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/msearch.go

@@ -0,0 +1,96 @@
+// 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"
+	"fmt"
+	"net/url"
+	"strings"
+)
+
+// MultiSearch executes one or more searches in one roundtrip.
+// See http://www.elasticsearch.org/guide/reference/api/multi-search/
+type MultiSearchService struct {
+	client     *Client
+	requests   []*SearchRequest
+	indices    []string
+	pretty     bool
+	routing    string
+	preference string
+}
+
+func NewMultiSearchService(client *Client) *MultiSearchService {
+	builder := &MultiSearchService{
+		client:   client,
+		requests: make([]*SearchRequest, 0),
+		indices:  make([]string, 0),
+	}
+	return builder
+}
+
+func (s *MultiSearchService) Add(requests ...*SearchRequest) *MultiSearchService {
+	s.requests = append(s.requests, requests...)
+	return s
+}
+
+func (s *MultiSearchService) Index(indices ...string) *MultiSearchService {
+	s.indices = append(s.indices, indices...)
+	return s
+}
+
+func (s *MultiSearchService) Pretty(pretty bool) *MultiSearchService {
+	s.pretty = pretty
+	return s
+}
+
+func (s *MultiSearchService) Do() (*MultiSearchResult, error) {
+	// Build url
+	path := "/_msearch"
+
+	// Parameters
+	params := make(url.Values)
+	if s.pretty {
+		params.Set("pretty", fmt.Sprintf("%v", s.pretty))
+	}
+
+	// Set body
+	lines := make([]string, 0)
+	for _, sr := range s.requests {
+		// Set default indices if not specified in the request
+		if !sr.HasIndices() && len(s.indices) > 0 {
+			sr = sr.Index(s.indices...)
+		}
+
+		header, err := json.Marshal(sr.header())
+		if err != nil {
+			return nil, err
+		}
+		body, err := json.Marshal(sr.body())
+		if err != nil {
+			return nil, err
+		}
+		lines = append(lines, string(header))
+		lines = append(lines, string(body))
+	}
+	body := strings.Join(lines, "\n") + "\n" // Don't forget trailing \n
+
+	// Get response
+	res, err := s.client.PerformRequest("GET", path, params, body)
+	if err != nil {
+		return nil, err
+	}
+
+	// Return result
+	ret := new(MultiSearchResult)
+	if err := s.client.decoder.Decode(res.Body, ret); err != nil {
+		return nil, err
+	}
+	return ret, nil
+}
+
+type MultiSearchResult struct {
+	Responses []*SearchResult `json:"responses,omitempty"`
+}