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etcdclient.go
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etcdclient.go
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// Copyright 2016 CodisLabs. All Rights Reserved.
// Licensed under the MIT (MIT-LICENSE.txt) license.
package etcdclient
import (
"strings"
"sync"
"time"
"golang.org/x/net/context"
"github.com/coreos/etcd/client"
"github.com/CodisLabs/codis/pkg/utils/errors"
"github.com/CodisLabs/codis/pkg/utils/log"
)
var ErrClosedClient = errors.New("use of closed etcd client")
var (
ErrNotDir = errors.New("etcd: not a dir")
ErrNotFile = errors.New("etcd: not a file")
)
type Client struct {
sync.Mutex
kapi client.KeysAPI
closed bool
timeout time.Duration
cancel context.CancelFunc
context context.Context
}
func New(addrlist string, timeout time.Duration) (*Client, error) {
endpoints := strings.Split(addrlist, ",")
for i, s := range endpoints {
if s != "" && !strings.HasPrefix(s, "http://") {
endpoints[i] = "http://" + s
}
}
if timeout <= 0 {
timeout = time.Second * 5
}
c, err := client.New(client.Config{
Endpoints: endpoints, Transport: client.DefaultTransport,
HeaderTimeoutPerRequest: time.Second * 5,
})
if err != nil {
return nil, errors.Trace(err)
}
client := &Client{
kapi: client.NewKeysAPI(c), timeout: timeout,
}
client.context, client.cancel = context.WithCancel(context.Background())
return client, nil
}
func (c *Client) Close() error {
c.Lock()
defer c.Unlock()
if c.closed {
return nil
}
c.closed = true
c.cancel()
return nil
}
func (c *Client) newContext() (context.Context, context.CancelFunc) {
return context.WithTimeout(c.context, c.timeout)
}
func isErrNoNode(err error) bool {
if err != nil {
if e, ok := err.(client.Error); ok {
return e.Code == client.ErrorCodeKeyNotFound
}
}
return false
}
func isErrNodeExists(err error) bool {
if err != nil {
if e, ok := err.(client.Error); ok {
return e.Code == client.ErrorCodeNodeExist
}
}
return false
}
func (c *Client) Mkdir(path string) error {
c.Lock()
defer c.Unlock()
if c.closed {
return errors.Trace(ErrClosedClient)
}
log.Debugf("etcd mkdir node %s", path)
cntx, cancel := c.newContext()
defer cancel()
_, err := c.kapi.Set(cntx, path, "", &client.SetOptions{Dir: true, PrevExist: client.PrevNoExist})
if err != nil && !isErrNodeExists(err) {
log.Debugf("etcd mkdir node %s failed: %s", path, err)
return errors.Trace(err)
}
log.Debugf("etcd mkdir OK")
return nil
}
func (c *Client) Create(path string, data []byte) error {
c.Lock()
defer c.Unlock()
if c.closed {
return errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd create node %s", path)
_, err := c.kapi.Set(cntx, path, string(data), &client.SetOptions{PrevExist: client.PrevNoExist})
if err != nil {
log.Debugf("etcd create node %s failed: %s", path, err)
return errors.Trace(err)
}
log.Debugf("etcd create OK")
return nil
}
func (c *Client) Update(path string, data []byte) error {
c.Lock()
defer c.Unlock()
if c.closed {
return errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd update node %s", path)
_, err := c.kapi.Set(cntx, path, string(data), &client.SetOptions{PrevExist: client.PrevIgnore})
if err != nil {
log.Debugf("etcd update node %s failed: %s", path, err)
return errors.Trace(err)
}
log.Debugf("etcd update OK")
return nil
}
func (c *Client) Delete(path string) error {
c.Lock()
defer c.Unlock()
if c.closed {
return errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd delete node %s", path)
_, err := c.kapi.Delete(cntx, path, nil)
if err != nil && !isErrNoNode(err) {
log.Debugf("etcd delete node %s failed: %s", path, err)
return errors.Trace(err)
}
log.Debugf("etcd delete OK")
return nil
}
func (c *Client) Read(path string, must bool) ([]byte, error) {
c.Lock()
defer c.Unlock()
if c.closed {
return nil, errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
r, err := c.kapi.Get(cntx, path, &client.GetOptions{Quorum: true})
switch {
case err != nil:
if isErrNoNode(err) && !must {
return nil, nil
}
