distribution/docs/storage/driver/gcs/gcs.go

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// Package gcs provides a storagedriver.StorageDriver implementation to
// store blobs in Google cloud storage.
//
// This package leverages the google.golang.org/cloud/storage client library
//for interfacing with gcs.
//
// Because gcs is a key, value store the Stat call does not support last modification
// time for directories (directories are an abstraction for key, value stores)
//
// Note that the contents of incomplete uploads are not accessible even though
// Stat returns their length
//
// +build include_gcs
package gcs
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"math/rand"
"net/http"
"net/url"
"regexp"
"sort"
"strconv"
"strings"
"time"
"golang.org/x/net/context"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"golang.org/x/oauth2/jwt"
"google.golang.org/api/googleapi"
"google.golang.org/cloud"
"google.golang.org/cloud/storage"
"github.com/Sirupsen/logrus"
ctx "github.com/docker/distribution/context"
storagedriver "github.com/docker/distribution/registry/storage/driver"
"github.com/docker/distribution/registry/storage/driver/base"
"github.com/docker/distribution/registry/storage/driver/factory"
)
const (
driverName = "gcs"
dummyProjectID = "<unknown>"
uploadSessionContentType = "application/x-docker-upload-session"
minChunkSize = 256 * 1024
maxChunkSize = 20 * minChunkSize
maxTries = 5
)
var rangeHeader = regexp.MustCompile(`^bytes=([0-9])+-([0-9]+)$`)
// driverParameters is a struct that encapsulates all of the driver parameters after all values have been set
type driverParameters struct {
bucket string
config *jwt.Config
email string
privateKey []byte
client *http.Client
rootDirectory string
}
func init() {
factory.Register(driverName, &gcsDriverFactory{})
}
// gcsDriverFactory implements the factory.StorageDriverFactory interface
type gcsDriverFactory struct{}
// Create StorageDriver from parameters
func (factory *gcsDriverFactory) Create(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
return FromParameters(parameters)
}
// driver is a storagedriver.StorageDriver implementation backed by GCS
// Objects are stored at absolute keys in the provided bucket.
type driver struct {
client *http.Client
bucket string
email string
privateKey []byte
rootDirectory string
}
// FromParameters constructs a new Driver with a given parameters map
// Required parameters:
// - bucket
func FromParameters(parameters map[string]interface{}) (storagedriver.StorageDriver, error) {
bucket, ok := parameters["bucket"]
if !ok || fmt.Sprint(bucket) == "" {
return nil, fmt.Errorf("No bucket parameter provided")
}
rootDirectory, ok := parameters["rootdirectory"]
if !ok {
rootDirectory = ""
}
var ts oauth2.TokenSource
jwtConf := new(jwt.Config)
if keyfile, ok := parameters["keyfile"]; ok {
jsonKey, err := ioutil.ReadFile(fmt.Sprint(keyfile))
if err != nil {
return nil, err
}
jwtConf, err = google.JWTConfigFromJSON(jsonKey, storage.ScopeFullControl)
if err != nil {
return nil, err
}
ts = jwtConf.TokenSource(context.Background())
} else {
var err error
ts, err = google.DefaultTokenSource(context.Background(), storage.ScopeFullControl)
if err != nil {
return nil, err
}
}
params := driverParameters{
bucket: fmt.Sprint(bucket),
rootDirectory: fmt.Sprint(rootDirectory),
email: jwtConf.Email,
privateKey: jwtConf.PrivateKey,
client: oauth2.NewClient(context.Background(), ts),
}
return New(params)
}
// New constructs a new driver
func New(params driverParameters) (storagedriver.StorageDriver, error) {
rootDirectory := strings.Trim(params.rootDirectory, "/")
if rootDirectory != "" {
rootDirectory += "/"
}
d := &driver{
bucket: params.bucket,
rootDirectory: rootDirectory,
email: params.email,
privateKey: params.privateKey,
client: params.client,
}
return &base.Base{
StorageDriver: d,
}, nil
}
// Implement the storagedriver.StorageDriver interface
func (d *driver) Name() string {
return driverName
}
// GetContent retrieves the content stored at "path" as a []byte.
// This should primarily be used for small objects.
func (d *driver) GetContent(context ctx.Context, path string) ([]byte, error) {
gcsContext := d.context(context)
name := d.pathToKey(path)
var rc io.ReadCloser
err := retry(func() error {
var err error
rc, err = storage.NewReader(gcsContext, d.bucket, name)
return err
})
if err == storage.ErrObjectNotExist {
return nil, storagedriver.PathNotFoundError{Path: path}
}
if err != nil {
return nil, err
}
defer rc.Close()
p, err := ioutil.ReadAll(rc)
if err != nil {
return nil, err
}
return p, nil
}
// PutContent stores the []byte content at a location designated by "path".
