testAndSet.go

package etcd

import (
	"encoding/json"
	"fmt"
	"github.com/coreos/etcd/store"
	"io/ioutil"
	"net/http"
	"net/url"
	"path"
)

func (c *Client) TestAndSet(key string, prevValue string, value string, ttl uint64) (*store.Response, bool, error) {
	logger.Debugf("set %s, %s[%s], ttl: %d, [%s]", key, value, prevValue, ttl, c.cluster.Leader)
	v := url.Values{}
	v.Set("value", value)
	v.Set("prevValue", prevValue)

	if ttl > 0 {
		v.Set("ttl", fmt.Sprintf("%v", ttl))
	}

	resp, err := c.sendRequest("POST", path.Join("keys", key), v.Encode())

	if err != nil {
		return nil, false, err
	}

	b, err := ioutil.ReadAll(resp.Body)

	resp.Body.Close()

	if err != nil {

		return nil, false, err
	}

	if resp.StatusCode != http.StatusOK {
		return nil, false, handleError(b)
	}

	var result store.Response

	err = json.Unmarshal(b, &result)

	if err != nil {
		return nil, false, err
	}

	if result.PrevValue == prevValue && result.Value == value {

		return &result, true, nil
	}

	return &result, false, nil

}