syncthing/vendor/github.com/minio/minio-go/api-stat.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

179 lines
5.2 KiB
Go

/*
* Minio Go Library for Amazon S3 Compatible Cloud Storage
* Copyright 2015-2017 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 (
"context"
"net/http"
"strconv"
"strings"
"time"
"github.com/minio/minio-go/pkg/s3utils"
)
// BucketExists verify if bucket exists and you have permission to access it.
func (c Client) BucketExists(bucketName string) (bool, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return false, err
}
// Execute HEAD on bucketName.
resp, err := c.executeMethod(context.Background(), "HEAD", requestMetadata{
bucketName: bucketName,
contentSHA256Hex: emptySHA256Hex,
})
defer closeResponse(resp)
if err != nil {
if ToErrorResponse(err).Code == "NoSuchBucket" {
return false, nil
}
return false, err
}
if resp != nil {
if resp.StatusCode != http.StatusOK {
return false, httpRespToErrorResponse(resp, bucketName, "")
}
}
return true, nil
}
// List of header keys to be filtered, usually
// from all S3 API http responses.
var defaultFilterKeys = []string{
"Connection",
"Transfer-Encoding",
"Accept-Ranges",
"Date",
"Server",
"Vary",
"x-amz-bucket-region",
"x-amz-request-id",
"x-amz-id-2",
// Add new headers to be ignored.
}
// Extract only necessary metadata header key/values by
// filtering them out with a list of custom header keys.
func extractObjMetadata(header http.Header) http.Header {
filterKeys := append([]string{
"ETag",
"Content-Length",
"Last-Modified",
"Content-Type",
}, defaultFilterKeys...)
return filterHeader(header, filterKeys)
}
// StatObject verifies if object exists and you have permission to access.
func (c Client) StatObject(bucketName, objectName string, opts StatObjectOptions) (ObjectInfo, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return ObjectInfo{}, err
}
if err := s3utils.CheckValidObjectName(objectName); err != nil {
return ObjectInfo{}, err
}
return c.statObject(context.Background(), bucketName, objectName, opts)
}
// Lower level API for statObject supporting pre-conditions and range headers.
func (c Client) statObject(ctx context.Context, bucketName, objectName string, opts StatObjectOptions) (ObjectInfo, error) {
// Input validation.
if err := s3utils.CheckValidBucketName(bucketName); err != nil {
return ObjectInfo{}, err
}
if err := s3utils.CheckValidObjectName(objectName); err != nil {
return ObjectInfo{}, err
}
// Execute HEAD on objectName.
resp, err := c.executeMethod(ctx, "HEAD", requestMetadata{
bucketName: bucketName,
objectName: objectName,
contentSHA256Hex: emptySHA256Hex,
customHeader: opts.Header(),
})
defer closeResponse(resp)
if err != nil {
return ObjectInfo{}, err
}
if resp != nil {
if resp.StatusCode != http.StatusOK {
return ObjectInfo{}, httpRespToErrorResponse(resp, bucketName, objectName)
}
}
// Trim off the odd double quotes from ETag in the beginning and end.
md5sum := strings.TrimPrefix(resp.Header.Get("ETag"), "\"")
md5sum = strings.TrimSuffix(md5sum, "\"")
// Parse content length is exists
var size int64 = -1
contentLengthStr := resp.Header.Get("Content-Length")
if contentLengthStr != "" {
size, err = strconv.ParseInt(contentLengthStr, 10, 64)
if err != nil {
// Content-Length is not valid
return ObjectInfo{}, ErrorResponse{
Code: "InternalError",
Message: "Content-Length is invalid. " + reportIssue,
BucketName: bucketName,
Key: objectName,
RequestID: resp.Header.Get("x-amz-request-id"),
HostID: resp.Header.Get("x-amz-id-2"),
Region: resp.Header.Get("x-amz-bucket-region"),
}
}
}
// Parse Last-Modified has http time format.
date, err := time.Parse(http.TimeFormat, resp.Header.Get("Last-Modified"))
if err != nil {
return ObjectInfo{}, ErrorResponse{
Code: "InternalError",
Message: "Last-Modified time format is invalid. " + reportIssue,
BucketName: bucketName,
Key: objectName,
RequestID: resp.Header.Get("x-amz-request-id"),
HostID: resp.Header.Get("x-amz-id-2"),
Region: resp.Header.Get("x-amz-bucket-region"),
}
}
// Fetch content type if any present.
contentType := strings.TrimSpace(resp.Header.Get("Content-Type"))
if contentType == "" {
contentType = "application/octet-stream"
}
// Save object metadata info.
return ObjectInfo{
ETag: md5sum,
Key: objectName,
Size: size,
LastModified: date,
ContentType: contentType,
// Extract only the relevant header keys describing the object.
// following function filters out a list of standard set of keys
// which are not part of object metadata.
Metadata: extractObjMetadata(resp.Header),
}, nil
}