go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/system/signals/interrupt.go (about)

     1  // Copyright 2019 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  // Package signals makes it easier to catch SIGTERM.
    16  package signals
    17  
    18  import (
    19  	"fmt"
    20  	"os"
    21  	"os/signal"
    22  )
    23  
    24  // HandleInterrupt calls 'fn' in a separate goroutine on SIGTERM or Ctrl+C.
    25  //
    26  // When SIGTERM or Ctrl+C comes for a second time, logs to stderr and kills
    27  // the process immediately via os.Exit(1).
    28  //
    29  // Returns a callback that can be used to remove the installed signal handlers.
    30  func HandleInterrupt(fn func()) (stopper func()) {
    31  	ch := make(chan os.Signal, 2)
    32  	signal.Notify(ch, Interrupts()...)
    33  
    34  	go func() {
    35  		handled := false
    36  		for range ch {
    37  			if handled {
    38  				fmt.Fprintf(os.Stderr, "Got second interrupt signal. Aborting.\n")
    39  				os.Exit(1)
    40  			}
    41  			handled = true
    42  			go fn()
    43  		}
    44  	}()
    45  
    46  	return func() {
    47  		signal.Stop(ch)
    48  		close(ch)
    49  	}
    50  }