Added a test which shows userpid is killed when plugin can not be re-connected on calling Open

client/driver/exec_test.go

@@ -1,8 +1,10 @@
 package driver
 
 import (
+	"encoding/json"
 	"fmt"
 	"io/ioutil"
+	"os"
 	"path/filepath"
 	"reflect"
 	"testing"
@@ -75,6 +77,56 @@ func TestExecDriver_StartOpen_Wait(t *testing.T) {
 	handle2.Kill()
 }
 
+func TestExecDriver_KillUserPid_OnPluginReconnectFailure(t *testing.T) {
+	t.Parallel()
+	ctestutils.ExecCompatible(t)
+	task := &structs.Task{
+		Name: "sleep",
+		Config: map[string]interface{}{
+			"command": "/bin/sleep",
+			"args":    []string{"1000000"},
+		},
+		Resources: basicResources,
+	}
+
+	driverCtx, execCtx := testDriverContexts(task)
+	defer execCtx.AllocDir.Destroy()
+	d := NewExecDriver(driverCtx)
+
+	handle, err := d.Start(execCtx, task)
+	defer handle.Kill()
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+	if handle == nil {
+		t.Fatalf("missing handle")
+	}
+
+	id := &execId{}
+	if err := json.Unmarshal([]byte(handle.ID()), id); err != nil {
+		t.Fatalf("Failed to parse handle '%s': %v", handle.ID(), err)
+	}
+	pluginPid := id.PluginConfig.Pid
+	proc, err := os.FindProcess(pluginPid)
+	if err != nil {
+		t.Fatalf("can't find plugin pid: %v", pluginPid)
+	}
+	if err := proc.Kill(); err != nil {
+		t.Fatalf("can't kill plugin pid: %v", err)
+	}
+
+	// Attempt to open
+	handle2, err := d.Open(execCtx, handle.ID())
+	userProc, err := os.FindProcess(id.UserPid)
+	if err := userProc.Kill(); err == nil {
+		t.Fatalf("user process is supposed to be killed when plugin exits")
+	}
+	if handle2 != nil {
+		defer handle2.Kill()
+		t.Fatalf("expected handle2 to be nil")
+	}
+}
+
 func TestExecDriver_Start_Wait(t *testing.T) {
 	t.Parallel()
 	ctestutils.ExecCompatible(t)