Merge pull request #2540 from xiang90/raft-progress

raft: move progress to progress.go

raft/progress.go

@@ -0,0 +1,151 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package raft
+
+import "fmt"
+
+const (
+	ProgressStateProbe ProgressStateType = iota
+	ProgressStateReplicate
+	ProgressStateSnapshot
+)
+
+type ProgressStateType uint64
+
+var prstmap = [...]string{
+	"ProgressStateProbe",
+	"ProgressStateReplicate",
+	"ProgressStateSnapshot",
+}
+
+func (st ProgressStateType) String() string { return prstmap[uint64(st)] }
+
+// Progress represents a follower’s progress in the view of the leader. Leader maintains
+// progresses of all followers, and sends entries to the follower based on its progress.
+type Progress struct {
+	Match, Next uint64
+	// When in ProgressStateProbe, leader sends at most one replication message
+	// per heartbeat interval. It also probes actual progress of the follower.
+	//
+	// When in ProgressStateReplicate, leader optimistically increases next
+	// to the latest entry sent after sending replication message. This is
+	// an optimized state for fast replicating log entries to the follower.
+	//
+	// When in ProgressStateSnapshot, leader should have sent out snapshot
+	// before and stops sending any replication message.
+	State ProgressStateType
+	// Paused is used in ProgressStateProbe.
+	// When Paused is true, raft should pause sending replication message to this peer.
+	Paused bool
+	// PendingSnapshot is used in ProgressStateSnapshot.
+	// If there is a pending snapshot, the pendingSnapshot will be set to the
+	// index of the snapshot. If pendingSnapshot is set, the replication process of
+	// this Progress will be paused. raft will not resend snapshot until the pending one
+	// is reported to be failed.
+	PendingSnapshot uint64
+}
+
+func (pr *Progress) resetState(state ProgressStateType) {
+	pr.Paused = false
+	pr.PendingSnapshot = 0
+	pr.State = state
+}
+
+func (pr *Progress) becomeProbe() {
+	// If the original state is ProgressStateSnapshot, progress knows that
+	// the pending snapshot has been sent to this peer successfully, then
+	// probes from pendingSnapshot + 1.
+	if pr.State == ProgressStateSnapshot {
+		pendingSnapshot := pr.PendingSnapshot
+		pr.resetState(ProgressStateProbe)
+		pr.Next = max(pr.Match+1, pendingSnapshot+1)
+	} else {
+		pr.resetState(ProgressStateProbe)
+		pr.Next = pr.Match + 1
+	}
+}
+
+func (pr *Progress) becomeReplicate() {
+	pr.resetState(ProgressStateReplicate)
+	pr.Next = pr.Match + 1
+}
+
+func (pr *Progress) becomeSnapshot(snapshoti uint64) {
+	pr.resetState(ProgressStateSnapshot)
+	pr.PendingSnapshot = snapshoti
+}
+
+// maybeUpdate returns false if the given n index comes from an outdated message.
+// Otherwise it updates the progress and returns true.
+func (pr *Progress) maybeUpdate(n uint64) bool {
+	var updated bool
+	if pr.Match < n {
+		pr.Match = n
+		updated = true
+		pr.resume()
+	}
+	if pr.Next < n+1 {
+		pr.Next = n + 1
+	}
+	return updated
+}
+
+func (pr *Progress) optimisticUpdate(n uint64) { pr.Next = n + 1 }
+
+// maybeDecrTo returns false if the given to index comes from an out of order message.
+// Otherwise it decreases the progress next index to min(rejected, last) and returns true.
+func (pr *Progress) maybeDecrTo(rejected, last uint64) bool {
+	if pr.State == ProgressStateReplicate {
+		// the rejection must be stale if the progress has matched and "rejected"
+		// is smaller than "match".
+		if rejected <= pr.Match {
+			return false
+		}
+		// directly decrease next to match + 1
+		pr.Next = pr.Match + 1
+		return true
+	}
+
+	// the rejection must be stale if "rejected" does not match next - 1
+	if pr.Next-1 != rejected {
+		return false
+	}
+
+	if pr.Next = min(rejected, last+1); pr.Next < 1 {
+		pr.Next = 1
+	}
+	pr.resume()
+	return true
+}
+
+func (pr *Progress) pause()  { pr.Paused = true }
+func (pr *Progress) resume() { pr.Paused = false }
+
+// isPaused returns whether progress stops sending message.
+func (pr *Progress) isPaused() bool {
+	return pr.State == ProgressStateProbe && pr.Paused || pr.State == ProgressStateSnapshot
+}
+
+func (pr *Progress) snapshotFailure() { pr.PendingSnapshot = 0 }
+
+// maybeSnapshotAbort unsets pendingSnapshot if Match is equal or higher than
+// the pendingSnapshot
+func (pr *Progress) maybeSnapshotAbort() bool {
+	return pr.State == ProgressStateSnapshot && pr.Match >= pr.PendingSnapshot
+}
+
+func (pr *Progress) String() string {
+	return fmt.Sprintf("next = %d, match = %d, state = %s, waiting = %v, pendingSnapshot = %d", pr.Next, pr.Match, pr.State, pr.isPaused(), pr.PendingSnapshot)
+}

raft/raft.go

@@ -51,138 +51,6 @@ func (st StateType) String() string {
 	return stmap[uint64(st)]
 }
 
