Cancel context on os.Interrupt (#169)

This fixes #117 by
cancelling the global context when Ctrl-C is hit.

The cancelation propagates down to `runAction` where containers that are
still running are killed.

Author: mrnugget

cmd/src/actions_exec.go

@@ -10,6 +10,7 @@ import (
 	"io/ioutil"
 	"os"
 	"os/exec"
+	"os/signal"
 	"path/filepath"
 	"regexp"
 	"runtime"
@@ -183,7 +184,20 @@ Format of the action JSON files:
 			return errors.Wrap(err, "invalid JSON action file")
 		}
 
-		ctx := context.Background()
+		ctx, cancel := context.WithCancel(context.Background())
+		c := make(chan os.Signal, 1)
+		signal.Notify(c, os.Interrupt)
+		defer func() {
+			signal.Stop(c)
+			cancel()
+		}()
+		go func() {
+			select {
+			case <-c:
+				cancel()
+			case <-ctx.Done():
+			}
+		}()
 
 		logger := newActionLogger(*verbose, *keepLogsFlag)