allow controlling the stop signal in exec/raw_exec

CHANGELOG.md

@@ -30,6 +30,7 @@ IMPROVEMENTS:
  * driver/docker: Adds support for `ulimit` and `sysctl` options [GH-3568]
  * driver/docker: Adds support for StopTimeout (set to the same value as
    kill_timeout [GH-3601]
+ * driver/exec:  allow controlling the stop signal in exec/raw_exec [GH-1755]
  * driver/rkt: Add support for passing through user [GH-3612]
  * driver/qemu: Support graceful shutdowns on unix platforms [GH-3411]
  * template: Updated to consul template 0.19.4 [GH-3543]

client/driver/exec.go

@@ -31,8 +31,9 @@ type ExecDriver struct {
 }
 
 type ExecDriverConfig struct {
-	Command string   `mapstructure:"command"`
-	Args    []string `mapstructure:"args"`
+	Command    string   `mapstructure:"command"`
+	Args       []string `mapstructure:"args"`
+	KillSignal string   `mapstructure:"kill_signal"`
 }
 
 // execHandle is returned from Start/Open as a handle to the PID
@@ -67,6 +68,9 @@ func (d *ExecDriver) Validate(config map[string]interface{}) error {
 			"args": {
 				Type: fields.TypeArray,
 			},
+			"kill_signal": {
+				Type: fields.TypeString,
+			},
 		},
 	}
 
@@ -132,6 +136,7 @@ func (d *ExecDriver) Start(ctx *ExecContext, task *structs.Task) (*StartResponse
 	execCmd := &executor.ExecCommand{
 		Cmd:            command,
 		Args:           driverConfig.Args,
+		KillSignal:     driverConfig.KillSignal,
 		FSIsolation:    true,
 		ResourceLimits: true,
 		User:           getExecutorUser(task),

client/driver/executor/executor.go

@@ -98,6 +98,8 @@ type ExecCommand struct {
 	// Args is the args of the command that the user wants to run.
 	Args []string
 
+	KillSignal string
+
 	// FSIsolation determines whether the command would be run in a chroot.
 	FSIsolation bool
 
@@ -481,6 +483,21 @@ func (e *UniversalExecutor) Exit() error {
 	return merr.ErrorOrNil()
 }
 
+// Look to see if the user has specified a kill command. If non has been
+// specified, default to SIGQUIT.
+func getMatchingSyscall(sys string) syscall.Signal {
+	switch sys {
+	case "SIGINT":
+		return syscall.SIGINT
+	case "SIGUSR1":
+		return syscall.SIGUSR1
+	case "SIGUSR2":
+		return syscall.SIGUSR2
+	default:
+		return syscall.SIGQUIT
+	}
+}
+
 // Shutdown sends an interrupt signal to the user process
 func (e *UniversalExecutor) ShutDown() error {
 	if e.cmd.Process == nil {
@@ -496,9 +513,18 @@ func (e *UniversalExecutor) ShutDown() error {
 		}
 		return nil
 	}
-	if err = proc.Signal(os.Interrupt); err != nil && err.Error() != finishedErr {
+
+	var killErr error
+	if e.command.KillSignal != "" {
+		sys := getMatchingSyscall(e.command.KillSignal)
+		killErr = syscall.Kill(e.cmd.Process.Pid, sys)
+	} else {
+		killErr = proc.Signal(os.Interrupt)
+	}
+	if killErr != nil && killErr.Error() != finishedErr {
 		return fmt.Errorf("executor.shutdown error: %v", err)
 	}
+
 	return nil
 }