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_script.go

@@ -0,0 +1,51 @@
+// 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 "errors"
+
+// ScriptQuery allows to define scripts as filters.
+//
+// For details, see
+// https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-script-query.html
+type ScriptQuery struct {
+	script    *Script
+	queryName string
+}
+
+// NewScriptQuery creates and initializes a new ScriptQuery.
+func NewScriptQuery(script *Script) *ScriptQuery {
+	return &ScriptQuery{
+		script: script,
+	}
+}
+
+// QueryName sets the query name for the filter that can be used
+// when searching for matched_filters per hit
+func (q *ScriptQuery) QueryName(queryName string) *ScriptQuery {
+	q.queryName = queryName
+	return q
+}
+
+// Source returns JSON for the query.
+func (q *ScriptQuery) Source() (interface{}, error) {
+	if q.script == nil {
+		return nil, errors.New("ScriptQuery expected a script")
+	}
+	source := make(map[string]interface{})
+	params := make(map[string]interface{})
+	source["script"] = params
+
+	src, err := q.script.Source()
+	if err != nil {
+		return nil, err
+	}
+	params["script"] = src
+
+	if q.queryName != "" {
+		params["_name"] = q.queryName
+	}
+	return source, nil
+}