First commit

core/setup/startupshutdown.go

@@ -0,0 +1,64 @@
+package setup
+
+import (
+	"os"
+	"os/exec"
+	"strings"
+
+	"github.com/miekg/coredns/middleware"
+)
+
+// Startup registers a startup callback to execute during server start.
+func Startup(c *Controller) (middleware.Middleware, error) {
+	return nil, registerCallback(c, &c.FirstStartup)
+}
+
+// Shutdown registers a shutdown callback to execute during process exit.
+func Shutdown(c *Controller) (middleware.Middleware, error) {
+	return nil, registerCallback(c, &c.Shutdown)
+}
+
+// registerCallback registers a callback function to execute by
+// using c to parse the line. It appends the callback function
+// to the list of callback functions passed in by reference.
+func registerCallback(c *Controller, list *[]func() error) error {
+	var funcs []func() error
+
+	for c.Next() {
+		args := c.RemainingArgs()
+		if len(args) == 0 {
+			return c.ArgErr()
+		}
+
+		nonblock := false
+		if len(args) > 1 && args[len(args)-1] == "&" {
+			// Run command in background; non-blocking
+			nonblock = true
+			args = args[:len(args)-1]
+		}
+
+		command, args, err := middleware.SplitCommandAndArgs(strings.Join(args, " "))
+		if err != nil {
+			return c.Err(err.Error())
+		}
+
+		fn := func() error {
+			cmd := exec.Command(command, args...)
+			cmd.Stdin = os.Stdin
+			cmd.Stdout = os.Stdout
+			cmd.Stderr = os.Stderr
+
+			if nonblock {
+				return cmd.Start()
+			}
+			return cmd.Run()
+		}
+
+		funcs = append(funcs, fn)
+	}
+
+	return c.OncePerServerBlock(func() error {
+		*list = append(*list, funcs...)
+		return nil
+	})
+}