micro/sync/etcd/etcd.go

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2020-04-11 10:37:54 +01:00
// Package etcd is an etcd implementation of lock
package etcd
import (
"context"
"errors"
"log"
"path"
"strings"
gosync "sync"
client "github.com/coreos/etcd/clientv3"
cc "github.com/coreos/etcd/clientv3/concurrency"
"github.com/unistack-org/micro/v3/sync"
2020-04-11 10:37:54 +01:00
)
type etcdSync struct {
options sync.Options
path string
client *client.Client
mtx gosync.Mutex
locks map[string]*etcdLock
}
type etcdLock struct {
s *cc.Session
m *cc.Mutex
}
type etcdLeader struct {
opts sync.LeaderOptions
s *cc.Session
e *cc.Election
id string
}
func (e *etcdSync) Leader(id string, opts ...sync.LeaderOption) (sync.Leader, error) {
var options sync.LeaderOptions
for _, o := range opts {
o(&options)
}
// make path
path := path.Join(e.path, strings.Replace(e.options.Prefix+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 &etcdLeader{
opts: options,
e: l,
id: id,
}, nil
}
func (e *etcdLeader) Status() 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 *etcdLeader) Resign() error {
return e.e.Resign(context.Background())
}
func (e *etcdSync) Init(opts ...sync.Option) error {
for _, o := range opts {
o(&e.options)
}
return nil
}
func (e *etcdSync) Options() sync.Options {
return e.options
}
func (e *etcdSync) Lock(id string, opts ...sync.LockOption) error {
var options sync.LockOptions
for _, o := range opts {
o(&options)
}
// make path
path := path.Join(e.path, strings.Replace(e.options.Prefix+id, "/", "-", -1))
var sopts []cc.SessionOption
if options.TTL > 0 {
sopts = append(sopts, cc.WithTTL(int(options.TTL.Seconds())))
}
s, err := cc.NewSession(e.client, sopts...)
if err != nil {
return err
}
m := cc.NewMutex(s, path)
if err := m.Lock(context.TODO()); err != nil {
return err
}
e.mtx.Lock()
e.locks[id] = &etcdLock{
s: s,
m: m,
}
e.mtx.Unlock()
return nil
}
func (e *etcdSync) Unlock(id string) error {
e.mtx.Lock()
defer e.mtx.Unlock()
v, ok := e.locks[id]
if !ok {
return errors.New("lock not found")
}
err := v.m.Unlock(context.Background())
delete(e.locks, id)
return err
}
func (e *etcdSync) String() string {
return "etcd"
}
func NewSync(opts ...sync.Option) sync.Sync {
var options sync.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 &etcdSync{
path: "/micro/sync",
client: c,
options: options,
locks: make(map[string]*etcdLock),
}
}