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

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/*
* Minio Cloud Storage, (C) 2016, 2017 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"
"fmt"
"io"
"net"
"net/http"
"syscall"
"time"
"github.com/gorilla/mux"
)
const (
bucketConfigPrefix = "buckets"
bucketNotificationConfig = "notification.xml"
bucketListenerConfig = "listener.json"
)
// 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) {
objAPI := api.ObjectAPI()
if objAPI == nil {
writeErrorResponse(w, ErrServerNotInitialized, r.URL)
return
}
if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
writeErrorResponse(w, s3Error, r.URL)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
_, err := objAPI.GetBucketInfo(bucket)
if err != nil {
errorIf(err, "Unable to find bucket info.")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
// Attempt to successfully load notification config.
nConfig, err := loadNotificationConfig(bucket, objAPI)
if err != nil && errorCause(err) != errNoSuchNotifications {
errorIf(err, "Unable to read notification configuration.")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
// For no notifications we write a dummy XML.
if errorCause(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, toAPIErrorCode(err), r.URL)
return
}
// Success.
writeSuccessResponseXML(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) {
objectAPI := api.ObjectAPI()
if objectAPI == nil {
writeErrorResponse(w, ErrServerNotInitialized, r.URL)
return
}
if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
writeErrorResponse(w, s3Error, r.URL)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
_, err := objectAPI.GetBucketInfo(bucket)
if err != nil {
errorIf(err, "Unable to find bucket info.")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
// If Content-Length is unknown or zero, deny the request.
// PutBucketNotification always needs a Content-Length.
if r.ContentLength == -1 || r.ContentLength == 0 {
writeErrorResponse(w, ErrMissingContentLength, r.URL)
return
}
// Reads the incoming notification configuration.
var buffer bytes.Buffer
if r.ContentLength >= 0 {
_, err = io.CopyN(&buffer, r.Body, r.ContentLength)
} else {
_, err = io.Copy(&buffer, r.Body)
}
if err != nil {
errorIf(err, "Unable to read incoming body.")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
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, ErrMalformedXML, r.URL)
return
} // Successfully marshalled notification configuration.
// Validate unmarshalled bucket notification configuration.
if s3Error := validateNotificationConfig(notificationCfg); s3Error != ErrNone {
writeErrorResponse(w, s3Error, r.URL)
return
}
// Convert the incoming ARNs properly to the GetRegion().
for i, queueConfig := range notificationCfg.QueueConfigs {
queueConfig.QueueARN = unmarshalSqsARN(queueConfig.QueueARN).String()
notificationCfg.QueueConfigs[i] = queueConfig
}
// Put bucket notification config.
err = PutBucketNotificationConfig(bucket, &notificationCfg, objectAPI)
if err != nil {
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
// Success.
writeSuccessResponseHeadersOnly(w)
}
// PutBucketNotificationConfig - Put a new notification config for a
// bucket (overwrites any previous config) persistently, updates
// global in-memory state, and notify other nodes in the cluster (if
// any)
func PutBucketNotificationConfig(bucket string, ncfg *notificationConfig, objAPI ObjectLayer) error {
if ncfg == nil {
return errInvalidArgument
}
// Acquire a write lock on bucket before modifying its
// configuration.
bucketLock := globalNSMutex.NewNSLock(bucket, "")
if err := bucketLock.GetLock(globalOperationTimeout); err != nil {
return err
}
// Release lock after notifying peers
defer bucketLock.Unlock()
// persist config to disk
err := persistNotificationConfig(bucket, ncfg, objAPI)
if err != nil {
return fmt.Errorf("Unable to persist Bucket notification config to object layer - config=%v errMsg=%v", *ncfg, err)
}
// All servers (including local) are told to update in-memory config
S3PeersUpdateBucketNotification(bucket, ncfg)
return 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 JSON 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()
return err
}
// CRLF character used for chunked transfer in accordance with HTTP standards.
