/
peergroup.go
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/
peergroup.go
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// Copyright 2019-present Open Networking Foundation.
//
// 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 (
"context"
"github.com/atomix/atomix-go-framework/pkg/atomix/cluster"
"github.com/atomix/atomix-go-framework/pkg/atomix/errors"
"github.com/atomix/atomix-go-framework/pkg/atomix/meta"
"github.com/atomix/atomix-go-framework/pkg/atomix/time"
"github.com/atomix/atomix-go-framework/pkg/atomix/util/async"
"sync"
)
func NewPeerGroup(partition *Partition, serviceID ServiceId, clock time.Clock, replicas int) (*PeerGroup, error) {
var localMemberID MemberID
member, ok := partition.Partition.Member()
if ok {
localMemberID = MemberID(member.ID)
}
group := &PeerGroup{
memberID: localMemberID,
partition: partition,
serviceID: serviceID,
clock: clock,
replicas: replicas,
}
if err := group.start(); err != nil {
return nil, err
}
return group, nil
}
type PeerGroup struct {
memberID MemberID
partition *Partition
serviceID ServiceId
peersByID map[PeerID]*Peer
peers []*Peer
peersMu sync.RWMutex
clock time.Clock
replicas int
cancel context.CancelFunc
}
func (g *PeerGroup) start() error {
ctx, cancel := context.WithCancel(context.Background())
g.cancel = cancel
watchCh := make(chan cluster.ReplicaSet)
err := g.partition.Watch(ctx, watchCh)
if err != nil {
return err
}
replicaSet := g.partition.Replicas()
err = g.updatePeers(replicaSet)
if err != nil {
return err
}
go g.watchReplicas(watchCh)
return nil
}
func (g *PeerGroup) watchReplicas(watchCh <-chan cluster.ReplicaSet) {
for replicaSet := range watchCh {
err := g.updatePeers(replicaSet)
if err != nil {
log.Errorf("Failed to handle replica set change: %v", err)
}
}
}
func (g *PeerGroup) updatePeers(replicas cluster.ReplicaSet) error {
g.peersMu.Lock()
defer g.peersMu.Unlock()
replicationFactor := g.replicas
if replicationFactor == 0 || replicationFactor > len(replicas) {
replicationFactor = len(replicas)
}
peers := make([]*Peer, 0, len(g.peers)+1)
peersByID := make(map[PeerID]*Peer)
for i := 0; i < replicationFactor; i++ {
replica := replicas[i]
if member, ok := g.partition.Member(); !ok || replica.ID == member.ID {
continue
}
peer, ok := g.peersByID[PeerID(replica.ID)]
if !ok {
p, err := newPeer(g, replica, g.clock)
if err != nil {
return err
}
peer = p
}
peers = append(peers, peer)
peersByID[peer.ID] = peer
}
g.peers = peers
g.peersByID = peersByID
return nil
}
func (g *PeerGroup) MemberID() MemberID {
return g.memberID
}
func (g *PeerGroup) Peer(id PeerID) *Peer {
return g.peersByID[id]
}
func (g *PeerGroup) Peers() []*Peer {
g.peersMu.RLock()
defer g.peersMu.RUnlock()
return g.peers
}
func (g *PeerGroup) Read(ctx context.Context, key string) ([]Object, error) {
g.peersMu.RLock()
peers := g.peers
g.peersMu.RUnlock()
results, err := async.ExecuteAsync(len(peers), func(i int) (interface{}, error) {
peer := peers[i]
return peer.Read(ctx, key)
})
if err != nil {
return nil, errors.From(err)
}
objects := make([]Object, 0, len(results))
for _, result := range results {
if result != nil {
objects = append(objects, *result.(*Object))
}
}
return objects, nil
}
func (g *PeerGroup) ReadAll(ctx context.Context, ch chan<- Object) error {
g.peersMu.RLock()
peers := g.peers
g.peersMu.RUnlock()
wg := &sync.WaitGroup{}
wg.Add(len(peers))
err := async.IterAsync(len(peers), func(i int) error {
peer := peers[i]
peerCh := make(chan Object)
err := peer.ReadAll(ctx, peerCh)
if err != nil {
return err
}
for object := range peerCh {
ch <- object
}
wg.Done()
return nil
})
if err != nil {
return errors.From(err)
}
go func() {
wg.Wait()
close(ch)
}()
return nil
}
func (g *PeerGroup) Advertise(ctx context.Context, key string, digest meta.ObjectMeta) {
g.peersMu.RLock()
peers := g.peers
g.peersMu.RUnlock()
for _, peer := range peers {
peer.Advertise(ctx, key, digest)
}
}
func (g *PeerGroup) Update(ctx context.Context, object *Object) {
g.peersMu.RLock()
peers := g.peers
g.peersMu.RUnlock()
for _, peer := range peers {
peer.Update(ctx, object)
}
}
func (g *PeerGroup) Close() {
g.cancel()
}