forked from huichen/consistent_service
/
consistent_service.go
81 lines (70 loc) · 1.84 KB
/
consistent_service.go
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package consistent_service
import (
"errors"
"log"
"stathat.com/c/consistent"
"time"
"github.com/coreos/etcd/Godeps/_workspace/src/golang.org/x/net/context"
"github.com/coreos/etcd/client"
)
type ConsistentService struct {
consis *consistent.Consistent
etcdClient client.Client
connected bool
}
func (service *ConsistentService) watch(watcher client.Watcher) {
for {
resp, err := watcher.Next(context.Background())
if err == nil {
if resp.Action == "set" {
n := resp.Node.Value
service.consis.Add(n)
} else if resp.Action == "delete" {
n := resp.PrevNode.Value
service.consis.Remove(n)
}
}
}
}
// serviceName is like "/services/busybox"
// endPoints is an array of "http://<etcd client ip:port>"
func (service *ConsistentService) Connect(serviceName string, endPoints []string) error {
if service.connected {
log.Printf("Can't connected twice")
return errors.New("math: square root of negative number")
}
service.consis = consistent.New()
cfg := client.Config{
Endpoints: endPoints,
Transport: client.DefaultTransport,
HeaderTimeoutPerRequest: time.Second,
}
var err error
service.etcdClient, err = client.New(cfg)
if err != nil {
return err
}
kapi := client.NewKeysAPI(service.etcdClient)
resp, err := kapi.Get(context.Background(), serviceName, nil)
if err != nil {
return err
} else {
if resp.Node.Dir {
for _, peer := range resp.Node.Nodes {
n := peer.Value
service.consis.Add(n)
}
}
}
watcher := kapi.Watcher(serviceName, &client.WatcherOptions{Recursive: true})
go service.watch(watcher)
service.connected = true
return nil
}
func (service *ConsistentService) GetNode(key string) (string, error) {
if !service.connected {
return "", errors.New("Must call connect before Hash")
}
node, err := service.consis.Get(key)
return node, err
}