package etcd import ( "context" "log" "path" "strings" client "github.com/coreos/etcd/clientv3" cc "github.com/coreos/etcd/clientv3/concurrency" "github.com/micro/go-micro/v2/sync/leader" ) type etcdLeader struct { opts leader.Options path string client *client.Client } type etcdElected struct { s *cc.Session e *cc.Election id string } func (e *etcdLeader) Elect(id string, opts ...leader.ElectOption) (leader.Elected, error) { var options leader.ElectOptions for _, o := range opts { o(&options) } // make path path := path.Join(e.path, strings.Replace(id, "/", "-", -1)) s, err := cc.NewSession(e.client) if err != nil { return nil, err } l := cc.NewElection(s, path) if err := l.Campaign(context.TODO(), id); err != nil { return nil, err } return &etcdElected{ e: l, id: id, }, nil } func (e *etcdLeader) Follow() chan string { ch := make(chan string) s, err := cc.NewSession(e.client) if err != nil { return ch } l := cc.NewElection(s, e.path) ech := l.Observe(context.Background()) go func() { for r := range ech { ch <- string(r.Kvs[0].Value) } }() return ch } func (e *etcdLeader) String() string { return "etcd" } func (e *etcdElected) Reelect() error { return e.e.Campaign(context.TODO(), e.id) } func (e *etcdElected) Revoked() chan bool { ch := make(chan bool, 1) ech := e.e.Observe(context.Background()) go func() { for r := range ech { if string(r.Kvs[0].Value) != e.id { ch <- true close(ch) return } } }() return ch } func (e *etcdElected) Resign() error { return e.e.Resign(context.Background()) } func (e *etcdElected) Id() string { return e.id } func NewLeader(opts ...leader.Option) leader.Leader { var options leader.Options for _, o := range opts { o(&options) } var endpoints []string for _, addr := range options.Nodes { if len(addr) > 0 { endpoints = append(endpoints, addr) } } if len(endpoints) == 0 { endpoints = []string{"http://127.0.0.1:2379"} } // TODO: parse addresses c, err := client.New(client.Config{ Endpoints: endpoints, }) if err != nil { log.Fatal(err) } return &etcdLeader{ path: "/micro/leader", client: c, opts: options, } }