Golang Client.Get方法代码示例

// CanConnect checks a given SSH key against the list of authorized users in etcd
// to check if a user with a given key is allowed to connect. It takes in an active
// etcd.Client struct pointer and the ssh key to test and returns a username
// and boolean representing if they are allowed to connect.
func CanConnect(e *etcd.Client, sshkey string) (user string, allowed bool) {
	reply, err := e.Get("/flitter/builder/users/", true, true)

	if err != nil {
		log.Printf("etcd: %s", err)
		return "", false
	}

	keybit := strings.Split(sshkey, " ")[1]
	fp := GetFingerprint(keybit)

	for _, userdir := range reply.Node.Nodes {
		for _, fpnode := range userdir.Nodes {
			thisFpSplit := strings.Split(fpnode.Key, "/")
			thisFp := thisFpSplit[len(thisFpSplit)-1]

			if fp == thisFp {
				userpath := strings.Split(userdir.Key, "/")
				user := userpath[len(userpath)-1]
				return user, true
			}
		}
	}

	return
}

// acquireOrRenewLease either races to acquire a new master lease, or update the existing master's lease
// returns true if we have the lease, and an error if one occurs.
// TODO: use the master election utility once it is merged in.
func (c *Config) acquireOrRenewLease(etcdClient *etcd.Client) (bool, error) {
	result, err := etcdClient.Get(c.key, false, false)
	if err != nil {
		if tools.IsEtcdNotFound(err) {
			// there is no current master, try to become master, create will fail if the key already exists
			_, err := etcdClient.Create(c.key, c.whoami, c.ttl)
			if err != nil {
				return false, err
			}
			c.lastLease = time.Now()
			return true, nil
		}
		return false, err
	}
	if result.Node.Value == c.whoami {
		glog.Infof("key already exists, we are the master (%s)", result.Node.Value)
		// we extend our lease @ 1/2 of the existing TTL, this ensures the master doesn't flap around
		if result.Node.Expiration.Sub(time.Now()) < time.Duration(c.ttl/2)*time.Second {
			_, err := etcdClient.CompareAndSwap(c.key, c.whoami, c.ttl, c.whoami, result.Node.ModifiedIndex)
			if err != nil {
				return false, err
			}
		}
		c.lastLease = time.Now()
		return true, nil
	}
	glog.Infof("key already exists, the master is %s, sleeping.", result.Node.Value)
	return false, nil
}

func GetIndex(client *etcd.Client, basedir string, jobname string, ip string) (int, error) {
	jobdir := "/jobs" + "/" + jobname
	response, err := client.Get(jobdir, true, true)
	if err == nil {
		for i := 0; i < response.Node.Nodes.Len(); i++ {
			if response.Node.Nodes[i].Value == ip {
				return i, nil
			}
		}
	}
	response, err = client.AddChild(jobdir, ip, 0)
	if err != nil {
		fmt.Printf("use etcd to get index error: %v\n", err)
		return 0, err
	}
	mykey := response.Node.Key
	response, err = client.Get(jobdir, true, true)
	if err != nil {
		fmt.Printf("get etcd jobdir error: %v\n", err)
		return 0, err
	}
	for i := 0; i < response.Node.Nodes.Len(); i++ {
		if response.Node.Nodes[i].Key == mykey {
			return i, nil
		}
	}
	// this line would never reach.
	return 0, errors.New("etcd add child error!")
}

// getAddress will return the host:port address of the service taking care of
// the task that we want to talk to.
// Currently we grab the information from etcd every time. Local cache could be used.
// If it failed, e.g. network failure, it should return error.
func GetAddress(client *etcd.Client, name string, id uint64) (string, error) {
	resp, err := client.Get(TaskMasterPath(name, id), false, false)
	if err != nil {
		return "", err
	}
	return resp.Node.Value, nil
}

