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/indices_exists_template.go

@@ -0,0 +1,112 @@
+// 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"
+	"net/http"
+	"net/url"
+
+	"gopkg.in/olivere/elastic.v3/uritemplates"
+)
+
+// IndicesExistsTemplateService checks if a given template exists.
+// See http://www.elastic.co/guide/en/elasticsearch/reference/current/indices-templates.html#indices-templates-exists
+// for documentation.
+type IndicesExistsTemplateService struct {
+	client *Client
+	pretty bool
+	name   string
+	local  *bool
+}
+
+// NewIndicesExistsTemplateService creates a new IndicesExistsTemplateService.
+func NewIndicesExistsTemplateService(client *Client) *IndicesExistsTemplateService {
+	return &IndicesExistsTemplateService{
+		client: client,
+	}
+}
+
+// Name is the name of the template.
+func (s *IndicesExistsTemplateService) Name(name string) *IndicesExistsTemplateService {
+	s.name = name
+	return s
+}
+
+// Local indicates whether to return local information, i.e. do not retrieve
+// the state from master node (default: false).
+func (s *IndicesExistsTemplateService) Local(local bool) *IndicesExistsTemplateService {
+	s.local = &local
+	return s
+}
+
+// Pretty indicates that the JSON response be indented and human readable.
+func (s *IndicesExistsTemplateService) Pretty(pretty bool) *IndicesExistsTemplateService {
+	s.pretty = pretty
+	return s
+}
+
+// buildURL builds the URL for the operation.
+func (s *IndicesExistsTemplateService) buildURL() (string, url.Values, error) {
+	// Build URL
+	path, err := uritemplates.Expand("/_template/{name}", map[string]string{
+		"name": s.name,
+	})
+	if err != nil {
+		return "", url.Values{}, err
+	}
+
+	// Add query string parameters
+	params := url.Values{}
+	if s.pretty {
+		params.Set("pretty", "1")
+	}
+	if s.local != nil {
+		params.Set("local", fmt.Sprintf("%v", *s.local))
+	}
+	return path, params, nil
+}
+
+// Validate checks if the operation is valid.
+func (s *IndicesExistsTemplateService) Validate() error {
+	var invalid []string
+	if s.name == "" {
+		invalid = append(invalid, "Name")
+	}
+	if len(invalid) > 0 {
+		return fmt.Errorf("missing required fields: %v", invalid)
+	}
+	return nil
+}
+
+// Do executes the operation.
+func (s *IndicesExistsTemplateService) Do() (bool, error) {
+	// Check pre-conditions
+	if err := s.Validate(); err != nil {
+		return false, err
+	}
+
+	// Get URL for request
+	path, params, err := s.buildURL()
+	if err != nil {
+		return false, err
+	}
+
+	// Get HTTP response
+	res, err := s.client.PerformRequest("HEAD", path, params, nil, 404)
+	if err != nil {
+		return false, err
+	}
+
+	// Return operation response
+	switch res.StatusCode {
+	case http.StatusOK:
+		return true, nil
+	case http.StatusNotFound:
+		return false, nil
+	default:
+		return false, fmt.Errorf("elastic: got HTTP code %d when it should have been either 200 or 404", res.StatusCode)
+	}
+}