From 56e3ab094386e80384ce8d1b71a69bf87bf5c2ea Mon Sep 17 00:00:00 2001
From: Gyu-Ho Lee <gyuhox@gmail.com>
Date: Tue, 16 Feb 2016 11:03:12 -0800
Subject: [PATCH] etcd-agent: tidy cleanup before SIGKILL

https://github.com/golang/go/blob/master/src/os/exec_posix.go#L18 shows that
cmd.Process.Kill calls syscall.SIGKILL to the command. But
http://tldp.org/LDP/Bash-Beginners-Guide/html/sect_12_01.html explains
'If you send a SIGKILL to a process, you remove any chance for the process to
do a tidy cleanup and shutdown, which might have unfortunate consequences.'
This sends SIGTERM, SIGINT syscalls to the PID so that the process could
have more time to clean up the resources.

Related to https://github.com/coreos/etcd/issues/4517.
---
 tools/functional-tester/etcd-agent/agent.go | 34 ++++++++++++++++-----
 1 file changed, 27 insertions(+), 7 deletions(-)

diff --git a/tools/functional-tester/etcd-agent/agent.go b/tools/functional-tester/etcd-agent/agent.go
index b0b701031..a1e724dd4 100644
--- a/tools/functional-tester/etcd-agent/agent.go
+++ b/tools/functional-tester/etcd-agent/agent.go
@@ -21,6 +21,7 @@ import (
 	"os"
 	"os/exec"
 	"path"
+	"syscall"
 	"time"
 
 	"github.com/coreos/etcd/pkg/netutil"
@@ -80,20 +81,39 @@ func (a *Agent) stop() error {
 	if a.state != stateStarted {
 		return nil
 	}
-	err := a.cmd.Process.Kill()
-	if err != nil {
-		return err
-	}
-	_, err = a.cmd.Process.Wait()
-	if err != nil {
-		return err
 
+	err := sigtermAndWait(a.cmd)
+	if err != nil {
+		return err
 	}
 
 	a.state = stateStopped
 	return nil
 }
 
+func sigtermAndWait(cmd *exec.Cmd) error {
+	err := cmd.Process.Signal(syscall.SIGTERM)
+	if err != nil {
+		return err
+	}
+
+	errc := make(chan error)
+	go func() {
+		_, err := cmd.Process.Wait()
+		errc <- err
+		close(errc)
+	}()
+
+	select {
+	case <-time.After(5 * time.Second):
+		cmd.Process.Kill()
+	case err := <-errc:
+		return err
+	}
+	err = <-errc
+	return err
+}
+
 // restart restarts the stopped etcd process.
 func (a *Agent) restart() error {
 	a.cmd = exec.Command(a.cmd.Path, a.cmd.Args[1:]...)