// latestRunningVersion retrieves the highest version of the application published
// to etcd. If no app has been published, returns 0.
func latestRunningVersion(client *etcd.Client, appName string) int {
	r := regexp.MustCompile(appNameRegex)
	if client == nil {
		// FIXME: client should only be nil during tests. This should be properly refactored.
		if appName == "ceci-nest-pas-une-app" {
			return 3
		}
		return 0
	}
	resp, err := client.Get(fmt.Sprintf("/deis/services/%s", appName), false, true)
	if err != nil {
		// no app has been published here (key not found) or there was an error
		return 0
	}
	var versions []int
	for _, node := range resp.Node.Nodes {
		match := r.FindStringSubmatch(node.Key)
		// account for keys that may not be an application container
		if match == nil {
			continue
		}
		version, err := strconv.Atoi(match[2])
		if err != nil {
			log.Println(err)
			return 0
		}
		versions = append(versions, version)
	}
	return max(versions)
}

func GetAndWatchEpoch(client *etcd.Client, appname string, epochC chan uint64, stop chan bool) (uint64, error) {
	resp, err := client.Get(EpochPath(appname), false, false)
	if err != nil {
		log.Fatal("etcdutil: can not get epoch from etcd")
	}
	ep, err := strconv.ParseUint(resp.Node.Value, 10, 64)
	if err != nil {
		return 0, err
	}
	receiver := make(chan *etcd.Response, 1)
	go client.Watch(EpochPath(appname), resp.EtcdIndex+1, false, receiver, stop)
	go func() {
		for resp := range receiver {
			if resp.Action != "compareAndSwap" && resp.Action != "set" {
				continue
			}
			epoch, err := strconv.ParseUint(resp.Node.Value, 10, 64)
			if err != nil {
				log.Fatal("etcdutil: can't parse epoch from etcd")
			}
			epochC <- epoch
		}
	}()

	return ep, nil
}

func getRuntimeConfFromEtcd(client *etcd.Client, etcd_path string) (*RuntimeConfig, error) {
	resp, err := client.Get(etcd_path, false, false)
	if err != nil {
		return nil, fmt.Errorf("failed to get RuntimeConfig:%v", err)
	}
	r := bytes.NewReader([]byte(resp.Node.Value))
	return ReadRuntimeConfig(r)
}

// On any change we just refresh everything
func handleChange(etcdClient *etcd.Client) {

	resp, err := etcdClient.Get(etcdWatchKey, false, true)
	if err != nil {
		fmt.Println(err)
		return
	}

	// Go and fetch all the services in REDIS
	redisClient := clients.RedisClient()
	if (redisClient == nil) {
		fmt.Println("Couldn't connect to redis")
		return
	}
	defer redisClient.Close()

	keys, err := redis.Strings(redisClient.Do("KEYS", "frontend:*"))
	if err != nil {
		fmt.Println(err)
		return
	}

	// Now we delete everything in redis and add everything back in from etcd
	redisClient.Send("MULTI")
	if len(keys) > 0 {
		redisClient.Send("DEL", redis.Args{}.AddFlat(keys)...)
	}

	for _, node := range resp.Node.Nodes {
		// This first level is a frontend
		split := strings.Split(node.Key, "/")
		domain := split[len(split) - 1]

		frontendKey := "frontend:" + domain

		// Belt and braces - delete this key just in case its not already (but it should be)
		redisClient.Send("DEL", frontendKey)
		redisClient.Send("RPUSH", frontendKey, domain)

		for _, instNode := range node.Nodes {
			instsplit := strings.Split(instNode.Key, "/")
			inst := instsplit[len(instsplit) - 1]
			host := "http://" + inst
			redisClient.Send("RPUSH", frontendKey, host)
		}
	}

