forked from FeatureBaseDB/featurebase
/
gossip.go
242 lines (208 loc) · 6.49 KB
/
gossip.go
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// Copyright 2017 Pilosa Corp.
//
// 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 gossip
import (
"fmt"
"io"
"log"
"os"
"golang.org/x/sync/errgroup"
"github.com/gogo/protobuf/proto"
"github.com/hashicorp/memberlist"
"github.com/pilosa/pilosa"
"github.com/pilosa/pilosa/internal"
)
// GossipNodeSet represents a gossip implementation of NodeSet using memberlist
// GossipNodeSet also represents a gossip implementation of pilosa.Broadcaster
// GossipNodeSet also represents an implementation of memberlist.Delegate
type GossipNodeSet struct {
memberlist *memberlist.Memberlist
handler pilosa.BroadcastHandler
broadcasts *memberlist.TransmitLimitedQueue
statusHandler pilosa.StatusHandler
config *gossipConfig
// The writer for any logging.
LogOutput io.Writer
}
// Nodes implements the NodeSet interface and returns a list of nodes in the cluster.
func (g *GossipNodeSet) Nodes() []*pilosa.Node {
a := make([]*pilosa.Node, 0, g.memberlist.NumMembers())
for _, n := range g.memberlist.Members() {
a = append(a, &pilosa.Node{Host: n.Name})
}
return a
}
// Start implements the BroadcastReceiver interface and sets the BroadcastHandler
func (g *GossipNodeSet) Start(h pilosa.BroadcastHandler) error {
g.handler = h
return nil
}
// Open implements the NodeSet interface to start network activity.
func (g *GossipNodeSet) Open() error {
if g.handler == nil {
return fmt.Errorf("opening GossipNodeSet: you must call Start(pilosa.BroadcastHandler) before calling Open()")
}
ml, err := memberlist.Create(g.config.memberlistConfig)
if err != nil {
return err
}
g.memberlist = ml
// attach to gossip seed node
nodes := []*pilosa.Node{&pilosa.Node{Host: g.config.gossipSeed}} //TODO: support a list of seeds
_, err = g.memberlist.Join(pilosa.Nodes(nodes).Hosts())
if err != nil {
return err
}
g.broadcasts = &memberlist.TransmitLimitedQueue{
NumNodes: func() int {
return ml.NumMembers()
},
RetransmitMult: 3,
}
return nil
}
// logger returns a logger for the GossipNodeSet.
func (g *GossipNodeSet) logger() *log.Logger {
return log.New(g.LogOutput, "", log.LstdFlags)
}
////////////////////////////////////////////////////////////////
type gossipConfig struct {
gossipSeed string
memberlistConfig *memberlist.Config
}
// NewGossipNodeSet returns a new instance of GossipNodeSet.
func NewGossipNodeSet(name string, gossipHost string, gossipPort int, gossipSeed string, sh pilosa.StatusHandler) *GossipNodeSet {
g := &GossipNodeSet{
LogOutput: os.Stderr,
}
//TODO: pull memberlist config from pilosa.cfg file
g.config = &gossipConfig{
memberlistConfig: memberlist.DefaultLocalConfig(),
gossipSeed: gossipSeed,
}
g.config.memberlistConfig.Name = name
g.config.memberlistConfig.BindAddr = gossipHost
g.config.memberlistConfig.BindPort = gossipPort
g.config.memberlistConfig.AdvertiseAddr = gossipHost
g.config.memberlistConfig.AdvertisePort = gossipPort
g.config.memberlistConfig.Delegate = g
g.statusHandler = sh
return g
}
// SendSync implementation of the Broadcaster interface.
func (g *GossipNodeSet) SendSync(pb proto.Message) error {
msg, err := pilosa.MarshalMessage(pb)
if err != nil {
return err
}
mlist := g.memberlist
// Direct sends the message directly to every node.
// An error from any node raises an error on the entire operation.
//
// Gossip uses the gossip protocol to eventually deliver the message
// to every node.
var eg errgroup.Group
for _, n := range mlist.Members() {
// Don't send the message to the local node.
if n == mlist.LocalNode() {
continue
}
node := n
eg.Go(func() error {
return mlist.SendToTCP(node, msg)
})
}
return eg.Wait()
}
// SendAsync implementation of the Broadcaster interface.
func (g *GossipNodeSet) SendAsync(pb proto.Message) error {
msg, err := pilosa.MarshalMessage(pb)
if err != nil {
return err
}
b := &broadcast{
msg: msg,
notify: nil,
}
g.broadcasts.QueueBroadcast(b)
return nil
}
// NodeMeta implementation of the memberlist.Delegate interface.
func (g *GossipNodeSet) NodeMeta(limit int) []byte {
return []byte{}
}
// NotifyMsg implementation of the memberlist.Delegate interface
// called when a user-data message is received.
func (g *GossipNodeSet) NotifyMsg(b []byte) {
m, err := pilosa.UnmarshalMessage(b)
if err != nil {
g.logger().Printf("unmarshal message error: %s", err)
return
}
if err := g.handler.ReceiveMessage(m); err != nil {
g.logger().Printf("receive message error: %s", err)
return
}
}
// GetBroadcasts implementation of the memberlist.Delegate interface
// called when user data messages can be broadcast.
func (g *GossipNodeSet) GetBroadcasts(overhead, limit int) [][]byte {
return g.broadcasts.GetBroadcasts(overhead, limit)
}
// LocalState implementation of the memberlist.Delegate interface
// sends this Node's state data.
func (g *GossipNodeSet) LocalState(join bool) []byte {
pb, err := g.statusHandler.LocalStatus()
if err != nil {
g.logger().Printf("error getting local state, err=%s", err)
return []byte{}
}
// Marshal nodestate data to bytes.
buf, err := proto.Marshal(pb)
if err != nil {
g.logger().Printf("error marshalling nodestate data, err=%s", err)
return []byte{}
}
return buf
}
// MergeRemoteState implementation of the memberlist.Delegate interface
// receive and process the remote side side's LocalState.
func (g *GossipNodeSet) MergeRemoteState(buf []byte, join bool) {
// Unmarshal nodestate data.
var pb internal.NodeStatus
if err := proto.Unmarshal(buf, &pb); err != nil {
g.logger().Printf("error unmarshalling nodestate data, err=%s", err)
return
}
err := g.statusHandler.HandleRemoteStatus(&pb)
if err != nil {
g.logger().Printf("merge state error: %s", err)
}
}
// broadcast represents an implementation of memberlist.Broadcast
type broadcast struct {
msg []byte
notify chan<- struct{}
}
func (b *broadcast) Invalidates(other memberlist.Broadcast) bool {
return false
}
func (b *broadcast) Message() []byte {
return b.msg
}
func (b *broadcast) Finished() {
if b.notify != nil {
close(b.notify)
}
}