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|
package interrupt
import (
"fmt"
"os"
"os/signal"
"sync"
"syscall"
)
// CleanerFunc is a function to be executed when an interrupt trigger
type CleanerFunc func() error
// CancelFunc, if called, will disable the associated cleaner.
// This allow to create temporary cleaner. Be mindful though to not
// create too much of them as they are just disabled, not removed from
// memory.
type CancelFunc func()
type wrapper struct {
f CleanerFunc
disabled bool
}
var mu sync.Mutex
var cleaners []*wrapper
var handlerCreated = false
// RegisterCleaner is responsible for registering a cleaner function.
// When a function is registered, the Signal watcher is started in a goroutine.
func RegisterCleaner(cleaner CleanerFunc) CancelFunc {
mu.Lock()
defer mu.Unlock()
w := &wrapper{f: cleaner}
cancel := func() {
mu.Lock()
defer mu.Unlock()
w.disabled = true
}
// prepend to later execute then in reverse order
cleaners = append([]*wrapper{w}, cleaners...)
if handlerCreated {
return cancel
}
handlerCreated = true
go func() {
ch := make(chan os.Signal, 1)
signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
<-ch
// Prevent un-terminated ^C character in terminal
fmt.Println()
errl := clean()
for _, err := range errl {
_, _ = fmt.Fprintln(os.Stderr, err)
}
os.Exit(1)
}()
return cancel
}
// clean invokes all registered cleanup functions, and returns a list of errors, if they exist.
func clean() (errorList []error) {
mu.Lock()
defer mu.Unlock()
for _, cleaner := range cleaners {
if cleaner.disabled {
continue
}
err := cleaner.f()
if err != nil {
errorList = append(errorList, err)
}
}
cleaners = []*wrapper{}
return
}
|
