dragonboat: get ready for the v3.1 release

CHANGELOG.md

@@ -1,3 +1,24 @@
+## v3.1 (2019-07-04)
+
+Dragonboat v3.1 is a maintenance release with breaking change. All v3.0.x users are recommended to upgrade. Please make sure to carefully read the CHANGELOG below before upgrading.
+
+### Bug fixes
+
+- Fixed ImportSnapshot. 
+
+### New features
+
+- Added NodeHostConfig.RaftEventListener to allow user applications to be notified for certain Raft events.
+
+### Improvements
+
+- Made restarting an existing node faster.
+- Immediately return ErrClusterNotReady when requests are dropped for not having a leader.
+
+### Breaking changes
+
+- When upgrading to v3.1.x from v3.0.x, dragonboat requires all streamed or imported snapshots to have been applied. github.com/lni/dragonboat/tools/upgrade310 has been provided to check that. See the godoc in github.com/lni/dragonboat/tools/upgrade310 for more details. For users who use NodeHost.RequestSnapshot to export snapshots for backup purposes, we recommend to re-generate all exported snapshots once upgraded to v3.1.
+
 ## v3.0 (2019-06-21)
 
 Dragonboat v3.0 is a major release with breaking changes. Please make sure to carefully read the CHANGELOG below before upgrading.

event.go

@@ -16,20 +16,23 @@ package dragonboat
 
 import (
 	"fmt"
-	"io"
 	"sync/atomic"
 
 	"github.com/VictoriaMetrics/metrics"
 	"github.com/lni/dragonboat/v3/internal/server"
 	"github.com/lni/dragonboat/v3/raftio"
 )
 
+// WriteHealthMetrics is disabled for v3.1
+
+/*
 // WriteHealthMetrics writes all health metrics in Prometheus format to the
 // specified writer. This function is typically called by the metrics http
 // handler.
 func WriteHealthMetrics(w io.Writer) {
 	metrics.WritePrometheus(w, false)
 }
+*/
 
 type raftEventListener struct {
 	clusterID           uint64

nodehost.go

@@ -115,7 +115,7 @@ const (
 	// DragonboatPatch is the patch version number
 	DragonboatPatch = 0
 	// DEVVersion is a boolean flag indicating whether this is a dev version
-	DEVVersion = true
+	DEVVersion = false
 )
 
 var (
@@ -576,7 +576,7 @@ func (nh *NodeHost) SyncGetClusterMembership(ctx context.Context,
 // its confirmed completion, failure or timeout.
 //
 // Deprecated: Use NodeHost.SyncGetClusterMembership instead.
-// NodeHost.GetClusterMembership will be removed in v3.1.
+// NodeHost.GetClusterMembership will be removed in v3.2.
 func (nh *NodeHost) GetClusterMembership(ctx context.Context,
 	clusterID uint64) (*Membership, error) {
 	return nh.SyncGetClusterMembership(ctx, clusterID)
@@ -625,7 +625,7 @@ func (nh *NodeHost) GetNoOPSession(clusterID uint64) *client.Session {
 // multiple client sessions when making concurrent proposals.
 //
 // Deprecated: Use NodeHost.SyncGetSession instead. NodeHost.GetNewSession will
-// be removed in v3.1.
+// be removed in v3.2.
 func (nh *NodeHost) GetNewSession(ctx context.Context,
 	clusterID uint64) (*client.Session, error) {
 	return nh.SyncGetSession(ctx, clusterID)
@@ -639,7 +639,7 @@ func (nh *NodeHost) GetNewSession(ctx context.Context,
 // Closed client session should no longer be used in future proposals.
 //
 // Deprecated: Use NodeHost.SyncCloseSession instead. NodeHost.CloseSession will
-// be removed in v3.1.
+// be removed in v3.2
 func (nh *NodeHost) CloseSession(ctx context.Context,
 	session *client.Session) error {
 	return nh.SyncCloseSession(ctx, session)