Change Server API

* Rename ServerStatus to ServerState internally

* Rename terminate to shutdown internally

* Update Scheduler API to match Server API

scheduler.go

@@ -21,7 +21,7 @@ import (
 // A Scheduler kicks off tasks at regular intervals based on the user defined schedule.
 type Scheduler struct {
 	id         string
-	status     *base.ServerStatus
+	state      *base.ServerState
 	logger     *log.Logger
 	client     *Client
 	rdb        *rdb.RDB
@@ -61,7 +61,7 @@ func NewScheduler(r RedisConnOpt, opts *SchedulerOpts) *Scheduler {
 
 	return &Scheduler{
 		id:         generateSchedulerID(),
-		status:     base.NewServerStatus(base.StatusIdle),
+		state:      base.NewServerState(),
 		logger:     logger,
 		client:     NewClient(r),
 		rdb:        rdb.NewRDB(c),
@@ -170,22 +170,23 @@ func (s *Scheduler) Unregister(entryID string) error {
 }
 
 // Run starts the scheduler until an os signal to exit the program is received.
-// It returns an error if scheduler is already running or has been stopped.
+// It returns an error if scheduler is already running or has been shutdown.
 func (s *Scheduler) Run() error {
 	if err := s.Start(); err != nil {
 		return err
 	}
 	s.waitForSignals()
-	return s.Stop()
+	s.Shutdown()
+	return nil
 }
 
 // Start starts the scheduler.
-// It returns an error if the scheduler is already running or has been stopped.
+// It returns an error if the scheduler is already running or has been shutdown.
 func (s *Scheduler) Start() error {
-	switch s.status.Get() {
-	case base.StatusRunning:
+	switch s.state.Get() {
+	case base.StateActive:
 		return fmt.Errorf("asynq: the scheduler is already running")
-	case base.StatusStopped:
+	case base.StateClosed:
 		return fmt.Errorf("asynq: the scheduler has already been stopped")
 	}
 	s.logger.Info("Scheduler starting")
@@ -193,16 +194,12 @@ func (s *Scheduler) Start() error {
 	s.cron.Start()
 	s.wg.Add(1)
 	go s.runHeartbeater()
-	s.status.Set(base.StatusRunning)
+	s.state.Set(base.StateActive)
 	return nil
 }
 
-// Stop stops the scheduler.
-// It returns an error if the scheduler is not currently running.
-func (s *Scheduler) Stop() error {
-	if s.status.Get() != base.StatusRunning {
-		return fmt.Errorf("asynq: the scheduler is not running")
-	}
+// Shutdown stops and shuts down the scheduler.
+func (s *Scheduler) Shutdown() {
 	s.logger.Info("Scheduler shutting down")
 	close(s.done) // signal heartbeater to stop
 	ctx := s.cron.Stop()
@@ -212,9 +209,8 @@ func (s *Scheduler) Stop() error {
 	s.clearHistory()
 	s.client.Close()
 	s.rdb.Close()
-	s.status.Set(base.StatusStopped)
+	s.state.Set(base.StateClosed)
 	s.logger.Info("Scheduler stopped")
-	return nil
 }
 
 func (s *Scheduler) runHeartbeater() {