/
etcd_plugin.go
192 lines (154 loc) · 4.23 KB
/
etcd_plugin.go
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package grpc_discover
import (
"context"
"log"
"sync"
"time"
"github.com/pkg/errors"
clientv3 "go.etcd.io/etcd/client/v3"
"google.golang.org/grpc/resolver"
)
type ETCDPlugin struct {
client *clientv3.Client
kv clientv3.KV
watcher clientv3.Watcher
lease clientv3.Lease
mu sync.Mutex
mapping map[string]clientv3.LeaseID
}
// NewETCDPlugin 初始化 etcd 插件,Initialize etcd plugin
func NewETCDPlugin(config clientv3.Config) (*ETCDPlugin, error) {
client, err := clientv3.New(config)
if err != nil {
return nil, err
}
kv := clientv3.NewKV(client)
watcher := clientv3.NewWatcher(client)
lease := clientv3.NewLease(client)
return &ETCDPlugin{
client: client,
kv: kv,
watcher: watcher,
lease: lease,
mapping: map[string]clientv3.LeaseID{},
}, nil
}
// Register 服务注册
func (e *ETCDPlugin) Register(serverName string, address string) (serverID string, err error) {
e.mu.Lock()
defer e.mu.Unlock()
serverID = getServerID(serverName)
leaseID, err := e.lease.Grant(context.TODO(), 10)
if err != nil {
return "", err
}
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
_, err = e.kv.Put(ctx, serverID, address, clientv3.WithLease(leaseID.ID))
if err != nil {
return "", err
}
ch, err := e.lease.KeepAlive(context.TODO(), leaseID.ID)
if err != nil {
return "", err
}
go func() {
for {
select {
case <-ch:
}
}
}()
e.mapping[serverID] = leaseID.ID
log.Printf("[GRPC Discover][ETCD Pugin] Register ServerName: %s ServerAddress: %s ServerID: %s \n", serverName, address, serverID)
return serverID, nil
}
// UnRegister 服务反注册
func (e *ETCDPlugin) UnRegister(serverID string) error {
e.mu.Lock()
defer e.mu.Unlock()
id, ex := e.mapping[serverID]
if !ex {
return errors.New("service does not exist")
}
_, err := e.kv.Delete(context.TODO(), serverID)
if err != nil {
return err
}
_, err = e.lease.Revoke(context.TODO(), id)
return err
}
// AutoUnRegister 自动退出
func (e *ETCDPlugin) AutoUnRegister(serverID string) {
Signal(func() {
e.UnRegister(serverID)
})
}
func (e *ETCDPlugin) DiscoverByServerName(serverName string) ([]string, error) {
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
get, err := e.kv.Get(ctx, getServerIDPrefix(serverName), clientv3.WithPrefix())
if err != nil {
return nil, err
}
var srvAddress []string
for _, v := range get.Kvs {
srvAddress = append(srvAddress, string(v.Value))
}
return srvAddress, nil
}
func (e *ETCDPlugin) DiscoverByServerID(serverID string) (string, error) {
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
get, err := e.kv.Get(ctx, serverID)
if err != nil {
return "", err
}
if len(get.Kvs) != 1 {
return "", ErrServiceNotFound
}
return string(get.Kvs[0].Value), nil
}
func (e *ETCDPlugin) Build(target resolver.Target, cc resolver.ClientConn, opts resolver.BuildOptions) (resolver.Resolver, error) {
r := &etcdResolver{
target: target,
cc: cc,
opts: opts,
e: e,
}
r.ResolveNow(resolver.ResolveNowOptions{})
return r, nil
}
func (e *ETCDPlugin) Scheme() string {
return "etcd"
}
type etcdResolver struct {
target resolver.Target
cc resolver.ClientConn
opts resolver.BuildOptions
e *ETCDPlugin
}
func (e *etcdResolver) ResolveNow(options resolver.ResolveNowOptions) {
ctx, cancel := context.WithTimeout(context.Background(), 3*time.Second)
defer cancel()
get, err := e.e.kv.Get(ctx, getServerIDPrefix(e.target.Endpoint), clientv3.WithPrefix())
if err != nil {
log.Printf("[GRPC Discover][ETCD Pugin] ResolveNow %s:///%s Error: %s \n", e.target.Scheme, e.target.Endpoint, err)
return
}
if get.Count == 0 {
log.Printf("[GRPC Discover][ETCD Pugin] ResolveNow %s:///%s Error: %s \n", e.target.Scheme, e.target.Endpoint, "could not find service")
return
}
var srvAddress []resolver.Address
for _, v := range get.Kvs {
srvAddress = append(srvAddress, resolver.Address{
Addr: string(v.Value),
})
}
err = e.cc.UpdateState(resolver.State{Addresses: srvAddress})
if err != nil {
log.Printf("[GRPC Discover][ETCD Pugin] ResolveNow %s:///%s Error: %s \n", e.target.Scheme, e.target.Endpoint, err)
}
}
func (e *etcdResolver) Close() {}