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Modify backup process to utilize contexts and exponential backoffs

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If a request to upload a file part to S3 fails for any 5xx reason it will begin using an exponential backoff to keep re-trying the upload until we've reached a minute of trying to access the endpoint.

This should resolve temporary resolution issues with URLs and certain S3 compatiable systems such as B2 that sometimes return a 5xx error and just need a retry to be successful.

Also supports using the server context to ensure backups are terminated when a server is deleted, and removes the http call without a timeout, replacing it with a 2 hour timeout to account for connections as slow as 10Mbps on a huge file upload.
This commit is contained in:
Dane Everitt 2021-05-02 12:28:36 -07:00
parent da74ac8291
commit ddfd6d9cce
6 changed files with 239 additions and 169 deletions
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1
go.mod
View File

@ -14,6 +14,7 @@ require (
github.com/asaskevich/govalidator v0.0.0-20200907205600-7a23bdc65eef
github.com/beevik/etree v1.1.0
github.com/buger/jsonparser v1.1.0
github.com/cenkalti/backoff/v4 v4.1.0
github.com/cobaugh/osrelease v0.0.0-20181218015638-a93a0a55a249
github.com/containerd/containerd v1.4.3 // indirect
github.com/containerd/fifo v0.0.0-20201026212402-0724c46b320c // indirect

3
go.sum
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@ -73,7 +73,10 @@ github.com/bketelsen/crypt v0.0.3-0.20200106085610-5cbc8cc4026c/go.mod h1:MKsuJm
github.com/buger/jsonparser v1.1.0 h1:EPAGdKZgZCON4ZcMD+h4l/NN4ndr6ijSpj4INh8PbUY=
github.com/buger/jsonparser v1.1.0/go.mod h1:6RYKKt7H4d4+iWqouImQ9R2FZql3VbhNgx27UK13J/0=
github.com/casbin/casbin/v2 v2.1.2/go.mod h1:YcPU1XXisHhLzuxH9coDNf2FbKpjGlbCg3n9yuLkIJQ=
github.com/cenkalti/backoff v2.2.1+incompatible h1:tNowT99t7UNflLxfYYSlKYsBpXdEet03Pg2g16Swow4=
github.com/cenkalti/backoff v2.2.1+incompatible/go.mod h1:90ReRw6GdpyfrHakVjL/QHaoyV4aDUVVkXQJJJ3NXXM=
github.com/cenkalti/backoff/v4 v4.1.0 h1:c8LkOFQTzuO0WBM/ae5HdGQuZPfPxp7lqBRwQRm4fSc=
github.com/cenkalti/backoff/v4 v4.1.0/go.mod h1:scbssz8iZGpm3xbr14ovlUdkxfGXNInqkPWOWmG2CLw=
github.com/census-instrumentation/opencensus-proto v0.2.1/go.mod h1:f6KPmirojxKA12rnyqOA5BBL4O983OfeGPqjHWSTneU=
github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=

4
server/backup.go
View File

@ -66,7 +66,7 @@ func (s *Server) Backup(b backup.BackupInterface) error {
}
}
ad, err := b.Generate(s.Filesystem().Path(), ignored)
ad, err := b.Generate(s.Context(), s.Filesystem().Path(), ignored)
if err != nil {
if err := s.notifyPanelOfBackup(b.Identifier(), &backup.ArchiveDetails{}, false); err != nil {
s.Log().WithFields(log.Fields{
@ -150,7 +150,7 @@ func (s *Server) RestoreBackup(b backup.BackupInterface, reader io.ReadCloser) (
// Attempt to restore the backup to the server by running through each entry
// in the file one at a time and writing them to the disk.
s.Log().Debug("starting file writing process for backup restoration")
err = b.Restore(reader, func(file string, r io.Reader) error {
err = b.Restore(s.Context(), reader, func(file string, r io.Reader) error {
s.Events().Publish(DaemonMessageEvent, "(restoring): "+file)
return s.Filesystem().Writefile(file, r)
})