// This should primarily be used for small objects.
func (d *driver) PutContent(context ctx.Context, path string, contents []byte) error {
return retry(func() error {
wc := storage.NewWriter(d.context(context), d.bucket, d.pathToKey(path))
wc.ContentType = "application/octet-stream"
return putContentsClose(wc, contents)
})
}
// Reader retrieves an io.ReadCloser for the content stored at "path"
// with a given byte offset.
// May be used to resume reading a stream by providing a nonzero offset.
func (d *driver) Reader(context ctx.Context, path string, offset int64) (io.ReadCloser, error) {
res, err := getObject(d.client, d.bucket, d.pathToKey(path), offset)
if err != nil {
if res != nil {
if res.StatusCode == http.StatusNotFound {
res.Body.Close()
return nil, storagedriver.PathNotFoundError{Path: path}
}
if res.StatusCode == http.StatusRequestedRangeNotSatisfiable {
res.Body.Close()
obj, err := storageStatObject(d.context(context), d.bucket, d.pathToKey(path))
if err != nil {
return nil, err
}
if offset == int64(obj.Size) {
return ioutil.NopCloser(bytes.NewReader([]byte{})), nil
}
return nil, storagedriver.InvalidOffsetError{Path: path, Offset: offset}
}
}
return nil, err
}
if res.Header.Get("Content-Type") == uploadSessionContentType {
defer res.Body.Close()
return nil, storagedriver.PathNotFoundError{Path: path}
}
return res.Body, nil
}
func getObject(client *http.Client, bucket string, name string, offset int64) (*http.Response, error) {
// copied from google.golang.org/cloud/storage#NewReader :
// to set the additional "Range" header
u := &url.URL{
Scheme: "https",
Host: "storage.googleapis.com",
Path: fmt.Sprintf("/%s/%s", bucket, name),
}
req, err := http.NewRequest("GET", u.String(), nil)
if err != nil {
return nil, err
}
if offset > 0 {
req.Header.Set("Range", fmt.Sprintf("bytes=%v-", offset))
}
var res *http.Response
err = retry(func() error {
var err error
res, err = client.Do(req)
return err
})
if err != nil {
return nil, err
}
return res, googleapi.CheckMediaResponse(res)
}
// Writer returns a FileWriter which will store the content written to it
// at the location designated by "path" after the call to Commit.
func (d *driver) Writer(context ctx.Context, path string, append bool) (storagedriver.FileWriter, error) {
writer := &writer{
client: d.client,
bucket: d.bucket,
name: d.pathToKey(path),
buffer: make([]byte, maxChunkSize),
}
if append {
err := writer.init(path)
if err != nil {
return nil, err
}
}
return writer, nil
}
type writer struct {
client *http.Client
bucket string
name string
size int64
offset int64
closed bool
sessionURI string
buffer []byte
buffSize int
}
// Cancel removes any written content from this FileWriter.
func (w *writer) Cancel() error {
err := w.checkClosed()
if err != nil {
return err
}
w.closed = true
err = storageDeleteObject(cloud.NewContext(dummyProjectID, w.client), w.bucket, w.name)
if err != nil {
if status, ok := err.(*googleapi.Error); ok {
if status.Code == http.StatusNotFound {
err = nil
}
}
}
return err
}
func (w *writer) Close() error {
if w.closed {
return nil
}
w.closed = true
err := w.writeChunk()
if err != nil {
return err
}
// Copy the remaining bytes from the buffer to the upload session
// Normally buffSize will be smaller than minChunkSize. However, in the
// unlikely event that the upload session failed to start, this number could be higher.
