: wrap reload errors on NoKindMatchError with go 1.13 errors.
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func (drm *dynamicRESTMapper) KindFor(resource schema.GroupVersionResource) (schema.GroupVersionKind, error) {
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if err := drm.init(); err != nil {
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return schema.GroupVersionKind{}, err
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}
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var gvk schema.GroupVersionKind
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err := drm.checkAndReload(&meta.NoResourceMatchError{}, func() error {
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var err error
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gvk, err = drm.staticMapper.KindFor(resource)
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return err
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})
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return gvk, err
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}
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func (drm *dynamicRESTMapper) KindsFor(resource schema.GroupVersionResource) ([]schema.GroupVersionKind, error) {
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if err := drm.init(); err != nil {
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return nil, err
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}
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var gvks []schema.GroupVersionKind
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err := drm.checkAndReload(&meta.NoResourceMatchError{}, func() error {
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var err error
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gvks, err = drm.staticMapper.KindsFor(resource)
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return err
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})
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return gvks, err
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}
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func (drm *dynamicRESTMapper) ResourceFor(input schema.GroupVersionResource) (schema.GroupVersionResource, error) {
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if err := drm.init(); err != nil {
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return schema.GroupVersionResource{}, err
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}
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var gvr schema.GroupVersionResource
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err := drm.checkAndReload(&meta.NoResourceMatchError{}, func() error {
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var err error
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gvr, err = drm.staticMapper.ResourceFor(input)
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return err
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})
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return gvr, err
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}
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func (drm *dynamicRESTMapper) ResourcesFor(input schema.GroupVersionResource) ([]schema.GroupVersionResource, error) {
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if err := drm.init(); err != nil {
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return nil, err
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}
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var gvrs []schema.GroupVersionResource
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err := drm.checkAndReload(&meta.NoResourceMatchError{}, func() error {
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var err error
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gvrs, err = drm.staticMapper.ResourcesFor(input)
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return err
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})
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return gvrs, err
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}
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func (drm *dynamicRESTMapper) RESTMapping(gk schema.GroupKind, versions ...string) (*meta.RESTMapping, error) {
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if err := drm.init(); err != nil {
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return nil, err
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}
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var mapping *meta.RESTMapping
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err := drm.checkAndReload(&meta.NoKindMatchError{}, func() error {
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var err error
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mapping, err = drm.staticMapper.RESTMapping(gk, versions...)
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return err
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})
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return mapping, err
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}
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func (drm *dynamicRESTMapper) RESTMappings(gk schema.GroupKind, versions ...string) ([]*meta.RESTMapping, error) {
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if err := drm.init(); err != nil {
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return nil, err
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}
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var mappings []*meta.RESTMapping
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err := drm.checkAndReload(&meta.NoKindMatchError{}, func() error {
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var err error
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mappings, err = drm.staticMapper.RESTMappings(gk, versions...)
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return err
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})
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return mappings, err
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}
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func (drm *dynamicRESTMapper) ResourceSingularizer(resource string) (string, error) {
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if err := drm.init(); err != nil {
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return "", err
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}
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var singular string
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err := drm.checkAndReload(&meta.NoResourceMatchError{}, func() error {
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var err error
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singular, err = drm.staticMapper.ResourceSingularizer(resource)
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return err
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})
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return singular, err
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}
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// dynamicLimiter holds a rate limiter used to throttle chatty RESTMapper users.
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type dynamicLimiter struct {
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*rate.Limiter
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}
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// checkRate returns an ErrRateLimited if too many API calls have been made
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// within the set limit.
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func (b *dynamicLimiter) checkRate() error {
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res := b.Reserve()
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if res.Delay() == 0 {
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return nil
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}
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res.Cancel()
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return ErrRateLimited{res.Delay()}
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}
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