161
server/backup/backup.go
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@ -1,16 +1,18 @@
package backup
import (
"context"
"crypto/sha1"
"encoding/hex"
"io"
"os"
"path"
"sync"
"emperror.dev/errors"
"github.com/apex/log"
"github.com/pterodactyl/wings/config"
"github.com/pterodactyl/wings/remote"
"golang.org/x/sync/errgroup"
)
type AdapterType string
@ -24,20 +26,37 @@ const (
// and remote backups allowing the files to be restored.
type RestoreCallback func(file string, r io.Reader) error
type ArchiveDetails struct {
Checksum string `json:"checksum"`
ChecksumType string `json:"checksum_type"`
Size int64 `json:"size"`
}
// ToRequest returns a request object.
func (ad *ArchiveDetails) ToRequest(successful bool) remote.BackupRequest {
return remote.BackupRequest{
Checksum: ad.Checksum,
ChecksumType: ad.ChecksumType,
Size: ad.Size,
Successful: successful,
}
// noinspection GoNameStartsWithPackageName
type BackupInterface interface {
// SetClient sets the API request client on the backup interface.
SetClient(c remote.Client)
// Identifier returns the UUID of this backup as tracked by the panel
// instance.
Identifier() string
// WithLogContext attaches additional context to the log output for this
// backup.
WithLogContext(map[string]interface{})
// Generate creates a backup in whatever the configured source for the
// specific implementation is.
Generate(ctx context.Context, basePath string, ignore string) (*ArchiveDetails, error)
// Ignored returns the ignored files for this backup instance.
Ignored() string
// Checksum returns a SHA1 checksum for the generated backup.
Checksum() ([]byte, error)
// Size returns the size of the generated backup.
Size() (int64, error)
// Path returns the path to the backup on the machine. This is not always
// the final storage location of the backup, simply the location we're using
// to store it until it is moved to the final spot.
Path() string
// Details returns details about the archive.
Details(ctx context.Context) (*ArchiveDetails, error)
// Remove removes a backup file.
Remove() error
// Restore is called when a backup is ready to be restored to the disk from
// the given source. Not every backup implementation will support this nor
// will every implementation require a reader be provided.
Restore(ctx context.Context, reader io.Reader, callback RestoreCallback) error
}
type Backup struct {
@ -54,39 +73,6 @@ type Backup struct {
logContext map[string]interface{}
}
// noinspection GoNameStartsWithPackageName
type BackupInterface interface {
// SetClient sets the API request client on the backup interface.
SetClient(c remote.Client)
// Identifier returns the UUID of this backup as tracked by the panel
// instance.
Identifier() string
// WithLogContext attaches additional context to the log output for this
// backup.
WithLogContext(map[string]interface{})
// Generate creates a backup in whatever the configured source for the
// specific implementation is.
Generate(string, string) (*ArchiveDetails, error)
// Ignored returns the ignored files for this backup instance.
Ignored() string
// Checksum returns a SHA1 checksum for the generated backup.
Checksum() ([]byte, error)
// Size returns the size of the generated backup.
Size() (int64, error)
// Path returns the path to the backup on the machine. This is not always
// the final storage location of the backup, simply the location we're using
// to store it until it is moved to the final spot.
Path() string
// Details returns details about the archive.
Details() *ArchiveDetails
// Remove removes a backup file.
Remove() error
// Restore is called when a backup is ready to be restored to the disk from
// the given source. Not every backup implementation will support this nor
// will every implementation require a reader be provided.
Restore(reader io.Reader, callback RestoreCallback) error
}
func (b *Backup) SetClient(c remote.Client) {
b.client = c
}
@ -95,12 +81,12 @@ func (b *Backup) Identifier() string {
return b.Uuid
}
// Returns the path for this specific backup.
// Path returns the path for this specific backup.
func (b *Backup) Path() string {
return path.Join(config.Get().System.BackupDirectory, b.Identifier()+".tar.gz")
}
// Return the size of the generated backup.
// Size returns the size of the generated backup.
func (b *Backup) Size() (int64, error) {
st, err := os.Stat(b.Path())
if err != nil {
@ -110,7 +96,7 @@ func (b *Backup) Size() (int64, error) {
return st.Size(), nil
}
// Returns the SHA256 checksum of a backup.
// Checksum returns the SHA256 checksum of a backup.
func (b *Backup) Checksum() ([]byte, error) {
h := sha1.New()
@ -128,51 +114,34 @@ func (b *Backup) Checksum() ([]byte, error) {
return h.Sum(nil), nil
}
// Returns details of the archive by utilizing two go-routines to get the checksum and
// the size of the archive.
func (b *Backup) Details() *ArchiveDetails {
wg := sync.WaitGroup{}
wg.Add(2)
// Details returns both the checksum and size of the archive currently stored on
// the disk to the caller.
func (b *Backup) Details(ctx context.Context) (*ArchiveDetails, error) {
ad := ArchiveDetails{ChecksumType: "sha1"}
g, ctx := errgroup.WithContext(ctx)
l := log.WithField("backup_id", b.Uuid)
var checksum string
// Calculate the checksum for the file.
go func() {
defer wg.Done()
l.Info("computing checksum for backup...")
g.Go(func() error {
resp, err := b.Checksum()
if err != nil {
log.WithFields(log.Fields{
"backup": b.Identifier(),
"error": err,
}).Error("failed to calculate checksum for backup")
return
return err
}
ad.Checksum = hex.EncodeToString(resp)
return nil
})
checksum = hex.EncodeToString(resp)
l.WithField("checksum", checksum).Info("computed checksum for backup")
}()
var sz int64
go func() {
defer wg.Done()
if s, err := b.Size(); err != nil {
return
} else {
sz = s
g.Go(func() error {
s, err := b.Size()
if err != nil {
return err
}
}()
ad.Size = s
return nil
})
wg.Wait()
return &ArchiveDetails{
Checksum: checksum,
ChecksumType: "sha1",
Size: sz,
if err := g.Wait(); err != nil {
return nil, errors.WithStackDepth(err, 1)
}
return &ad, nil
}
func (b *Backup) Ignored() string {
@ -188,3 +157,19 @@ func (b *Backup) log() *log.Entry {
}
return l
}
type ArchiveDetails struct {
Checksum string `json:"checksum"`
ChecksumType string `json:"checksum_type"`
Size int64 `json:"size"`
}
// ToRequest returns a request object.
func (ad *ArchiveDetails) ToRequest(successful bool) remote.BackupRequest {
return remote.BackupRequest{
Checksum: ad.Checksum,
ChecksumType: ad.ChecksumType,
Size: ad.Size,
Successful: successful,
}
}

