package warden import ( "fmt" "os" "os/exec" "path/filepath" "strings" "time" "github.com/samber/lo" ) var InstancePool []*AppInstance func GetFromPool(id string) *AppInstance { val, ok := lo.Find(InstancePool, func(item *AppInstance) bool { return item.Manifest.ID == id }) return lo.Ternary(ok, val, nil) } func StartPool() []error { var errors []error for _, instance := range InstancePool { if err := instance.Wake(); err != nil { errors = append(errors, err) } } return errors } type AppStatus = int8 const ( AppCreated = AppStatus(iota) AppStarting AppStarted AppExited AppFailure ) type AppInstance struct { Manifest Application `json:"manifest"` Cmd *exec.Cmd `json:"-"` Logger strings.Builder `json:"-"` Status AppStatus `json:"status"` } func (v *AppInstance) Wake() error { if v.Cmd != nil { return nil } if v.Cmd == nil { return v.Start() } if v.Cmd.Process == nil || v.Cmd.ProcessState == nil { return v.Start() } if v.Cmd.ProcessState.Exited() { return v.Start() } else if v.Cmd.ProcessState.Exited() { return fmt.Errorf("process already dead") } if v.Cmd.ProcessState.Exited() { return fmt.Errorf("cannot start process") } else { return nil } } func (v *AppInstance) Start() error { manifest := v.Manifest if len(manifest.Command) <= 0 { return fmt.Errorf("you need set the command for %s to enable process manager", manifest.ID) } v.Cmd = exec.Command(manifest.Command[0], manifest.Command[1:]...) v.Cmd.Dir = filepath.Join(manifest.Workdir) v.Cmd.Env = append(v.Cmd.Env, manifest.Environment...) v.Cmd.Stdout = &v.Logger v.Cmd.Stderr = &v.Logger // Monitor go func() { for { if v.Cmd.Process == nil || v.Cmd.ProcessState == nil { v.Status = AppStarting } else if !v.Cmd.ProcessState.Exited() { v.Status = AppStarted } else { v.Status = lo.Ternary(v.Cmd.ProcessState.Success(), AppExited, AppFailure) return } time.Sleep(100 * time.Millisecond) } }() return v.Cmd.Start() } func (v *AppInstance) Stop() error { if v.Cmd != nil && v.Cmd.Process != nil { if err := v.Cmd.Process.Signal(os.Interrupt); err != nil { v.Cmd.Process.Kill() return err } else { v.Cmd = nil } } return nil } func (v *AppInstance) Logs() string { return v.Logger.String() }