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/geo_point.go

@@ -0,0 +1,48 @@
+// 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 (
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+// GeoPoint is a geographic position described via latitude and longitude.
+type GeoPoint struct {
+	Lat float64 `json:"lat"`
+	Lon float64 `json:"lon"`
+}
+
+// Source returns the object to be serialized in Elasticsearch DSL.
+func (pt *GeoPoint) Source() map[string]float64 {
+	return map[string]float64{
+		"lat": pt.Lat,
+		"lon": pt.Lon,
+	}
+}
+
+// GeoPointFromLatLon initializes a new GeoPoint by latitude and longitude.
+func GeoPointFromLatLon(lat, lon float64) *GeoPoint {
+	return &GeoPoint{Lat: lat, Lon: lon}
+}
+
+// GeoPointFromString initializes a new GeoPoint by a string that is
+// formatted as "{latitude},{longitude}", e.g. "40.10210,-70.12091".
+func GeoPointFromString(latLon string) (*GeoPoint, error) {
+	latlon := strings.SplitN(latLon, ",", 2)
+	if len(latlon) != 2 {
+		return nil, fmt.Errorf("elastic: %s is not a valid geo point string", latLon)
+	}
+	lat, err := strconv.ParseFloat(latlon[0], 64)
+	if err != nil {
+		return nil, err
+	}
+	lon, err := strconv.ParseFloat(latlon[1], 64)
+	if err != nil {
+		return nil, err
+	}
+	return &GeoPoint{Lat: lat, Lon: lon}, nil
+}