23
server/backup/backup_local.go
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@ -1,10 +1,11 @@
package backup
import (
"errors"
"context"
"io"
"os"
"emperror.dev/errors"
"github.com/pterodactyl/wings/server/filesystem"
"github.com/mholt/archiver/v3"
@ -56,28 +57,40 @@ func (b *LocalBackup) WithLogContext(c map[string]interface{}) {
// Generate generates a backup of the selected files and pushes it to the
// defined location for this instance.
func (b *LocalBackup) Generate(basePath, ignore string) (*ArchiveDetails, error) {
func (b *LocalBackup) Generate(ctx context.Context, basePath, ignore string) (*ArchiveDetails, error) {
a := &filesystem.Archive{
BasePath: basePath,
Ignore: ignore,
}
b.log().Info("creating backup for server...")
b.log().WithField("path", b.Path()).Info("creating backup for server")
if err := a.Create(b.Path()); err != nil {
return nil, err
}
b.log().Info("created backup successfully")
return b.Details(), nil
ad, err := b.Details(ctx)
if err != nil {
return nil, errors.WrapIf(err, "backup: failed to get archive details for local backup")
}
return ad, nil
}
// Restore will walk over the archive and call the callback function for each
// file encountered.
func (b *LocalBackup) Restore(_ io.Reader, callback RestoreCallback) error {
func (b *LocalBackup) Restore(ctx context.Context, _ io.Reader, callback RestoreCallback) error {
return archiver.Walk(b.Path(), func(f archiver.File) error {
select {
case <-ctx.Done():
// Stop walking if the context is canceled.
return archiver.ErrStopWalk
default:
{
if f.IsDir() {
return nil
}
return callback(filesystem.ExtractNameFromArchive(f), f)
}
}
})
}

