syncthing/vendor/github.com/minio/minio-go/api-notification.go
Jakob Borg 916ec63af6 cmd/stdiscosrv: New discovery server (fixes #4618)
This is a new revision of the discovery server. Relevant changes and
non-changes:

- Protocol towards clients is unchanged.

- Recommended large scale design is still to be deployed nehind nginx (I
  tested, and it's still a lot faster at terminating TLS).

- Database backend is leveldb again, only. It scales enough, is easy to
  setup, and we don't need any backend to take care of.

- Server supports replication. This is a simple TCP channel - protect it
  with a firewall when deploying over the internet. (We deploy this within
  the same datacenter, and with firewall.) Any incoming client announces
  are sent over the replication channel(s) to other peer discosrvs.
  Incoming replication changes are applied to the database as if they came
  from clients, but without the TLS/certificate overhead.

- Metrics are exposed using the prometheus library, when enabled.

- The database values and replication protocol is protobuf, because JSON
  was quite CPU intensive when I tried that and benchmarked it.

- The "Retry-After" value for failed lookups gets slowly increased from
  a default of 120 seconds, by 5 seconds for each failed lookup,
  independently by each discosrv. This lowers the query load over time for
  clients that are never seen. The Retry-After maxes out at 3600 after a
  couple of weeks of this increase. The number of failed lookups is
  stored in the database, now and then (avoiding making each lookup a
  database put).

All in all this means clients can be pointed towards a cluster using
just multiple A / AAAA records to gain both load sharing and redundancy
(if one is down, clients will talk to the remaining ones).

GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
2018-01-14 08:52:31 +00:00