var crlf = []byte("\r\n")
// listenChan A `listenChan` provides a data channel to send event
// notifications on and `doneCh` to signal that events are no longer
// being received. It also sends empty events (whitespace) to keep the
// underlying connection alive.
type listenChan struct {
doneCh chan struct{}
dataCh chan []NotificationEvent
}
// newListenChan returns a listenChan with properly initialized
// unbuffered channels.
func newListenChan() *listenChan {
return &listenChan{
doneCh: make(chan struct{}),
dataCh: make(chan []NotificationEvent),
}
}
// sendNotificationEvent sends notification events on the data channel
// unless doneCh is not closed
func (l *listenChan) sendNotificationEvent(events []NotificationEvent) {
select {
// Returns immediately if receiver has quit.
case <-l.doneCh:
// Blocks until receiver is available.
case l.dataCh <- events:
}
}
// waitForListener writes event notification OR whitespaces on
// ResponseWriter until client closes connection
func (l *listenChan) waitForListener(w http.ResponseWriter) {
// Logs errors other than EPIPE and ECONNRESET.
// EPIPE and ECONNRESET indicate that the client stopped
// listening to notification events.
logClientError := func(err error, msg string) {
if oe, ok := err.(*net.OpError); ok && (oe.Err == syscall.EPIPE || oe.Err ==
syscall.ECONNRESET) {
errorIf(err, msg)
}
}
emptyEvent := map[string][]NotificationEvent{"Records": nil}
defer close(l.doneCh)
for {
select {
case events := <-l.dataCh:
if err := writeNotification(w, map[string][]NotificationEvent{"Records": events}); err != nil {
logClientError(err, "Unable to write notification")
return
}
case <-time.After(globalSNSConnAlive):
if err := writeNotification(w, emptyEvent); err != nil {
logClientError(err, "Unable to write empty notification")
return
}
}
}
}
// ListenBucketNotificationHandler - list bucket notifications.
func (api objectAPIHandlers) ListenBucketNotificationHandler(w http.ResponseWriter, r *http.Request) {
// Validate if bucket exists.
objAPI := api.ObjectAPI()
if objAPI == nil {
writeErrorResponse(w, ErrServerNotInitialized, r.URL)
return
}
if s3Error := checkRequestAuthType(r, "", "", serverConfig.GetRegion()); s3Error != ErrNone {
writeErrorResponse(w, s3Error, r.URL)
return
}
vars := mux.Vars(r)
bucket := vars["bucket"]
// Parse listen bucket notification resources.
prefixes, suffixes, events := getListenBucketNotificationResources(r.URL.Query())
if err := validateFilterValues(prefixes); err != ErrNone {
writeErrorResponse(w, err, r.URL)
return
}
if err := validateFilterValues(suffixes); err != ErrNone {
writeErrorResponse(w, err, r.URL)
return
}
// Validate all the resource events.
for _, event := range events {
if errCode := checkEvent(event); errCode != ErrNone {
writeErrorResponse(w, errCode, r.URL)
return
}
}
_, err := objAPI.GetBucketInfo(bucket)
if err != nil {
errorIf(err, "Unable to get bucket info.")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
targetServer := GetLocalPeer(globalEndpoints)
accountID := fmt.Sprintf("%d", UTCNow().UnixNano())
accountARN := fmt.Sprintf(
"%s:%s:%s:%s-%s",
minioTopic,
serverConfig.GetRegion(),
accountID,
snsTypeMinio,
targetServer,
)
var filterRules []filterRule
for _, prefix := range prefixes {
filterRules = append(filterRules, filterRule{
Name: "prefix",
Value: prefix,
})
}
for _, suffix := range suffixes {
filterRules = append(filterRules, filterRule{
Name: "suffix",
Value: suffix,
})
}
// Make topic configuration corresponding to this
// ListenBucketNotification request.
topicCfg := &topicConfig{
TopicARN: accountARN,
ServiceConfig: ServiceConfig{
Events: events,
Filter: struct {
Key keyFilter `xml:"S3Key,omitempty" json:"S3Key,omitempty"`
}{
Key: keyFilter{
FilterRules: filterRules,
},
},
ID: "sns-" + accountID,
},
}
// Setup a listen channel to receive notifications like
// s3:ObjectCreated, s3:ObjectDeleted etc.
nListenCh := newListenChan()
// Add channel for listener events
if err = globalEventNotifier.AddListenerChan(accountARN, nListenCh); err != nil {
errorIf(err, "Error adding a listener!")