-const (
-	ProgressStateProbe ProgressStateType = iota
-	ProgressStateReplicate
-	ProgressStateSnapshot
-)
-
-type ProgressStateType uint64
-
-var prstmap = [...]string{
-	"ProgressStateProbe",
-	"ProgressStateReplicate",
-	"ProgressStateSnapshot",
-}
-
-func (st ProgressStateType) String() string { return prstmap[uint64(st)] }
-
-type Progress struct {
-	Match, Next uint64
-	// When in ProgressStateProbe, leader sends at most one replication message
-	// per heartbeat interval. It also probes actual progress of the follower.
-	//
-	// When in ProgressStateReplicate, leader optimistically increases next
-	// to the latest entry sent after sending replication message. This is
-	// an optimized state for fast replicating log entries to the follower.
-	//
-	// When in ProgressStateSnapshot, leader should have sent out snapshot
-	// before and stops sending any replication message.
-	State ProgressStateType
-	// Paused is used in ProgressStateProbe.
-	// When Paused is true, raft should pause sending replication message to this peer.
-	Paused bool
-	// PendingSnapshot is used in ProgressStateSnapshot.
-	// If there is a pending snapshot, the pendingSnapshot will be set to the
-	// index of the snapshot. If pendingSnapshot is set, the replication process of
-	// this Progress will be paused. raft will not resend snapshot until the pending one
-	// is reported to be failed.
-	PendingSnapshot uint64
-}
-
-func (pr *Progress) resetState(state ProgressStateType) {
-	pr.Paused = false
-	pr.PendingSnapshot = 0
-	pr.State = state
-}
-
-func (pr *Progress) becomeProbe() {
-	// If the original state is ProgressStateSnapshot, progress knows that
-	// the pending snapshot has been sent to this peer successfully, then
-	// probes from pendingSnapshot + 1.
-	if pr.State == ProgressStateSnapshot {
-		pendingSnapshot := pr.PendingSnapshot
-		pr.resetState(ProgressStateProbe)
-		pr.Next = max(pr.Match+1, pendingSnapshot+1)
-	} else {
-		pr.resetState(ProgressStateProbe)
-		pr.Next = pr.Match + 1
-	}
-}
-
-func (pr *Progress) becomeReplicate() {
-	pr.resetState(ProgressStateReplicate)
-	pr.Next = pr.Match + 1
-}
-
-func (pr *Progress) becomeSnapshot(snapshoti uint64) {
-	pr.resetState(ProgressStateSnapshot)
-	pr.PendingSnapshot = snapshoti
-}
-
-// maybeUpdate returns false if the given n index comes from an outdated message.
-// Otherwise it updates the progress and returns true.
-func (pr *Progress) maybeUpdate(n uint64) bool {
-	var updated bool
-	if pr.Match < n {
-		pr.Match = n
-		updated = true
-		pr.resume()
-	}
-	if pr.Next < n+1 {
-		pr.Next = n + 1
-	}
-	return updated
-}
-
-func (pr *Progress) optimisticUpdate(n uint64) { pr.Next = n + 1 }
-
-// maybeDecrTo returns false if the given to index comes from an out of order message.
-// Otherwise it decreases the progress next index to min(rejected, last) and returns true.
-func (pr *Progress) maybeDecrTo(rejected, last uint64) bool {
-	if pr.State == ProgressStateReplicate {
-		// the rejection must be stale if the progress has matched and "rejected"
-		// is smaller than "match".
-		if rejected <= pr.Match {
-			return false
-		}
-		// directly decrease next to match + 1
-		pr.Next = pr.Match + 1
-		return true
-	}
-
-	// the rejection must be stale if "rejected" does not match next - 1
-	if pr.Next-1 != rejected {
-		return false
-	}
-
-	if pr.Next = min(rejected, last+1); pr.Next < 1 {
-		pr.Next = 1
-	}
-	pr.resume()
-	return true
-}
-
-func (pr *Progress) pause()  { pr.Paused = true }
-func (pr *Progress) resume() { pr.Paused = false }
-
-// isPaused returns whether progress stops sending message.
-func (pr *Progress) isPaused() bool {
-	return pr.State == ProgressStateProbe && pr.Paused || pr.State == ProgressStateSnapshot
-}
-
-func (pr *Progress) snapshotFailure() { pr.PendingSnapshot = 0 }
-
-// maybeSnapshotAbort unsets pendingSnapshot if Match is equal or higher than
-// the pendingSnapshot
-func (pr *Progress) maybeSnapshotAbort() bool {
-	return pr.State == ProgressStateSnapshot && pr.Match >= pr.PendingSnapshot
-}
-
-func (pr *Progress) String() string {
-	return fmt.Sprintf("next = %d, match = %d, state = %s, waiting = %v, pendingSnapshot = %d", pr.Next, pr.Match, pr.State, pr.isPaused(), pr.PendingSnapshot)
-}
-
 type raft struct {
 	pb.HardState