♻️ Refactored process manager

pkg/warden/executor.go

@@ -0,0 +1,101 @@
+package warden
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/samber/lo"
+)
+
+type AppStatus = int8
+
+const (
+	AppCreated = AppStatus(iota)
+	AppStarting
+	AppStarted
+	AppExited
+	AppFailure
+)
+
+type WardenInstance struct {
+	Manifest WardenApplication `json:"manifest"`
+
+	Cmd    *exec.Cmd       `json:"-"`
+	Logger strings.Builder `json:"-"`
+
+	Status AppStatus `json:"status"`
+}
+
+func (v *WardenInstance) 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 *WardenInstance) 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 *WardenInstance) 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 *WardenInstance) Logs() string {
+	return v.Logger.String()
+}

pkg/warden/manifest.go

@@ -0,0 +1,8 @@
+package warden
+
+type WardenApplication struct {
+	ID          string   `json:"id" yaml:"id"`
+	Workdir     string   `json:"workdir" yaml:"workdir"`
+	Command     []string `json:"command" yaml:"command"`
+	Environment []string `json:"environment" yaml:"environment"`
+}