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/search_queries_terms.go

@@ -0,0 +1,58 @@
+// 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
+
+// TermsQuery filters documents that have fields that match any
+// of the provided terms (not analyzed).
+//
+// For more details, see
+// https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-terms-query.html
+type TermsQuery struct {
+	name      string
+	values    []interface{}
+	queryName string
+	boost     *float64
+}
+
+// NewTermsQuery creates and initializes a new TermsQuery.
+func NewTermsQuery(name string, values ...interface{}) *TermsQuery {
+	q := &TermsQuery{
+		name:   name,
+		values: make([]interface{}, 0),
+	}
+	if len(values) > 0 {
+		q.values = append(q.values, values...)
+	}
+	return q
+}
+
+// Boost sets the boost for this query.
+func (q *TermsQuery) Boost(boost float64) *TermsQuery {
+	q.boost = &boost
+	return q
+}
+
+// QueryName sets the query name for the filter that can be used
+// when searching for matched_filters per hit
+func (q *TermsQuery) QueryName(queryName string) *TermsQuery {
+	q.queryName = queryName
+	return q
+}
+
+// Creates the query source for the term query.
+func (q *TermsQuery) Source() (interface{}, error) {
+	// {"terms":{"name":["value1","value2"]}}
+	source := make(map[string]interface{})
+	params := make(map[string]interface{})
+	source["terms"] = params
+	params[q.name] = q.values
+	if q.boost != nil {
+		params["boost"] = *q.boost
+	}
+	if q.queryName != "" {
+		params["_name"] = q.queryName
+	}
+	return source, nil
+}