146 lines
2.3 KiB
Go
146 lines
2.3 KiB
Go
package etcd
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import (
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"context"
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"log"
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"path"
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"strings"
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client "github.com/coreos/etcd/clientv3"
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cc "github.com/coreos/etcd/clientv3/concurrency"
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"github.com/micro/go-micro/sync/leader"
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)
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type etcdLeader struct {
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opts leader.Options
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path string
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client *client.Client
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}
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type etcdElected struct {
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s *cc.Session
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e *cc.Election
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id string
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}
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func (e *etcdLeader) Elect(id string, opts ...leader.ElectOption) (leader.Elected, error) {
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var options leader.ElectOptions
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for _, o := range opts {
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o(&options)
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}
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// make path
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path := path.Join(e.path, strings.Replace(id, "/", "-", -1))
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s, err := cc.NewSession(e.client)
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if err != nil {
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return nil, err
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}
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l := cc.NewElection(s, path)
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ctx, _ := context.WithCancel(context.Background())
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if err := l.Campaign(ctx, id); err != nil {
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return nil, err
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}
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return &etcdElected{
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e: l,
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id: id,
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}, nil
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}
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func (e *etcdLeader) Follow() chan string {
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ch := make(chan string)
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s, err := cc.NewSession(e.client)
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if err != nil {
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return ch
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}
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l := cc.NewElection(s, e.path)
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ech := l.Observe(context.Background())
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go func() {
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for {
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select {
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case r, ok := <-ech:
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if !ok {
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return
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}
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ch <- string(r.Kvs[0].Value)
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}
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}
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}()
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return ch
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}
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func (e *etcdLeader) String() string {
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return "etcd"
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}
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func (e *etcdElected) Reelect() error {
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ctx, _ := context.WithCancel(context.Background())
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return e.e.Campaign(ctx, e.id)
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}
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func (e *etcdElected) Revoked() chan bool {
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ch := make(chan bool, 1)
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ech := e.e.Observe(context.Background())
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go func() {
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for r := range ech {
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if string(r.Kvs[0].Value) != e.id {
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ch <- true
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close(ch)
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return
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}
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}
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}()
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return ch
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}
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func (e *etcdElected) Resign() error {
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return e.e.Resign(context.Background())
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}
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func (e *etcdElected) Id() string {
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return e.id
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}
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func NewLeader(opts ...leader.Option) leader.Leader {
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var options leader.Options
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for _, o := range opts {
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o(&options)
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}
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var endpoints []string
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for _, addr := range options.Nodes {
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if len(addr) > 0 {
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endpoints = append(endpoints, addr)
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}
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}
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if len(endpoints) == 0 {
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endpoints = []string{"http://127.0.0.1:2379"}
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}
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// TODO: parse addresses
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c, err := client.New(client.Config{
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Endpoints: endpoints,
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})
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if err != nil {
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log.Fatal(err)
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}
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return &etcdLeader{
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path: "/micro/leader",
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client: c,
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opts: options,
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}
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}
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