Use chan only to notify command is done

pkg/app/launcher/cmd/launcher/binary.go

@@ -21,6 +21,7 @@
  "os"
  "os/exec"
  "path/filepath"
+ "sync/atomic"
  "syscall"
  "time"
 
@@ -29,7 +30,8 @@
 
 type command struct {
  cmd *exec.Cmd
- stoppedCh chan error
+ stoppedCh chan struct{}
+ result atomic.Pointer[error]
 }
 
 func (c *command) IsRunning() bool {
@@ -50,9 +52,16 @@
  select {
  case <-timer.C:
  c.cmd.Process.Kill()
- return <-c.stoppedCh
- case err := <-c.stoppedCh:
- return err
+ <-c.stoppedCh
+ if perr := c.result.Load(); perr != nil {
+ return *perr
+ }
+ return nil
+ case <-c.stoppedCh:
+ if perr := c.result.Load(); perr != nil {
+ return *perr
+ }
+ return nil
  }
 }
 
@@ -68,11 +77,12 @@
 
  c := &command{
  cmd: cmd,
- stoppedCh: make(chan error, 1),
+ stoppedCh: make(chan struct{}),
+ result: atomic.Pointer[error]{},
  }
  go func() {
  err := cmd.Wait()
- c.stoppedCh <- err
+ c.result.Store(&err)
  close(c.stoppedCh)
  }()
 

pkg/app/launcher/cmd/launcher/binary_test.go

@@ -15,6 +15,7 @@
 package launcher
 
 import (
+ "strconv"
  "testing"
  "time"
 
@@ -49,3 +50,34 @@ func TestGracefulStopCommand(t *testing.T) {
  })
  }
 }
+
+func TestGracefulStopCommandResult(t *testing.T) {
+ testcases := []struct {
+ name string
+ exitCode int
+ assertion assert.ErrorAssertionFunc
+ }{
+ {
+ name: "successfully exit",
+ exitCode: 0,
+ assertion: assert.NoError,
+ },
+ {
+ name: "exit with an error",
+ exitCode: 1,
+ assertion: assert.Error,
+ },
+ }
+
+ for _, tc := range testcases {
+ t.Run(tc.name, func(t *testing.T) {
+ cmd, err := runBinary("sh", []string{"-c", "exit " + strconv.Itoa(tc.exitCode)})
+ require.NoError(t, err)
+ require.NotNil(t, cmd)
+
+ time.Sleep(100 * time.Millisecond) // to avoid GracefulStop executed before the command exits
+ tc.assertion(t, cmd.GracefulStop(time.Second))
+ assert.False(t, cmd.IsRunning())
+ })
+ }
+}