208
server/backup/backup_s3.go
View File

@ -5,11 +5,15 @@ import (
"compress/gzip"
"context"
"fmt"
"github.com/pterodactyl/wings/server/filesystem"
"io"
"net/http"
"os"
"strconv"
"time"
"emperror.dev/errors"
"github.com/cenkalti/backoff/v4"
"github.com/pterodactyl/wings/server/filesystem"
"github.com/juju/ratelimit"
"github.com/pterodactyl/wings/config"
@ -45,7 +49,7 @@ func (s *S3Backup) WithLogContext(c map[string]interface{}) {
// Generate creates a new backup on the disk, moves it into the S3 bucket via
// the provided presigned URL, and then deletes the backup from the disk.
func (s *S3Backup) Generate(basePath, ignore string) (*ArchiveDetails, error) {
func (s *S3Backup) Generate(ctx context.Context, basePath, ignore string) (*ArchiveDetails, error) {
defer s.Remove()
a := &filesystem.Archive{
@ -53,7 +57,7 @@ func (s *S3Backup) Generate(basePath, ignore string) (*ArchiveDetails, error) {
Ignore: ignore,
}
s.log().Info("creating backup for server...")
s.log().WithField("path", s.Path()).Info("creating backup for server")
if err := a.Create(s.Path()); err != nil {
return nil, err
}
@ -61,29 +65,65 @@ func (s *S3Backup) Generate(basePath, ignore string) (*ArchiveDetails, error) {
rc, err := os.Open(s.Path())
if err != nil {
return nil, err
return nil, errors.Wrap(err, "backup: could not read archive from disk")
}
defer rc.Close()
if err := s.generateRemoteRequest(rc); err != nil {
if err := s.generateRemoteRequest(ctx, rc); err != nil {
return nil, err
}
return s.Details(), nil
ad, err := s.Details(ctx)
if err != nil {
return nil, errors.WrapIf(err, "backup: failed to get archive details after upload")
}
return ad, nil
}
// Reader provides a wrapper around an existing io.Reader
// but implements io.Closer in order to satisfy an io.ReadCloser.
type Reader struct {
io.Reader
// Restore will read from the provided reader assuming that it is a gzipped
// tar reader. When a file is encountered in the archive the callback function
// will be triggered. If the callback returns an error the entire process is
// stopped, otherwise this function will run until all files have been written.
//
// This restoration uses a workerpool to use up to the number of CPUs available
// on the machine when writing files to the disk.
func (s *S3Backup) Restore(ctx context.Context, r io.Reader, callback RestoreCallback) error {
reader := r
// Steal the logic we use for making backups which will be applied when restoring
// this specific backup. This allows us to prevent overloading the disk unintentionally.
if writeLimit := int64(config.Get().System.Backups.WriteLimit * 1024 * 1024); writeLimit > 0 {
reader = ratelimit.Reader(r, ratelimit.NewBucketWithRate(float64(writeLimit), writeLimit))
}
gr, err := gzip.NewReader(reader)
if err != nil {
return err
}
defer gr.Close()
tr := tar.NewReader(gr)
for {
select {
case <-ctx.Done():
return nil
default:
// Do nothing, fall through to the next block of code in this loop.
}
header, err := tr.Next()
if err != nil {
if err == io.EOF {
break
}
return err
}
if header.Typeflag == tar.TypeReg {
if err := callback(header.Name, tr); err != nil {
return err
}
}
}
func (Reader) Close() error {
return nil
}
// Generates the remote S3 request and begins the upload.
func (s *S3Backup) generateRemoteRequest(rc io.ReadCloser) error {
func (s *S3Backup) generateRemoteRequest(ctx context.Context, rc io.ReadCloser) error {
defer rc.Close()
s.log().Debug("attempting to get size of backup...")
@ -101,37 +141,7 @@ func (s *S3Backup) generateRemoteRequest(rc io.ReadCloser) error {
s.log().Debug("got S3 upload urls from the Panel")
s.log().WithField("parts", len(urls.Parts)).Info("attempting to upload backup to s3 endpoint...")
handlePart := func(part string, size int64) (string, error) {
r, err := http.NewRequest(http.MethodPut, part, nil)
if err != nil {
return "", err
}
r.ContentLength = size
r.Header.Add("Content-Length", strconv.Itoa(int(size)))
r.Header.Add("Content-Type", "application/x-gzip")
// Limit the reader to the size of the part.
r.Body = Reader{Reader: io.LimitReader(rc, size)}
// This http request can block forever due to it not having a timeout,
// but we are uploading up to 5GB of data, so there is not really
// a good way to handle a timeout on this.
res, err := http.DefaultClient.Do(r)
if err != nil {
return "", err
}
defer res.Body.Close()
// Handle non-200 status codes.
if res.StatusCode != http.StatusOK {
return "", fmt.Errorf("failed to put S3 object part, %d:%s", res.StatusCode, res.Status)
}
// Get the ETag from the uploaded part, this should be sent with the CompleteMultipartUpload request.
return res.Header.Get("ETag"), nil
}
