cluster: change return value for getSchedulers (#2615) (#2638)

Signed-off-by: Ryan Leung <rleungx@gmail.com>

server/cluster/cluster.go

@@ -1609,12 +1609,19 @@ func (c *RaftCluster) GetHotReadRegions() *statistics.StoreHotPeersInfos {
 }
 
 // GetSchedulers gets all schedulers.
-func (c *RaftCluster) GetSchedulers() map[string]*scheduleController {
+func (c *RaftCluster) GetSchedulers() []string {
 	c.RLock()
 	defer c.RUnlock()
 	return c.coordinator.getSchedulers()
 }
 
+// GetSchedulerHandlers gets all scheduler handlers.
+func (c *RaftCluster) GetSchedulerHandlers() map[string]http.Handler {
+	c.RLock()
+	defer c.RUnlock()
+	return c.coordinator.getSchedulerHandlers()
+}
+
 // AddScheduler adds a scheduler.
 func (c *RaftCluster) AddScheduler(scheduler schedule.Scheduler, args ...string) error {
 	c.Lock()
@@ -1636,6 +1643,13 @@ func (c *RaftCluster) PauseOrResumeScheduler(name string, t int64) error {
 	return c.coordinator.pauseOrResumeScheduler(name, t)
 }
 
+// IsSchedulerPaused checks if a scheduler is paused.
+func (c *RaftCluster) IsSchedulerPaused(name string) (bool, error) {
+	c.RLock()
+	defer c.RUnlock()
+	return c.coordinator.isSchedulerPaused(name)
+}
+
 // GetStoreLimiter returns the dynamic adjusting limiter
 func (c *RaftCluster) GetStoreLimiter() *StoreLimiter {
 	return c.limiter

server/cluster/coordinator.go

@@ -16,6 +16,7 @@ package cluster
 import (
 	"context"
 	"fmt"
+	"net/http"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -354,10 +355,24 @@ func (c *coordinator) getHotReadRegions() *statistics.StoreHotPeersInfos {
 	return nil
 }
 
-func (c *coordinator) getSchedulers() map[string]*scheduleController {
+func (c *coordinator) getSchedulers() []string {
 	c.RLock()
 	defer c.RUnlock()
-	return c.schedulers
+	names := make([]string, 0, len(c.schedulers))
+	for name := range c.schedulers {
+		names = append(names, name)
+	}
+	return names
+}
+
+func (c *coordinator) getSchedulerHandlers() map[string]http.Handler {
+	c.RLock()
+	defer c.RUnlock()
+	handlers := make(map[string]http.Handler, len(c.schedulers))
+	for name, scheduler := range c.schedulers {
+		handlers[name] = scheduler.Scheduler
+	}
+	return handlers
 }
 
 func (c *coordinator) collectSchedulerMetrics() {
@@ -535,6 +550,19 @@ func (c *coordinator) pauseOrResumeScheduler(name string, t int64) error {
 	return err
 }
 
+func (c *coordinator) isSchedulerPaused(name string) (bool, error) {
+	c.RLock()
+	defer c.RUnlock()
+	if c.cluster == nil {
+		return false, ErrNotBootstrapped
+	}
+	s, ok := c.schedulers[name]
+	if !ok {
+		return false, schedulers.ErrSchedulerNotFound
+	}
+	return s.IsPaused(), nil
+}
+
 func (c *coordinator) runScheduler(s *scheduleController) {
 	defer logutil.LogPanic()
 	defer c.wg.Done()

server/handler.go

@@ -102,15 +102,11 @@ func (h *Handler) GetOperatorController() (*schedule.OperatorController, error)
 
 // IsSchedulerPaused returns whether scheduler is paused.
 func (h *Handler) IsSchedulerPaused(name string) (bool, error) {
-	c, err := h.GetRaftCluster()
+	rc, err := h.GetRaftCluster()
 	if err != nil {
-		return true, err
-	}
-	sc, ok := c.GetSchedulers()[name]
-	if !ok {
-		return true, errors.Errorf("scheduler %v not found", name)
+		return false, err
 	}
-	return sc.IsPaused(), nil
+	return rc.IsSchedulerPaused(name)
 }
 
 // GetScheduleConfig returns ScheduleConfig.
@@ -124,11 +120,7 @@ func (h *Handler) GetSchedulers() ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	names := make([]string, 0, len(c.GetSchedulers()))
-	for name := range c.GetSchedulers() {
-		names = append(names, name)
-	}
-	return names, nil
+	return c.GetSchedulers(), nil
 }
 
 // GetStores returns all stores in the cluster.
@@ -805,7 +797,7 @@ func (h *Handler) GetSchedulerConfigHandler() http.Handler {
 		return nil
 	}
 	mux := http.NewServeMux()
-	for name, handler := range c.GetSchedulers() {
+	for name, handler := range c.GetSchedulerHandlers() {
 		prefix := path.Join(pdRootPath, SchedulerConfigHandlerPath, name)
 		urlPath := prefix + "/"
 		mux.Handle(urlPath, http.StripPrefix(prefix, handler))