	// Should be everything
	_, err = redisClient.Do("EXEC")
	if err != nil {
		fmt.Println(err)
		return
	}

	fmt.Println("Resynced hipache from etcd")
}

func getEtcdRoute(client *etcd.Client) *Route {
	hostResp, err := client.Get("/deis/logs/host", false, false)
	assert(err, "url")
	portResp, err := client.Get("/deis/logs/port", false, false)
	assert(err, "url")
	protocol := getEtcdValueOrDefault(client, "/deis/logs/protocol", "udp")
	host := fmt.Sprintf("%s:%s", hostResp.Node.Value, portResp.Node.Value)
	log.Printf("routing all to %s://%s", protocol, host)
	return &Route{ID: "etcd", Target: Target{Type: "syslog", Addr: host, Protocol: protocol}}
}

func getEtcdValueOrDefault(c *etcd.Client, key string, defaultValue string) string {
	resp, err := c.Get(key, false, false)
	if err != nil {
		if strings.Contains(fmt.Sprintf("%v", err), "Key not found") {
			return defaultValue
		}
		assert(err, "url")
	}
	return resp.Node.Value
}

func get(e *etcd.Client, q string, t uint16) ([]dns.RR, error) {
	path := questionToPath(q, t)
	r, err := e.Get(path, false, false)
	if err != nil {
		return nil, err
	}
	h := dns.RR_Header{Name: q, Rrtype: t, Class: dns.ClassINET, Ttl: 60} // Ttl is overridden
	rr := parseValue(t, r.Node.Value, h)
	return []dns.RR{rr}, nil
}

func getCurrentVersion(client *etcd.Client, key string) *etcd.Response {
	for {
		if resp, err := client.Get(key, false, false); err == nil {
			// failed to fetch first value
			return resp
		} else {
			time.Sleep(time.Second)
		}
	}
}

func loadConfig(client *etcd.Client, config *server.Config) error {
	// Override what isn't set yet from the command line.
	n, err := client.Get("/"+msg.PathPrefix+"/config", false, false)
	if err != nil {
		log.Printf("skydns: falling back to default configuration, could not read from etcd: %s", err)
		return nil
	}
	if err := json.Unmarshal([]byte(n.Node.Value), config); err != nil {
		return fmt.Errorf("failed to unmarshal config: %s", err.Error())
	}
	return nil
}

// WaitFreeTask blocks until it gets a hint of free task
func WaitFreeTask(client *etcd.Client, name string, logger *log.Logger) (uint64, error) {
	slots, err := client.Get(FreeTaskDir(name), false, true)
	if err != nil {
		return 0, err
	}
	if total := len(slots.Node.Nodes); total > 0 {
		ri := rand.Intn(total)
		s := slots.Node.Nodes[ri]
		idStr := path.Base(s.Key)
		id, err := strconv.ParseUint(idStr, 0, 64)
		if err != nil {
			return 0, err
		}
		logger.Printf("got free task %v, randomly choose %d to try...", ListKeys(slots.Node.Nodes), ri)
		return id, nil
	}

	watchIndex := slots.EtcdIndex + 1
	respChan := make(chan *etcd.Response, 1)
	go func() {
		for {
			logger.Printf("start to wait failure at index %d", watchIndex)
			resp, err := client.Watch(FreeTaskDir(name), watchIndex, true, nil, nil)
			if err != nil {
				logger.Printf("WARN: WaitFailure watch failed: %v", err)
				return
			}
			if resp.Action == "set" {
				respChan <- resp
				return
			}
			watchIndex = resp.EtcdIndex + 1
		}
	}()
	var resp *etcd.Response
	var waitTime uint64 = 0
	for {
		select {
		case resp = <-respChan:
			idStr := path.Base(resp.Node.Key)
			id, err := strconv.ParseUint(idStr, 10, 64)
			if err != nil {
				return 0, err
			}
			return id, nil
		case <-time.After(10 * time.Second):
			waitTime++
			logger.Printf("Node already wait failure for %d0s", waitTime)
		}
	}

}

// TestEtcdClient verifies a client is functional.  It will attempt to
// connect to the etcd server and block until the server responds at least once, or return an
// error if the server never responded.
func TestEtcdClient(etcdClient *etcdclient.Client) error {
	for i := 0; ; i++ {
		_, err := etcdClient.Get("/", false, false)
		if err == nil || etcdutil.IsEtcdNotFound(err) {
			break
		}
		if i > 100 {
			return fmt.Errorf("could not reach etcd: %v", err)
		}
		time.Sleep(50 * time.Millisecond)
	}
	return nil
}