1 /* 2 Copyright 2017 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 signals 18 19 import ( 20 "context" 21 "os" 22 "os/signal" 23 ) 24 25 var onlyOneSignalHandler = make(chan struct{}) 26 27 // SetupSignalHandler registers for SIGTERM and SIGINT. A context is returned 28 // which is canceled on one of these signals. If a second signal is caught, the program 29 // is terminated with exit code 1. 30 func SetupSignalHandler() context.Context { 31 close(onlyOneSignalHandler) // panics when called twice 32 33 ctx, cancel := context.WithCancel(context.Background()) 34 35 c := make(chan os.Signal, 2) 36 signal.Notify(c, shutdownSignals...) 37 go func() { 38 <-c 39 cancel() 40 <-c 41 os.Exit(1) // second signal. Exit directly. 42 }() 43 44 return ctx 45 } 46