152 lines
3.2 KiB
Go
152 lines
3.2 KiB
Go
package cluster
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import (
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"io/ioutil"
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baselog "log"
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"sort"
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"time"
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"github.com/lbryio/lbry.go/v2/extras/crypto"
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"github.com/lbryio/lbry.go/v2/extras/errors"
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"github.com/lbryio/lbry.go/v2/extras/stop"
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"github.com/hashicorp/serf/serf"
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log "github.com/sirupsen/logrus"
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)
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const (
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DefaultPort = 17946
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MembershipChangeBufferWindow = 1 * time.Second
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)
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// Cluster maintains cluster membership and notifies on certain events
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type Cluster struct {
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OnMembershipChange func(n, total int)
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name string
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port int
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seedAddr string
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s *serf.Serf
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eventCh chan serf.Event
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stop *stop.Group
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}
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// New returns a new Cluster instance that is not connected.
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func New(port int, seedAddr string) *Cluster {
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return &Cluster{
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name: crypto.RandString(12),
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port: port,
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seedAddr: seedAddr,
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stop: stop.New(),
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}
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}
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// Connect Initializes the Cluster based on a configuration passed via the New function. It then stores the seed
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// address, starts gossiping and listens for gossip.
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func (c *Cluster) Connect() error {
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var err error
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conf := serf.DefaultConfig()
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conf.MemberlistConfig.BindPort = c.port
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conf.MemberlistConfig.AdvertisePort = c.port
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conf.NodeName = c.name
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nullLogger := baselog.New(ioutil.Discard, "", 0)
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conf.Logger = nullLogger
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c.eventCh = make(chan serf.Event)
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conf.EventCh = c.eventCh
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c.s, err = serf.Create(conf)
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if err != nil {
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return errors.Prefix("couldn't create cluster", err)
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}
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if c.seedAddr != "" {
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_, err = c.s.Join([]string{c.seedAddr}, true)
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if err != nil {
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return err
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}
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}
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c.stop.Add(1)
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go func() {
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c.listen()
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c.stop.Done()
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}()
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log.Debugf("cluster started")
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return nil
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}
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// Shutdown safely shuts down the cluster.
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func (c *Cluster) Shutdown() {
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log.Debug("shutting down cluster...")
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c.stop.StopAndWait()
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err := c.s.Leave()
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if err != nil {
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log.Error(errors.Prefix("shutting down cluster", err))
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}
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log.Debugf("cluster stopped")
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}
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func (c *Cluster) listen() {
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var timerCh <-chan time.Time
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timer := time.NewTimer(0)
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for {
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select {
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case <-c.stop.Ch():
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return
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case event := <-c.eventCh:
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switch event.EventType() {
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case serf.EventMemberJoin, serf.EventMemberFailed, serf.EventMemberLeave:
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// // ignore event from my own joining of the cluster
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//memberEvent := event.(serf.MemberEvent)
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//if event.EventType() == serf.EventMemberJoin && len(memberEvent.Members) == 1 && memberEvent.Members[0].Name == c.name {
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// continue
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//}
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if timerCh == nil {
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timer.Reset(MembershipChangeBufferWindow)
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timerCh = timer.C
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}
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}
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case <-timerCh:
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if c.OnMembershipChange != nil {
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alive := getAliveMembers(c.s.Members())
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c.OnMembershipChange(getHashInterval(c.name, alive), len(alive))
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}
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timerCh = nil
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}
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}
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}
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func getHashInterval(myName string, members []serf.Member) int {
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var names []string
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for _, m := range members {
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names = append(names, m.Name)
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}
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sort.Strings(names)
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i := 1
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for _, n := range names {
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if n == myName {
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return i
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}
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i++
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}
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return -1
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}
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func getAliveMembers(members []serf.Member) []serf.Member {
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var alive []serf.Member
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for _, m := range members {
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if m.Status == serf.StatusAlive {
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alive = append(alive, m)
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}
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}
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return alive
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}
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