api: Implement bucket notification. (#2271)

* Implement basic S3 notifications through queues

Supports multiple queues and three basic queue types:

1. NilQueue -- messages don't get sent anywhere
2. LogQueue -- messages get logged
3. AmqpQueue -- messages are sent to an AMQP queue

* api: Implement bucket notification.

Supports two different queue types

- AMQP
- ElasticSearch.

* Add support for redis

vendor/gopkg.in/olivere/elastic.v3/ping.go

@@ -0,0 +1,126 @@
+// Copyright 2012-2015 Oliver Eilhard. All rights reserved.
+// Use of this source code is governed by a MIT-license.
+// See http://olivere.mit-license.org/license.txt for details.
+
+package elastic
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/url"
+)
+
+// PingService checks if an Elasticsearch server on a given URL is alive.
+// When asked for, it can also return various information about the
+// Elasticsearch server, e.g. the Elasticsearch version number.
+//
+// Ping simply starts a HTTP GET request to the URL of the server.
+// If the server responds with HTTP Status code 200 OK, the server is alive.
+type PingService struct {
+	client       *Client
+	url          string
+	timeout      string
+	httpHeadOnly bool
+	pretty       bool
+}
+
+// PingResult is the result returned from querying the Elasticsearch server.
+type PingResult struct {
+	Name        string `json:"name"`
+	ClusterName string `json:"cluster_name"`
+	Version     struct {
+		Number         string `json:"number"`
+		BuildHash      string `json:"build_hash"`
+		BuildTimestamp string `json:"build_timestamp"`
+		BuildSnapshot  bool   `json:"build_snapshot"`
+		LuceneVersion  string `json:"lucene_version"`
+	} `json:"version"`
+	TagLine string `json:"tagline"`
+}
+
+func NewPingService(client *Client) *PingService {
+	return &PingService{
+		client:       client,
+		url:          DefaultURL,
+		httpHeadOnly: false,
+		pretty:       false,
+	}
+}
+
+func (s *PingService) URL(url string) *PingService {
+	s.url = url
+	return s
+}
+
+func (s *PingService) Timeout(timeout string) *PingService {
+	s.timeout = timeout
+	return s
+}
+
+// HeadOnly makes the service to only return the status code in Do;
+// the PingResult will be nil.
+func (s *PingService) HttpHeadOnly(httpHeadOnly bool) *PingService {
+	s.httpHeadOnly = httpHeadOnly
+	return s
+}
+
+func (s *PingService) Pretty(pretty bool) *PingService {
+	s.pretty = pretty
+	return s
+}
+
+// Do returns the PingResult, the HTTP status code of the Elasticsearch
+// server, and an error.
+func (s *PingService) Do() (*PingResult, int, error) {
+	s.client.mu.RLock()
+	basicAuth := s.client.basicAuth
+	basicAuthUsername := s.client.basicAuthUsername
+	basicAuthPassword := s.client.basicAuthPassword
+	s.client.mu.RUnlock()
+
+	url_ := s.url + "/"
+
+	params := make(url.Values)
+	if s.timeout != "" {
+		params.Set("timeout", s.timeout)
+	}
+	if s.pretty {
+		params.Set("pretty", "1")
+	}
+	if len(params) > 0 {
+		url_ += "?" + params.Encode()
+	}
+
+	var method string
+	if s.httpHeadOnly {
+		method = "HEAD"
+	} else {
+		method = "GET"
+	}
+
+	// Notice: This service must NOT use PerformRequest!
+	req, err := NewRequest(method, url_)
+	if err != nil {
+		return nil, 0, err
+	}
+
+	if basicAuth {
+		req.SetBasicAuth(basicAuthUsername, basicAuthPassword)
+	}
+
+	res, err := s.client.c.Do((*http.Request)(req))
+	if err != nil {
+		return nil, 0, err
+	}
+	defer res.Body.Close()
+
+	var ret *PingResult
+	if !s.httpHeadOnly {
+		ret = new(PingResult)
+		if err := json.NewDecoder(res.Body).Decode(ret); err != nil {
+			return nil, res.StatusCode, err
+		}
+	}
+
+	return ret, res.StatusCode, nil
+}