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binding_storage.go
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binding_storage.go
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// Copyright (c) TFG Co. All Rights Reserved.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
package modules
import (
"context"
"fmt"
"time"
"github.com/coreos/etcd/clientv3"
"github.com/coreos/etcd/clientv3/namespace"
"github.com/topfreegames/pitaya/cluster"
"github.com/topfreegames/pitaya/config"
"github.com/topfreegames/pitaya/constants"
"github.com/topfreegames/pitaya/logger"
"github.com/topfreegames/pitaya/session"
)
// ETCDBindingStorage module that uses etcd to keep in which frontend server each user is bound
type ETCDBindingStorage struct {
Base
config *config.Config
cli *clientv3.Client
etcdEndpoints []string
etcdPrefix string
etcdDialTimeout time.Duration
leaseTTL time.Duration
leaseID clientv3.LeaseID
thisServer *cluster.Server
stopChan chan struct{}
}
// NewETCDBindingStorage returns a new instance of BindingStorage
func NewETCDBindingStorage(server *cluster.Server, conf *config.Config) *ETCDBindingStorage {
b := &ETCDBindingStorage{
config: conf,
thisServer: server,
stopChan: make(chan struct{}),
}
b.configure()
return b
}
func (b *ETCDBindingStorage) configure() {
b.etcdDialTimeout = b.config.GetDuration("pitaya.modules.bindingstorage.etcd.dialtimeout")
b.etcdEndpoints = b.config.GetStringSlice("pitaya.modules.bindingstorage.etcd.endpoints")
b.etcdPrefix = b.config.GetString("pitaya.modules.bindingstorage.etcd.prefix")
b.leaseTTL = b.config.GetDuration("pitaya.modules.bindingstorage.etcd.leasettl")
}
func getUserBindingKey(uid, frontendType string) string {
return fmt.Sprintf("bindings/%s/%s", frontendType, uid)
}
// PutBinding puts the binding info into etcd
func (b *ETCDBindingStorage) PutBinding(uid string) error {
_, err := b.cli.Put(context.Background(), getUserBindingKey(uid, b.thisServer.Type), b.thisServer.ID, clientv3.WithLease(b.leaseID))
return err
}
func (b *ETCDBindingStorage) removeBinding(uid string) error {
_, err := b.cli.Delete(context.Background(), getUserBindingKey(uid, b.thisServer.Type))
return err
}
// GetUserFrontendID gets the id of the frontend server a user is connected to
// TODO: should we set context here?
// TODO: this could be way more optimized, using watcher and local caching
func (b *ETCDBindingStorage) GetUserFrontendID(uid, frontendType string) (string, error) {
etcdRes, err := b.cli.Get(context.Background(), getUserBindingKey(uid, frontendType))
if err != nil {
return "", err
}
if len(etcdRes.Kvs) == 0 {
return "", constants.ErrBindingNotFound
}
return string(etcdRes.Kvs[0].Value), nil
}
func (b *ETCDBindingStorage) setupOnSessionCloseCB() {
session.OnSessionClose(func(s *session.Session) {
if s.UID() != "" {
err := b.removeBinding(s.UID())
if err != nil {
logger.Log.Errorf("error removing binding info from storage: %v", err)
}
}
})
}
func (b *ETCDBindingStorage) setupOnAfterSessionBindCB() {
session.OnAfterSessionBind(func(ctx context.Context, s *session.Session) error {
return b.PutBinding(s.UID())
})
}
func (b *ETCDBindingStorage) watchLeaseChan(c <-chan *clientv3.LeaseKeepAliveResponse) {
for {
select {
case <-b.stopChan:
return
case kaRes := <-c:
if kaRes == nil {
logger.Log.Warn("[binding storage] sd: error renewing etcd lease, rebootstrapping")
for {
err := b.bootstrapLease()
if err != nil {
logger.Log.Warn("[binding storage] sd: error rebootstrapping lease, will retry in 5 seconds")
time.Sleep(5 * time.Second)
continue
} else {
return
}
}
}
}
}
}
func (b *ETCDBindingStorage) bootstrapLease() error {
// grab lease
l, err := b.cli.Grant(context.TODO(), int64(b.leaseTTL.Seconds()))
if err != nil {
return err
}
b.leaseID = l.ID
logger.Log.Debugf("[binding storage] sd: got leaseID: %x", l.ID)
// this will keep alive forever, when channel c is closed
// it means we probably have to rebootstrap the lease
c, err := b.cli.KeepAlive(context.TODO(), b.leaseID)
if err != nil {
return err
}
// need to receive here as per etcd docs
<-c
go b.watchLeaseChan(c)
return nil
}
// Init starts the binding storage module
func (b *ETCDBindingStorage) Init() error {
var cli *clientv3.Client
var err error
if b.cli == nil {
cli, err = clientv3.New(clientv3.Config{
Endpoints: b.etcdEndpoints,
DialTimeout: b.etcdDialTimeout,
})
if err != nil {
return err
}
b.cli = cli
}
// namespaced etcd :)
b.cli.KV = namespace.NewKV(b.cli.KV, b.etcdPrefix)
err = b.bootstrapLease()
if err != nil {
return err
}
if b.thisServer.Frontend {
b.setupOnSessionCloseCB()
b.setupOnAfterSessionBindCB()
}
return nil
}
// Shutdown executes on shutdown and will clean etcd
func (b *ETCDBindingStorage) Shutdown() error {
close(b.stopChan)
return b.cli.Close()
}