add service lifecycle module (#9)

* fix mock file (#3)

Co-authored-by: DylanYong <dylan.y@nodereal.io>

* add service lifecycle module


Co-authored-by: DylanYong <dylan.y@nodereal.io>

pkg/lifecycle/README.md

@@ -0,0 +1,42 @@
+# Service Lifecycle
+
+This package provides useful method to manage the lifecycle of a service or a group of services with convenient initializations of components.
+
+## Interface
+
+```go
+type Service interface {
+	Name() string
+	Start(ctx context.Context) error
+	Stop(ctx context.Context) error
+}
+```
+
+## Feature
+
+- Start and stop a group of services
+- Monitor signals to stop services
+- Graceful shutdown
+
+## Example
+
+```go
+package main
+
+import (
+	"context"
+	"syscall"
+	"time"
+
+	"github.com/bnb-chain/inscription-storage-provider/pkg/lifecycle"
+	"http_server"
+	"rpc_server"
+)
+
+func main() {
+	ctx := context.Background()
+	l := lifecycle.NewService(5 * time.Second)
+	l.RegisterServices(http_server, rpc_server)
+	l.Signals(syscall.SIGINT, syscall.SIGTERM).Init(ctx).StartServices(ctx).Wait(ctx)
+}
+```

pkg/lifecycle/lifecycle.go

@@ -0,0 +1,124 @@
+package lifecycle
+
+import (
+	"context"
+	"errors"
+	"os"
+	"os/signal"
+	"time"
+
+	"github.com/bnb-chain/inscription-storage-provider/util/log"
+)
+
+// Service provides abstract methods to control the lifecycle of a service
+//
+//go:generate mockgen -source=./lifecycle.go -destination=./mock/lifecycle_mock.go -package=mock
+type Service interface {
+	// Name describe service name
+	Name() string
+	// Start a service, this method should be used in non-block form
+	Start(ctx context.Context) error
+	// Stop a service, this method should be used in non-block form
+	Stop(ctx context.Context) error
+}
+
+// ServiceLifecycle manages services' lifecycle
+type ServiceLifecycle struct {
+	innerCtx    context.Context
+	innerCancel context.CancelFunc
+	services    []Service
+	timeout     time.Duration
+}
+
+// NewService returns an initialized service lifecycle
+func NewService(timeout time.Duration) *ServiceLifecycle {
+	innerCtx, innerCancel := context.WithCancel(context.Background())
+	return &ServiceLifecycle{
+		innerCtx:    innerCtx,
+		innerCancel: innerCancel,
+		timeout:     timeout,
+	}
+}
+
+// RegisterServices register services of an application
+func (s *ServiceLifecycle) RegisterServices(services ...Service) {
+	s.services = append(s.services, services...)
+}
+
+// StartServices starts running services
+func (s *ServiceLifecycle) StartServices(ctx context.Context) *ServiceLifecycle {
+	s.start(ctx)
+	return s
+}
+
+func (s *ServiceLifecycle) start(ctx context.Context) {
+	for i, service := range s.services {
+		if err := service.Start(ctx); err != nil {
+			log.Errorf("Service %s starts error: %v", service.Name(), err)
+			s.services = s.services[:i]
+			s.innerCancel()
+			break
+		} else {
+			log.Infof("Service %s starts successfully", service.Name())
+		}
+	}
+}
+
+// Signals registers monitor signals
+func (s *ServiceLifecycle) Signals(sigs ...os.Signal) *ServiceLifecycle {
+	go s.signals(sigs...)
+	return s
+}
+
+func (s *ServiceLifecycle) signals(sigs ...os.Signal) {
+	sigCh := make(chan os.Signal, 1)
+	signal.Notify(sigCh, sigs...)
+	for {
+		select {
+		case <-s.innerCtx.Done():
+			return
+		case sig := <-sigCh:
+			for _, j := range sigs {
+				if j == sig {
+					s.innerCancel()
+					return
+				}
+			}
+		}
+	}
+}
+
+// Wait blocks until context is done
+func (s *ServiceLifecycle) Wait(ctx context.Context) {
+	<-s.innerCtx.Done()
+	s.StopServices(ctx)
+}
+
+// StopServices stop services when context is done or timeout
+func (s *ServiceLifecycle) StopServices(ctx context.Context) {
+	gCtx, cancel := context.WithTimeout(context.Background(), s.timeout)
+	s.stop(ctx, cancel)
+
+	<-gCtx.Done()
+	if errors.Is(gCtx.Err(), context.Canceled) {
+		log.Infow("Services stop working", "service config timeout", s.timeout)
+	} else if errors.Is(gCtx.Err(), context.DeadlineExceeded) {
+		log.Error("Timeout while stopping service, killing instance manually")
+	}
+}
+
+func (s *ServiceLifecycle) stop(ctx context.Context, cancel context.CancelFunc) {
+	for _, service := range s.services {
+		if err := service.Stop(ctx); err != nil {
+			log.Errorf("Service %s stops failure: %v", service.Name(), err)
+		} else {
+			log.Infof("Service %s stops successfully!", service.Name())
+		}
+	}
+	cancel()
+}
+
+// Done check context is done
+func (s *ServiceLifecycle) Done() <-chan struct{} {
+	return s.innerCtx.Done()
+}

pkg/lifecycle/lifecycle_test.go

@@ -0,0 +1,8 @@
+package lifecycle
+
+import "testing"
+
+// TODO(VM):Make up later
+func Test(t *testing.T) {
+
+}