From 15e438aaa6ddfb4748547e9fb43060e3012b255c Mon Sep 17 00:00:00 2001
From: disksing <i@disksing.com>
Date: Mon, 16 Apr 2018 18:24:31 +0800
Subject: [PATCH 1/2] pdctl, api, schedule: pdctl supports scatter region.

---
 pdctl/command/operator.go           | 29 +++++++++++++++++++++++++++++
 server/api/operator.go              | 10 ++++++++++
 server/handler.go                   | 19 +++++++++++++++++++
 server/schedule/region_scatterer.go |  4 +++-
 4 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/pdctl/command/operator.go b/pdctl/command/operator.go
index 11bbbe70ced..b944e8086ce 100644
--- a/pdctl/command/operator.go
+++ b/pdctl/command/operator.go
@@ -80,6 +80,7 @@ func NewAddOperatorCommand() *cobra.Command {
 	c.AddCommand(NewRemovePeerCommand())
 	c.AddCommand(NewMergeRegionCommand())
 	c.AddCommand(NewSplitRegionCommand())
+	c.AddCommand(NewScatterRegionCommand())
 	return c
 }
 
@@ -286,6 +287,34 @@ func splitRegionCommandFunc(cmd *cobra.Command, args []string) {
 	postJSON(cmd, operatorsPrefix, input)
 }
 
+// NewScatterRegionCommand returns a command to scatter a region.
+func NewScatterRegionCommand() *cobra.Command {
+	c := &cobra.Command{
+		Use:   "scatter-region <region_id>",
+		Short: "scatter a region",
+		Run:   scatterRegionCommandFunc,
+	}
+	return c
+}
+
+func scatterRegionCommandFunc(cmd *cobra.Command, args []string) {
+	if len(args) != 1 {
+		fmt.Println(cmd.UsageString())
+		return
+	}
+
+	ids, err := parseUint64s(args)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+
+	input := make(map[string]interface{})
+	input["name"] = cmd.Name()
+	input["region_id"] = ids[0]
+	postJSON(cmd, operatorsPrefix, input)
+}
+
 // NewRemoveOperatorCommand returns a command to remove operators.
 func NewRemoveOperatorCommand() *cobra.Command {
 	c := &cobra.Command{
diff --git a/server/api/operator.go b/server/api/operator.go
index d880615f971..2be9c52e7a8 100644
--- a/server/api/operator.go
+++ b/server/api/operator.go
@@ -211,6 +211,16 @@ func (h *operatorHandler) Post(w http.ResponseWriter, r *http.Request) {
 			h.r.JSON(w, http.StatusInternalServerError, err.Error())
 			return
 		}
+	case "scatter-region":
+		regionID, ok := input["region_id"].(float64)
+		if !ok {
+			h.r.JSON(w, http.StatusBadRequest, "missing region id")
+			return
+		}
+		if err := h.AddScatterRegionOperator(uint64(regionID)); err != nil {
+			h.r.JSON(w, http.StatusInternalServerError, err.Error())
+			return
+		}
 	default:
 		h.r.JSON(w, http.StatusBadRequest, "unknown operator")
 		return
diff --git a/server/handler.go b/server/handler.go
index 0003774c4b6..1f8623d8324 100644
--- a/server/handler.go
+++ b/server/handler.go
@@ -520,6 +520,25 @@ func (h *Handler) AddSplitRegionOperator(regionID uint64) error {
 	return nil
 }
 
+// AddScatterRegionOperator adds an operator to scatter a region.
+func (h *Handler) AddScatterRegionOperator(regionID uint64) error {
+	c, err := h.getCoordinator()
+	if err != nil {
+		return errors.Trace(err)
+	}
+
+	region := c.cluster.GetRegion(regionID)
+	if region == nil {
+		return ErrRegionNotFound(regionID)
+	}
+
+	op := c.regionScatterer.Scatter(region)
+	if ok := c.addOperator(op); !ok {
+		return errors.Trace(errAddOperator)
+	}
+	return nil
+}
+
 // GetDownPeerRegions gets the region with down peer.
 func (h *Handler) GetDownPeerRegions() ([]*core.RegionInfo, error) {
 	c := h.s.GetRaftCluster()
diff --git a/server/schedule/region_scatterer.go b/server/schedule/region_scatterer.go
index d2655cbbb97..b179b8fed85 100644
--- a/server/schedule/region_scatterer.go
+++ b/server/schedule/region_scatterer.go
@@ -100,6 +100,7 @@ func (r *RegionScatterer) scatterRegion(region *core.RegionInfo) *Operator {
 	steps := make([]OperatorStep, 0, len(region.GetPeers()))
 
 	stores := r.collectAvailableStores(region)
+	var kind OperatorKind
 	for _, peer := range region.GetPeers() {
 		if len(stores) == 0 {
 			// Reset selected stores if we have no available stores.
@@ -124,12 +125,13 @@ func (r *RegionScatterer) scatterRegion(region *core.RegionInfo) *Operator {
 			peer.GetStoreId(), newPeer.GetStoreId(), newPeer.GetId())
 		steps = append(steps, op.steps...)
 		steps = append(steps, TransferLeader{ToStore: newPeer.GetStoreId()})
+		kind |= op.Kind()
 	}
 
 	if len(steps) == 0 {
 		return nil
 	}
-	return NewOperator("scatter-region", region.GetId(), OpAdmin, steps...)
+	return NewOperator("scatter-region", region.GetId(), kind, steps...)
 }
 
 func (r *RegionScatterer) selectPeerToReplace(stores map[uint64]*core.StoreInfo, region *core.RegionInfo, oldPeer *metapb.Peer) *metapb.Peer {

From 3289a21cd649439a4964825f288294528b66449b Mon Sep 17 00:00:00 2001
From: disksing <i@disksing.com>
Date: Tue, 17 Apr 2018 09:48:00 +0800
Subject: [PATCH 2/2] *: fix panic.

---
 server/handler.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/server/handler.go b/server/handler.go
index 1f8623d8324..2c2b47fd24b 100644
--- a/server/handler.go
+++ b/server/handler.go
@@ -533,6 +533,9 @@ func (h *Handler) AddScatterRegionOperator(regionID uint64) error {
 	}
 
 	op := c.regionScatterer.Scatter(region)
+	if op == nil {
+		return nil
+	}
 	if ok := c.addOperator(op); !ok {
 		return errors.Trace(errAddOperator)
 	}