231 lines
7.1 KiB
Go

/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 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 minio
import (
"bufio"
"context"
"encoding/json"
"io"
"net/http"
"net/url"
"time"
"github.com/minio/minio-go/pkg/s3utils"
)
// GetBucketNotification - get bucket notification at a given path.
func (c Client) GetBucketNotification(bucketName string) (bucketNotification BucketNotification, err error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return BucketNotification{}, err
}
notification, err := c.getBucketNotification(bucketName)
if err != nil {
return BucketNotification{}, err
}
return notification, nil
}
// Request server for notification rules.
func (c Client) getBucketNotification(bucketName string) (BucketNotification, error) {
urlValues := make(url.Values)
urlValues.Set("notification", "")
// Execute GET on bucket to list objects.
resp, err := c.executeMethod(context.Background(), "GET", requestMetadata{
bucketName: bucketName,
queryValues: urlValues,
contentSHA256Hex: emptySHA256Hex,
})
defer closeResponse(resp)
if err != nil {
return BucketNotification{}, err
}
return processBucketNotificationResponse(bucketName, resp)
}
// processes the GetNotification http response from the server.
func processBucketNotificationResponse(bucketName string, resp *http.Response) (BucketNotification, error) {
if resp.StatusCode != http.StatusOK {
errResponse := httpRespToErrorResponse(resp, bucketName, "")
return BucketNotification{}, errResponse
}
var bucketNotification BucketNotification
err := xmlDecoder(resp.Body, &bucketNotification)
if err != nil {
return BucketNotification{}, err
}
return bucketNotification, nil
}
// Indentity represents the user id, this is a compliance field.
type identity struct {
PrincipalID string `json:"principalId"`
}
// Notification event bucket metadata.
type bucketMeta struct {
Name string `json:"name"`
OwnerIdentity identity `json:"ownerIdentity"`
ARN string `json:"arn"`
}
// Notification event object metadata.
type objectMeta struct {
Key string `json:"key"`
Size int64 `json:"size,omitempty"`
ETag string `json:"eTag,omitempty"`
VersionID string `json:"versionId,omitempty"`
Sequencer string `json:"sequencer"`
}
// Notification event server specific metadata.
type eventMeta struct {
SchemaVersion string `json:"s3SchemaVersion"`
ConfigurationID string `json:"configurationId"`
Bucket bucketMeta `json:"bucket"`
Object objectMeta `json:"object"`
}
// sourceInfo represents information on the client that
// triggered the event notification.
type sourceInfo struct {
Host string `json:"host"`
Port string `json:"port"`
UserAgent string `json:"userAgent"`
}
// NotificationEvent represents an Amazon an S3 bucket notification event.
type NotificationEvent struct {
EventVersion string `json:"eventVersion"`
EventSource string `json:"eventSource"`
AwsRegion string `json:"awsRegion"`
EventTime string `json:"eventTime"`
EventName string `json:"eventName"`
UserIdentity identity `json:"userIdentity"`
RequestParameters map[string]string `json:"requestParameters"`
ResponseElements map[string]string `json:"responseElements"`
S3 eventMeta `json:"s3"`
Source sourceInfo `json:"source"`
}
// NotificationInfo - represents the collection of notification events, additionally
// also reports errors if any while listening on bucket notifications.
type NotificationInfo struct {
Records []NotificationEvent
Err error
}
// ListenBucketNotification - listen on bucket notifications.
func (c Client) ListenBucketNotification(bucketName, prefix, suffix string, events []string, doneCh <-chan struct{}) <-chan NotificationInfo {
notificationInfoCh := make(chan NotificationInfo, 1)
// Only success, start a routine to start reading line by line.
go func(notificationInfoCh chan<- NotificationInfo) {
defer close(notificationInfoCh)
// Validate the bucket name.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
notificationInfoCh <- NotificationInfo{
Err: err,
}
return
}
// Check ARN partition to verify if listening bucket is supported
if s3utils.IsAmazonEndpoint(c.endpointURL) || s3utils.IsGoogleEndpoint(c.endpointURL) {
notificationInfoCh <- NotificationInfo{
Err: ErrAPINotSupported("Listening for bucket notification is specific only to `minio` server endpoints"),
}
return
}
// Continuously run and listen on bucket notification.
// Create a done channel to control 'ListObjects' go routine.
retryDoneCh := make(chan struct{}, 1)
// Indicate to our routine to exit cleanly upon return.
defer close(retryDoneCh)
// Wait on the jitter retry loop.
for range c.newRetryTimerContinous(time.Second, time.Second*30, MaxJitter, retryDoneCh) {
urlValues := make(url.Values)
urlValues.Set("prefix", prefix)
urlValues.Set("suffix", suffix)
urlValues["events"] = events
// Execute GET on bucket to list objects.
resp, err := c.executeMethod(context.Background(), "GET", requestMetadata{
bucketName: bucketName,
queryValues: urlValues,
contentSHA256Hex: emptySHA256Hex,
})
if err != nil {
notificationInfoCh <- NotificationInfo{
Err: err,
}
return
}
// Validate http response, upon error return quickly.
if resp.StatusCode != http.StatusOK {
errResponse := httpRespToErrorResponse(resp, bucketName, "")
notificationInfoCh <- NotificationInfo{
Err: errResponse,
}
return
}
// Initialize a new bufio scanner, to read line by line.
bio := bufio.NewScanner(resp.Body)
// Close the response body.
defer resp.Body.Close()
// Unmarshal each line, returns marshalled values.
for bio.Scan() {
var notificationInfo NotificationInfo
if err = json.Unmarshal(bio.Bytes(), &notificationInfo); err != nil {
continue
}
// Send notifications on channel only if there are events received.
if len(notificationInfo.Records) > 0 {
select {
case notificationInfoCh <- notificationInfo:
case <-doneCh:
return
}
}
}
// Look for any underlying errors.
if err = bio.Err(); err != nil {
// For an unexpected connection drop from server, we close the body
// and re-connect.
if err == io.ErrUnexpectedEOF {
resp.Body.Close()
}
}
}
}(notificationInfoCh)
// Returns the notification info channel, for caller to start reading from.
return notificationInfoCh
}