1package interrupt
 2
 3import (
 4	"fmt"
 5	"os"
 6	"os/signal"
 7	"syscall"
 8)
 9
10// Cleaner type refers to a function with no inputs that returns an error
11type Cleaner func() error
12
13var cleaners []Cleaner
14var active = false
15
16// RegisterCleaner is responsible for registering a cleaner function. When a function is registered, the Signal watcher is started in a goroutine.
17func RegisterCleaner(f ...Cleaner) {
18	for _, fn := range f {
19		cleaners = append([]Cleaner{fn}, cleaners...)
20		if !active {
21			active = true
22			go func() {
23				ch := make(chan os.Signal, 1)
24				signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM, os.Interrupt)
25				<-ch
26				// Prevent un-terminated ^C character in terminal
27				fmt.Println()
28				errl := clean()
29				for _, err := range errl {
30					fmt.Println(err)
31				}
32				os.Exit(1)
33			}()
34		}
35	}
36}
37
38// clean invokes all registered cleanup functions, and returns a list of errors, if they exist.
39func clean() (errorlist []error) {
40	for _, f := range cleaners {
41		err := f()
42		if err != nil {
43			errorlist = append(errorlist, err)
44		}
45	}
46	cleaners = []Cleaner{}
47	return
48}