uploader := newS3FileUploader(rc)
for i, part := range urls.Parts {
// Get the size for the current part.
var partSize int64
@ -144,7 +154,7 @@ func (s *S3Backup) generateRemoteRequest(rc io.ReadCloser) error {
}
// Attempt to upload the part.
if _, err := handlePart(part, partSize); err != nil {
if _, err := uploader.uploadPart(ctx, part, partSize); err != nil {
s.log().WithField("part_id", i+1).WithError(err).Warn("failed to upload part")
return err
}
@ -157,39 +167,97 @@ func (s *S3Backup) generateRemoteRequest(rc io.ReadCloser) error {
return nil
}
// Restore will read from the provided reader assuming that it is a gzipped
// tar reader. When a file is encountered in the archive the callback function
// will be triggered. If the callback returns an error the entire process is
// stopped, otherwise this function will run until all files have been written.
type s3FileUploader struct {
io.ReadCloser
client *http.Client
}
// newS3FileUploader returns a new file uploader instance.
func newS3FileUploader(file io.ReadCloser) *s3FileUploader {
return &s3FileUploader{
ReadCloser: file,
// We purposefully use a super high timeout on this request since we need to upload
// a 5GB file. This assumes at worst a 10Mbps connection for uploading. While technically
// you could go slower we're targeting mostly hosted servers that should have 100Mbps
// connections anyways.
client: &http.Client{Timeout: time.Hour * 2},
}
}
// backoff returns a new expoential backoff implementation using a context that
// will also stop the backoff if it is canceled.
func (fu *s3FileUploader) backoff(ctx context.Context) backoff.BackOffContext {
b := backoff.NewExponentialBackOff()
b.Multiplier = 2
b.MaxElapsedTime = time.Minute
return backoff.WithContext(b, ctx)
}
// uploadPart attempts to upload a given S3 file part to the S3 system. If a
// 5xx error is returned from the endpoint this will continue with an exponential
// backoff to try and successfully upload the part.
//
// This restoration uses a workerpool to use up to the number of CPUs available
// on the machine when writing files to the disk.
func (s *S3Backup) Restore(r io.Reader, callback RestoreCallback) error {
reader := r
// Steal the logic we use for making backups which will be applied when restoring
// this specific backup. This allows us to prevent overloading the disk unintentionally.
if writeLimit := int64(config.Get().System.Backups.WriteLimit * 1024 * 1024); writeLimit > 0 {
reader = ratelimit.Reader(r, ratelimit.NewBucketWithRate(float64(writeLimit), writeLimit))
}
gr, err := gzip.NewReader(reader)
// Once uploaded the ETag is returned to the caller.
func (fu *s3FileUploader) uploadPart(ctx context.Context, part string, size int64) (string, error) {
r, err := http.NewRequestWithContext(ctx, http.MethodPut, part, nil)
if err != nil {
return err
return "", errors.Wrap(err, "backup: could not create request for S3")
}
defer gr.Close()
tr := tar.NewReader(gr)
for {
header, err := tr.Next()
r.ContentLength = size
r.Header.Add("Content-Length", strconv.Itoa(int(size)))
r.Header.Add("Content-Type", "application/x-gzip")
// Limit the reader to the size of the part.
r.Body = Reader{Reader: io.LimitReader(fu.ReadCloser, size)}
var etag string
err = backoff.Retry(func() error {
res, err := fu.client.Do(r)
if err != nil {
if err == io.EOF {
break
if errors.Is(err, context.DeadlineExceeded) || errors.Is(err, context.Canceled) {
return backoff.Permanent(err)
}
// Don't use a permanent error here, if there is a temporary resolution error with
// the URL due to DNS issues we want to keep re-trying.
return errors.Wrap(err, "backup: S3 HTTP request failed")
}
_ = res.Body.Close()
if res.StatusCode != http.StatusOK {
err := errors.New(fmt.Sprintf("backup: failed to put S3 object: [HTTP/%d] %s", res.StatusCode, res.Status))
// Only attempt a backoff retry if this error is because of a 5xx error from
// the S3 endpoint. Any 4xx error should be treated as an error that a retry
// would not fix.
if res.StatusCode >= http.StatusInternalServerError {
return err
}
if header.Typeflag == tar.TypeReg {
if err := callback(header.Name, tr); err != nil {
return err
return backoff.Permanent(err)
}
// Get the ETag from the uploaded part, this should be sent with the
// CompleteMultipartUpload request.
etag = res.Header.Get("ETag")
return nil
}, fu.backoff(ctx))
if err != nil {
if v, ok := err.(*backoff.PermanentError); ok {
return "", v.Unwrap()
}
return "", err
}
return etag, nil
}
// Reader provides a wrapper around an existing io.Reader
// but implements io.Closer in order to satisfy an io.ReadCloser.
type Reader struct {
io.Reader
}
func (Reader) Close() error {
return nil
}