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minio/cmd/bucket-notification-handler...

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/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package cmd
import (
"bytes"
"encoding/json"
"encoding/xml"
"io"
"net/http"
"path"
"time"
"github.com/gorilla/mux"
)
const (
bucketConfigPrefix = "buckets"
bucketNotificationConfig = "notification.xml"
)
// GetBucketNotificationHandler - This implementation of the GET
// operation uses the notification subresource to return the
// notification configuration of a bucket. If notifications are
// not enabled on the bucket, the operation returns an empty
// NotificationConfiguration element.
func (api objectAPIHandlers) GetBucketNotificationHandler(w http.ResponseWriter, r *http.Request) {
// Validate request authorization.
if s3Error := checkAuth(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
// Attempt to successfully load notification config.
nConfig, err := loadNotificationConfig(bucket, api.ObjectAPI)
if err != nil && err != errNoSuchNotifications {
errorIf(err, "Unable to read notification configuration.")
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
// For no notifications we write a dummy XML.
if err == errNoSuchNotifications {
// Complies with the s3 behavior in this regard.
nConfig = &notificationConfig{}
}
notificationBytes, err := xml.Marshal(nConfig)
if err != nil {
// For any marshalling failure.
errorIf(err, "Unable to marshal notification configuration into XML.", err)
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
// Success.
writeSuccessResponse(w, notificationBytes)
}
// PutBucketNotificationHandler - Minio notification feature enables
// you to receive notifications when certain events happen in your bucket.
// Using this API, you can replace an existing notification configuration.
// The configuration is an XML file that defines the event types that you
// want Minio to publish and the destination where you want Minio to publish
// an event notification when it detects an event of the specified type.
// By default, your bucket has no event notifications configured. That is,
// the notification configuration will be an empty NotificationConfiguration.
func (api objectAPIHandlers) PutBucketNotificationHandler(w http.ResponseWriter, r *http.Request) {
// Validate request authorization.
if s3Error := checkAuth(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
_, err := api.ObjectAPI.GetBucketInfo(bucket)
if err != nil {
errorIf(err, "Unable to find bucket info.")
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
// If Content-Length is unknown or zero, deny the request. PutBucketNotification
// always needs a Content-Length if incoming request is not chunked.
if !contains(r.TransferEncoding, "chunked") {
if r.ContentLength == -1 {
writeErrorResponse(w, r, ErrMissingContentLength, r.URL.Path)
return
}
}
// Reads the incoming notification configuration.
var buffer bytes.Buffer
var bufferSize int64
if r.ContentLength >= 0 {
bufferSize, err = io.CopyN(&buffer, r.Body, r.ContentLength)
} else {
bufferSize, err = io.Copy(&buffer, r.Body)
}
if err != nil {
errorIf(err, "Unable to read incoming body.")
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
var notificationCfg notificationConfig
// Unmarshal notification bytes.
notificationConfigBytes := buffer.Bytes()
if err = xml.Unmarshal(notificationConfigBytes, &notificationCfg); err != nil {
errorIf(err, "Unable to parse notification configuration XML.")
writeErrorResponse(w, r, ErrMalformedXML, r.URL.Path)
return
} // Successfully marshalled notification configuration.
// Validate unmarshalled bucket notification configuration.
if s3Error := validateNotificationConfig(notificationCfg); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
// Proceed to save notification configuration.
notificationConfigPath := path.Join(bucketConfigPrefix, bucket, bucketNotificationConfig)
_, err = api.ObjectAPI.PutObject(minioMetaBucket, notificationConfigPath, bufferSize, bytes.NewReader(buffer.Bytes()), nil)
if err != nil {
errorIf(err, "Unable to write bucket notification configuration.")
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
// Set bucket notification config.
eventN.SetBucketNotificationConfig(bucket, &notificationCfg)
// Success.
writeSuccessResponse(w, nil)
}
// writeNotification marshals notification message before writing to client.
func writeNotification(w http.ResponseWriter, notification map[string][]NotificationEvent) error {
// Invalid response writer.
if w == nil {
return errInvalidArgument
}
// Invalid notification input.
if notification == nil {
return errInvalidArgument
}
// Marshal notification data into XML and write to client.
notificationBytes, err := json.Marshal(&notification)
if err != nil {
return err
}
// Add additional CRLF characters for client to
// differentiate the individual events properly.
_, err = w.Write(append(notificationBytes, crlf...))
// Make sure we have flushed, this would set Transfer-Encoding: chunked.
w.(http.Flusher).Flush()
if err != nil {
return err
}
return nil
}
// CRLF character used for chunked transfer in accordance with HTTP standards.
var crlf = []byte("\r\n")
// sendBucketNotification - writes notification back to client on the response writer
// for each notification input, otherwise writes whitespace characters periodically
// to keep the connection active. Each notification messages are terminated by CRLF
// character. Upon any error received on response writer the for loop exits.
//
// TODO - do not log for all errors.
func sendBucketNotification(w http.ResponseWriter, arnListenerCh <-chan []NotificationEvent) {
var dummyEvents = map[string][]NotificationEvent{"Records": nil}
// Continuously write to client either timely empty structures
// every 5 seconds, or return back the notifications.
for {
select {
case events := <-arnListenerCh:
if err := writeNotification(w, map[string][]NotificationEvent{"Records": events}); err != nil {
errorIf(err, "Unable to write notification to client.")
return
}
case <-time.After(5 * time.Second):
if err := writeNotification(w, dummyEvents); err != nil {
errorIf(err, "Unable to write notification to client.")
return
}
}
}
}
// ListenBucketNotificationHandler - list bucket notifications.
func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWriter, r *http.Request) {
// Validate request authorization.
if s3Error := checkAuth(r); s3Error != ErrNone {
writeErrorResponse(w, r, s3Error, r.URL.Path)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
// Get notification ARN.
topicARN := r.URL.Query().Get("notificationARN")
if topicARN == "" {
writeErrorResponse(w, r, ErrARNNotification, r.URL.Path)
return
}
// Validate if bucket exists.
_, err := api.ObjectAPI.GetBucketInfo(bucket)
if err != nil {
errorIf(err, "Unable to bucket info.")
writeErrorResponse(w, r, toAPIErrorCode(err), r.URL.Path)
return
}
notificationCfg := eventN.GetBucketNotificationConfig(bucket)
if notificationCfg == nil {
writeErrorResponse(w, r, ErrARNNotification, r.URL.Path)
return
}
// Set SNS notifications only if special "listen" sns is set in bucket
// notification configs.
if !isMinioSNSConfigured(topicARN, notificationCfg.TopicConfigs) {
writeErrorResponse(w, r, ErrARNNotification, r.URL.Path)
return
}
// Add all common headers.
setCommonHeaders(w)
// Create a new notification event channel.
nEventCh := make(chan []NotificationEvent)
// Close the listener channel.
defer close(nEventCh)
// Set sns target.
eventN.SetSNSTarget(topicARN, nEventCh)
// Remove sns listener after the writer has closed or the client disconnected.
defer eventN.RemoveSNSTarget(topicARN, nEventCh)
// Start sending bucket notifications.
sendBucketNotification(w, nEventCh)
}
// Removes notification.xml for a given bucket, only used during DeleteBucket.
func removeNotificationConfig(bucket string, objAPI ObjectLayer) error {
// Verify bucket is valid.
if !IsValidBucketName(bucket) {
return BucketNameInvalid{Bucket: bucket}
}
notificationConfigPath := path.Join(bucketConfigPrefix, bucket, bucketNotificationConfig)
return objAPI.DeleteObject(minioMetaBucket, notificationConfigPath)
}