README
¶
ctxsignal
Package ctxsignal can be used to create contexts cancelable by system signals.
Example
Creating a context copy cancelable when intercepting a SIGINT, SIGTERM, or SIGHUP signal:
ctx, cancel := ctxsignal.WithSignals(context.Background(), syscall.SIGINT, syscall.SIGTERM, syscall.SIGHUP)
defer cancel()
<-ctx.Done()
fmt.Println("Received signal!")
You can check what type of signal was received with:
sig, err := ctxsignal.Closed(ctx)
if err != nil {
return err
}
fmt.Println(sig) // sig type is os.Signal
You can send a signal using kill -SIGNAL PID. Example: kill -SIGHUP 170.
On Unix-like systems you can read the manual about signals with
$ man signal
Signals available on a typical Linux system
$ kill -l
1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL
5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE
9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2
13) SIGPIPE 14) SIGALRM 15) SIGTERM 16) SIGSTKFLT
17) SIGCHLD 18) SIGCONT 19) SIGSTOP 20) SIGTSTP
21) SIGTTIN 22) SIGTTOU 23) SIGURG 24) SIGXCPU
25) SIGXFSZ 26) SIGVTALRM 27) SIGPROF 28) SIGWINCH
29) SIGPOLL 30) SIGPWR 31) SIGSYS 32) SIGRTMIN
64) SIGRTMAX
SIGKILL and SIGSTOP signals cannot be intercepted or handled.
See the docs for more examples and information.
Documentation
¶
Overview ¶
Package ctxsignal can be used to create contexts cancelable by system signals.
You can send a signal using kill -SIGNAL PID (e.g., kill -SIGHUP 170).
kill -l gives you a list of signals available on your system. On Unix-like systems you can use "man signal" to learn about signals. SIGKILL and SIGSTOP signals cannot be intercepted or handled.
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Closed ¶
Closed gets the signal that closed a context channel.
Example ¶
package main
import (
"context"
"fmt"
"os"
"syscall"
"github.com/henvic/ctxsignal"
)
func main() {
ctx, cancel := ctxsignal.WithSignals(context.Background(), syscall.SIGHUP)
defer cancel()
// Remove this Go routine to test manually with kill -HUP PID.
go func() {
p, _ := os.FindProcess(os.Getpid()) // always check your errors!
_ = p.Signal(syscall.SIGHUP) // don't ignore errors!
}()
<-ctx.Done()
sig, err := ctxsignal.Closed(ctx)
if err != nil {
_, _ = fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
fmt.Println(sig)
}
Output: hangup
func WithSignals ¶
func WithSignals(parent context.Context, signals ...os.Signal) (context.Context, context.CancelFunc)
WithSignals returns a copy of the parent context cancelable by the given system signals. The signals are reset when the context's Done channel is closed.
Example ¶
package main
import (
"context"
"fmt"
"os"
"syscall"
"github.com/henvic/ctxsignal"
)
func main() {
ctx, cancel := ctxsignal.WithSignals(context.Background(), syscall.SIGUSR2)
defer cancel()
// Remove this Go routine to test manually with kill -USR2 PID.
go func() {
p, _ := os.FindProcess(os.Getpid()) // always check your errors!
_ = p.Signal(syscall.SIGUSR2) // don't ignore errors!
}()
<-ctx.Done()
fmt.Println("Signaled!")
}
Output: Signaled!
func WithTermination ¶
WithTermination creates a context canceled on signals SIGINT or SIGTERM.
Example ¶
package main
import (
"context"
"fmt"
"os"
"syscall"
"github.com/henvic/ctxsignal"
)
func main() {
ctx, cancel := ctxsignal.WithTermination(context.Background())
defer cancel()
// Remove this Go routine to test manually.
go func() {
p, _ := os.FindProcess(os.Getpid()) // always check your errors!
_ = p.Signal(syscall.SIGINT) // don't ignore errors!
}()
<-ctx.Done()
fmt.Println("Interrupted!")
}
Output: Interrupted!
Types ¶
This section is empty.
Notes ¶
Bugs ¶
Be aware signal handling is vulnerable to race conditions.
Source Files
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- ctxsignal.go