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/rescorer.go

@@ -0,0 +1,64 @@
+// 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
+
+type Rescorer interface {
+	Name() string
+	Source() (interface{}, error)
+}
+
+// -- Query Rescorer --
+
+type QueryRescorer struct {
+	query              Query
+	rescoreQueryWeight *float64
+	queryWeight        *float64
+	scoreMode          string
+}
+
+func NewQueryRescorer(query Query) *QueryRescorer {
+	return &QueryRescorer{
+		query: query,
+	}
+}
+
+func (r *QueryRescorer) Name() string {
+	return "query"
+}
+
+func (r *QueryRescorer) RescoreQueryWeight(rescoreQueryWeight float64) *QueryRescorer {
+	r.rescoreQueryWeight = &rescoreQueryWeight
+	return r
+}
+
+func (r *QueryRescorer) QueryWeight(queryWeight float64) *QueryRescorer {
+	r.queryWeight = &queryWeight
+	return r
+}
+
+func (r *QueryRescorer) ScoreMode(scoreMode string) *QueryRescorer {
+	r.scoreMode = scoreMode
+	return r
+}
+
+func (r *QueryRescorer) Source() (interface{}, error) {
+	rescoreQuery, err := r.query.Source()
+	if err != nil {
+		return nil, err
+	}
+
+	source := make(map[string]interface{})
+	source["rescore_query"] = rescoreQuery
+	if r.queryWeight != nil {
+		source["query_weight"] = *r.queryWeight
+	}
+	if r.rescoreQueryWeight != nil {
+		source["rescore_query_weight"] = *r.rescoreQueryWeight
+	}
+	if r.scoreMode != "" {
+		source["score_mode"] = r.scoreMode
+	}
+	return source, nil
+}