log.Debugf("etcd read node %s failed: %s", path, err)
return nil, errors.Trace(err)
case !r.Node.Dir:
return []byte(r.Node.Value), nil
default:
log.Debugf("etcd read node %s failed: not a file", path)
return nil, errors.Trace(ErrNotFile)
}
}
func (c *Client) List(path string, must bool) ([]string, error) {
c.Lock()
defer c.Unlock()
if c.closed {
return nil, errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
r, err := c.kapi.Get(cntx, path, &client.GetOptions{Quorum: true})
switch {
case err != nil:
if isErrNoNode(err) && !must {
return nil, nil
}
log.Debugf("etcd list node %s failed: %s", path, err)
return nil, errors.Trace(err)
case !r.Node.Dir:
log.Debugf("etcd list node %s failed: not a dir", path)
return nil, errors.Trace(ErrNotDir)
default:
var paths []string
for _, node := range r.Node.Nodes {
paths = append(paths, node.Key)
}
return paths, nil
}
}
func (c *Client) CreateEphemeral(path string, data []byte) (<-chan struct{}, error) {
c.Lock()
defer c.Unlock()
if c.closed {
return nil, errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd create-ephemeral node %s", path)
_, err := c.kapi.Set(cntx, path, string(data), &client.SetOptions{PrevExist: client.PrevNoExist, TTL: c.timeout})
if err != nil {
log.Debugf("etcd create-ephemeral node %s failed: %s", path, err)
return nil, errors.Trace(err)
}
log.Debugf("etcd create-ephemeral OK")
return runRefreshEphemeral(c, path), nil
}
func (c *Client) CreateEphemeralInOrder(path string, data []byte) (<-chan struct{}, string, error) {
c.Lock()
defer c.Unlock()
if c.closed {
return nil, "", errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd create-ephemeral-inorder node %s", path)
r, err := c.kapi.CreateInOrder(cntx, path, string(data), &client.CreateInOrderOptions{TTL: c.timeout})
if err != nil {
log.Debugf("etcd create-ephemeral-inorder node %s failed: %s", path, err)
return nil, "", errors.Trace(err)
}
node := r.Node.Key
log.Debugf("etcd create-ephemeral-inorder OK, node = %s", node)
return runRefreshEphemeral(c, node), node, nil
}
func runRefreshEphemeral(c *Client, path string) <-chan struct{} {
signal := make(chan struct{})
go func() {
defer close(signal)
for {
if err := c.RefreshEphemeral(path); err != nil {
return
} else {
time.Sleep(c.timeout / 2)
}
}
}()
return signal
}
func (c *Client) RefreshEphemeral(path string) error {
c.Lock()
defer c.Unlock()
if c.closed {
return errors.Trace(ErrClosedClient)
}
cntx, cancel := c.newContext()
defer cancel()
log.Debugf("etcd refresh-ephemeral node %s", path)
_, err := c.kapi.Set(cntx, path, "", &client.SetOptions{PrevExist: client.PrevExist, Refresh: true, TTL: c.timeout})
if err != nil {
log.Debugf("etcd refresh-ephemeral node %s failed: %s", path, err)
return errors.Trace(err)
}
log.Debugf("etcd refresh-ephemeral OK")
return nil
}
func (c *Client) WatchInOrder(path string) (<-chan struct{}, []string, error) {
if err := c.Mkdir(path); err != nil {
return nil, nil, err
}
c.Lock()
defer c.Unlock()
if c.closed {
return nil, nil, errors.Trace(ErrClosedClient)
}
log.Debugf("etcd watch-inorder node %s", path)
cntx, cancel := c.newContext()
defer cancel()
r, err := c.kapi.Get(cntx, path, &client.GetOptions{Quorum: true, Sort: true})
switch {
case err != nil:
log.Debugf("etcd watch-inorder node %s failed: %s", path, err)
return nil, nil, errors.Trace(err)
case !r.Node.Dir:
log.Debugf("etcd watch-inorder node %s failed: not a dir", path)
return nil, nil, errors.Trace(ErrNotDir)
}
var index = r.Index
var paths []string
for _, node := range r.Node.Nodes {
paths = append(paths, node.Key)
}
signal := make(chan struct{})
go func() {
defer close(signal)
watch := c.kapi.Watcher(path, &client.WatcherOptions{AfterIndex: index})
for {
r, err := watch.Next(c.context)
switch {
case err != nil:
log.Debugf("etch watch-inorder node %s failed: %s", path, err)
return
case r.Action != "get":
log.Debugf("etcd watch-inorder node %s update", path)
return
}
}
}()
log.Debugf("etcd watch-inorder OK")
return signal, paths, nil
}