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
// Remove listener channel after the writer has closed or the
// client disconnected.
defer globalEventNotifier.RemoveListenerChan(accountARN)
// Update topic config to bucket config and persist - as soon
// as this call completes, events may start appearing in
// nListenCh
lc := listenerConfig{
TopicConfig: *topicCfg,
TargetServer: targetServer,
}
err = AddBucketListenerConfig(bucket, &lc, objAPI)
if err != nil {
writeErrorResponse(w, toAPIErrorCode(err), r.URL)
return
}
defer RemoveBucketListenerConfig(bucket, &lc, objAPI)
// Add all common headers.
setCommonHeaders(w)
// https://github.com/containous/traefik/issues/560
// https://developer.mozilla.org/en-US/docs/Web/API/Server-sent_events/Using_server-sent_events
//
// Proxies might buffer the connection to avoid this we
// need the proper MIME type before writing to client.
// This MIME header tells the proxies to avoid buffering
w.Header().Set("Content-Type", "text/event-stream")
// Start writing bucket notifications to ResponseWriter.
nListenCh.waitForListener(w)
}
// AddBucketListenerConfig - Updates on disk state of listeners, and
// updates all peers with the change in listener config.
func AddBucketListenerConfig(bucket string, lcfg *listenerConfig, objAPI ObjectLayer) error {
if lcfg == nil {
return errInvalidArgument
}
listenerCfgs := globalEventNotifier.GetBucketListenerConfig(bucket)
// add new lid to listeners and persist to object layer.
listenerCfgs = append(listenerCfgs, *lcfg)
// Acquire a write lock on bucket before modifying its
// configuration.
bucketLock := globalNSMutex.NewNSLock(bucket, "")
if err := bucketLock.GetLock(globalOperationTimeout); err != nil {
return err
}
// Release lock after notifying peers
defer bucketLock.Unlock()
// update persistent config if dist XL
if globalIsDistXL {
err := persistListenerConfig(bucket, listenerCfgs, objAPI)
if err != nil {
errorIf(err, "Error persisting listener config when adding a listener.")
return err
}
}
// persistence success - now update in-memory globals on all
// peers (including local)
S3PeersUpdateBucketListener(bucket, listenerCfgs)
return nil
}
// RemoveBucketListenerConfig - removes a given bucket notification config
func RemoveBucketListenerConfig(bucket string, lcfg *listenerConfig, objAPI ObjectLayer) {
listenerCfgs := globalEventNotifier.GetBucketListenerConfig(bucket)
// remove listener with matching ARN - if not found ignore and exit.
var updatedLcfgs []listenerConfig
found := false
for k, configuredLcfg := range listenerCfgs {
if configuredLcfg.TopicConfig.TopicARN == lcfg.TopicConfig.TopicARN {
updatedLcfgs = append(listenerCfgs[:k],
listenerCfgs[k+1:]...)
found = true
break
}
}
if !found {
return
}
// Acquire a write lock on bucket before modifying its
// configuration.
bucketLock := globalNSMutex.NewNSLock(bucket, "")
if bucketLock.GetLock(globalOperationTimeout) != nil {
return
}
// Release lock after notifying peers
defer bucketLock.Unlock()
// update persistent config if dist XL
if globalIsDistXL {
err := persistListenerConfig(bucket, updatedLcfgs, objAPI)
if err != nil {
errorIf(err, "Error persisting listener config when removing a listener.")
return
}
}
// persistence success - now update in-memory globals on all
// peers (including local)
S3PeersUpdateBucketListener(bucket, updatedLcfgs)
}