k8s.io/apiserver@v0.31.1/pkg/server/filters/watch_termination.go (about) 1 /* 2 Copyright 2023 The Kubernetes Authors. 3 4 Licensed under the Apache License, Version 2.0 (the "License"); 5 you may not use this file except in compliance with the License. 6 You may obtain a copy of the License at 7 8 http://www.apache.org/licenses/LICENSE-2.0 9 10 Unless required by applicable law or agreed to in writing, software 11 distributed under the License is distributed on an "AS IS" BASIS, 12 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 See the License for the specific language governing permissions and 14 limitations under the License. 15 */ 16 17 package filters 18 19 import ( 20 "errors" 21 "net/http" 22 23 "k8s.io/apiserver/pkg/endpoints/handlers/responsewriters" 24 apirequest "k8s.io/apiserver/pkg/endpoints/request" 25 "k8s.io/klog/v2" 26 ) 27 28 func WithWatchTerminationDuringShutdown(handler http.Handler, termination apirequest.ServerShutdownSignal, wg RequestWaitGroup) http.Handler { 29 if termination == nil || wg == nil { 30 klog.Warningf("watch termination during shutdown not attached to the handler chain") 31 return handler 32 } 33 return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) { 34 ctx := req.Context() 35 requestInfo, ok := apirequest.RequestInfoFrom(ctx) 36 if !ok { 37 // if this happens, the handler chain isn't setup correctly because there is no request info 38 responsewriters.InternalError(w, req, errors.New("no RequestInfo found in the context")) 39 return 40 } 41 if !watchVerbs.Has(requestInfo.Verb) { 42 handler.ServeHTTP(w, req) 43 return 44 } 45 46 if err := wg.Add(1); err != nil { 47 // When apiserver is shutting down, signal clients to retry 48 // There is a good chance the client hit a different server, so a tight retry is good for client responsiveness. 49 waitGroupWriteRetryAfterToResponse(w) 50 return 51 } 52 53 // attach ServerShutdownSignal to the watch request so that the 54 // watch handler loop can return as soon as the server signals 55 // that it is shutting down. 56 ctx = apirequest.WithServerShutdownSignal(req.Context(), termination) 57 req = req.WithContext(ctx) 58 59 defer wg.Done() 60 handler.ServeHTTP(w, req) 61 }) 62 }