Cancel Context, when exec.Command{} process fails

cancel-context-when-process-fails.go

type ReadCloserWithCancellationWhenProcessFails struct {
    Parent  io.ReadCloser
    Process *exec.Cmd
    Cancel  func()
}

func (r ReadCloserWithCancellationWhenProcessFails) Read(p []byte) (n int, err error) {
    return r.Parent.Read(p)
}

func (r ReadCloserWithCancellationWhenProcessFails) Close() error {
    err := r.Process.Wait()
    exitCode := 0
    if err != nil {
        // try to get the exit code
        if exitError, ok := err.(*exec.ExitError); ok {
            ws := exitError.Sys().(syscall.WaitStatus)
            exitCode = ws.ExitStatus()
        } else {
            exitCode = 1
        }
    } else {
        ws := r.Process.ProcessState.Sys().(syscall.WaitStatus)
        exitCode = ws.ExitStatus()
    }

    if exitCode > 0 {
        log.Errorf("Canceling upload due to process failure - exitCode: %v", exitCode)
        r.Cancel()
    }

    return r.Parent.Close()
}