mirror of https://github.com/k3s-io/k3s
146 lines
3.9 KiB
Go
146 lines
3.9 KiB
Go
/*
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Copyright 2017 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 eventratelimit
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import (
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"fmt"
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"strings"
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"github.com/hashicorp/golang-lru"
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apierrors "k8s.io/apimachinery/pkg/api/errors"
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"k8s.io/apiserver/pkg/admission"
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"k8s.io/client-go/util/flowcontrol"
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api "k8s.io/kubernetes/pkg/apis/core"
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eventratelimitapi "k8s.io/kubernetes/plugin/pkg/admission/eventratelimit/apis/eventratelimit"
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)
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const (
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// cache size to use if the user did not specify a cache size
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defaultCacheSize = 4096
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)
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// limitEnforcer enforces a single type of event rate limit, such as server, namespace, or source+object
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type limitEnforcer struct {
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// type of this limit
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limitType eventratelimitapi.LimitType
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// cache for holding the rate limiters
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cache cache
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// a keyFunc which is responsible for computing a single key based on input
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keyFunc func(admission.Attributes) string
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}
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func newLimitEnforcer(config eventratelimitapi.Limit, clock flowcontrol.Clock) (*limitEnforcer, error) {
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rateLimiterFactory := func() flowcontrol.RateLimiter {
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return flowcontrol.NewTokenBucketRateLimiterWithClock(float32(config.QPS), int(config.Burst), clock)
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}
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if config.Type == eventratelimitapi.ServerLimitType {
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return &limitEnforcer{
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limitType: config.Type,
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cache: &singleCache{
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rateLimiter: rateLimiterFactory(),
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},
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keyFunc: getServerKey,
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}, nil
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}
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cacheSize := int(config.CacheSize)
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if cacheSize == 0 {
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cacheSize = defaultCacheSize
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}
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underlyingCache, err := lru.New(cacheSize)
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if err != nil {
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return nil, fmt.Errorf("could not create lru cache: %v", err)
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}
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cache := &lruCache{
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rateLimiterFactory: rateLimiterFactory,
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cache: underlyingCache,
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}
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var keyFunc func(admission.Attributes) string
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switch t := config.Type; t {
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case eventratelimitapi.NamespaceLimitType:
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keyFunc = getNamespaceKey
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case eventratelimitapi.UserLimitType:
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keyFunc = getUserKey
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case eventratelimitapi.SourceAndObjectLimitType:
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keyFunc = getSourceAndObjectKey
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default:
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return nil, fmt.Errorf("unknown event rate limit type: %v", t)
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}
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return &limitEnforcer{
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limitType: config.Type,
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cache: cache,
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keyFunc: keyFunc,
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}, nil
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}
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func (enforcer *limitEnforcer) accept(attr admission.Attributes) error {
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key := enforcer.keyFunc(attr)
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rateLimiter := enforcer.cache.get(key)
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// ensure we have available rate
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allow := rateLimiter.TryAccept()
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if !allow {
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return apierrors.NewTooManyRequestsError(fmt.Sprintf("limit reached on type %v for key %v", enforcer.limitType, key))
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}
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return nil
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}
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func getServerKey(attr admission.Attributes) string {
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return ""
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}
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// getNamespaceKey returns a cache key that is based on the namespace of the event request
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func getNamespaceKey(attr admission.Attributes) string {
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return attr.GetNamespace()
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}
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// getUserKey returns a cache key that is based on the user of the event request
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func getUserKey(attr admission.Attributes) string {
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userInfo := attr.GetUserInfo()
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if userInfo == nil {
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return ""
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}
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return userInfo.GetName()
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}
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// getSourceAndObjectKey returns a cache key that is based on the source+object of the event
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func getSourceAndObjectKey(attr admission.Attributes) string {
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object := attr.GetObject()
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if object == nil {
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return ""
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}
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event, ok := object.(*api.Event)
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if !ok {
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return ""
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}
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return strings.Join([]string{
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event.Source.Component,
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event.Source.Host,
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event.InvolvedObject.Kind,
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event.InvolvedObject.Namespace,
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event.InvolvedObject.Name,
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string(event.InvolvedObject.UID),
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event.InvolvedObject.APIVersion,
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}, "")
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}
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