// In this case we can safely clip the remaining bytes to the minChunkSize
if w.buffSize > minChunkSize {
w.buffSize = minChunkSize
}
// commit the writes by updating the upload session
err = retry(func() error {
wc := storage.NewWriter(cloud.NewContext(dummyProjectID, w.client), w.bucket, w.name)
wc.ContentType = uploadSessionContentType
wc.Metadata = map[string]string{
"Session-URI": w.sessionURI,
"Offset": strconv.FormatInt(w.offset, 10),
}
return putContentsClose(wc, w.buffer[0:w.buffSize])
})
if err != nil {
return err
}
w.size = w.offset + int64(w.buffSize)
w.buffSize = 0
return nil
}
func putContentsClose(wc *storage.Writer, contents []byte) error {
size := len(contents)
var nn int
var err error
for nn < size {
n, err := wc.Write(contents[nn:size])
nn += n
if err != nil {
break
}
}
if err != nil {
wc.CloseWithError(err)
return err
}
return wc.Close()
}
// Commit flushes all content written to this FileWriter and makes it
// available for future calls to StorageDriver.GetContent and
// StorageDriver.Reader.
func (w *writer) Commit() error {
if err := w.checkClosed(); err != nil {
return err
}
w.closed = true
// no session started yet just perform a simple upload
if w.sessionURI == "" {
err := retry(func() error {
wc := storage.NewWriter(cloud.NewContext(dummyProjectID, w.client), w.bucket, w.name)
wc.ContentType = "application/octet-stream"
return putContentsClose(wc, w.buffer[0:w.buffSize])
})
if err != nil {
return err
}
w.size = w.offset + int64(w.buffSize)
w.buffSize = 0
return nil
}
size := w.offset + int64(w.buffSize)
var nn int
// loop must be performed at least once to ensure the file is committed even when
// the buffer is empty
for {
n, err := putChunk(w.client, w.sessionURI, w.buffer[nn:w.buffSize], w.offset, size)
nn += int(n)
w.offset += n
w.size = w.offset
if err != nil {
w.buffSize = copy(w.buffer, w.buffer[nn:w.buffSize])
return err
}
if nn == w.buffSize {
break
}
}
w.buffSize = 0
return nil
}
func (w *writer) checkClosed() error {
if w.closed {
return fmt.Errorf("Writer already closed")
}
return nil
}
func (w *writer) writeChunk() error {
var err error
// chunks can be uploaded only in multiples of minChunkSize
// chunkSize is a multiple of minChunkSize less than or equal to buffSize
chunkSize := w.buffSize - (w.buffSize % minChunkSize)
if chunkSize == 0 {
return nil
}
// if their is no sessionURI yet, obtain one by starting the session
if w.sessionURI == "" {
w.sessionURI, err = startSession(w.client, w.bucket, w.name)
}
if err != nil {
return err
}
nn, err := putChunk(w.client, w.sessionURI, w.buffer[0:chunkSize], w.offset, -1)
w.offset += nn
if w.offset > w.size {
w.size = w.offset
}
// shift the remaining bytes to the start of the buffer
w.buffSize = copy(w.buffer, w.buffer[int(nn):w.buffSize])
return err
}
func (w *writer) Write(p []byte) (int, error) {
err := w.checkClosed()
if err != nil {
return 0, err
}
var nn int
for nn < len(p) {
n := copy(w.buffer[w.buffSize:], p[nn:])
w.buffSize += n
if w.buffSize == cap(w.buffer) {
err = w.writeChunk()
if err != nil {
break
}
}
nn += n
}
return nn, err
}
// Size returns the number of bytes written to this FileWriter.
func (w *writer) Size() int64 {
return w.size
}
func (w *writer) init(path string) error {
res, err := getObject(w.client, w.bucket, w.name, 0)
if err != nil {
return err
}
defer res.Body.Close()
if res.Header.Get("Content-Type") != uploadSessionContentType {
return storagedriver.PathNotFoundError{Path: path}
}
offset, err := strconv.ParseInt(res.Header.Get("X-Goog-Meta-Offset"), 10, 64)
if err != nil {
return err
}
buffer, err := ioutil.ReadAll(res.Body)
if err != nil {
return err
}
w.sessionURI = res.Header.Get("X-Goog-Meta-Session-URI")
w.buffSize = copy(w.buffer, buffer)
w.offset = offset
w.size = offset + int64(w.buffSize)
return nil
}
type request func() error
func retry(req request) error {
backoff := time.Second
var err error
for i := 0; i < maxTries; i++ {
err = req()
if err == nil {
return nil
}
status, ok := err.(*googleapi.Error)
if !ok || (status.Code != 429 && status.Code < http.StatusInternalServerError) {
return err
}
time.Sleep(backoff - time.Second + (time.Duration(rand.Int31n(1000)) * time.Millisecond))
if i <= 4 {
backoff = backoff * 2
}
}
return err
}
// Stat retrieves the FileInfo for the given path, including the current
// size in bytes and the creation time.
func (d *driver) Stat(context ctx.Context, path string) (storagedriver.FileInfo, error) {
var fi storagedriver.FileInfoFields
//try to get as file
gcsContext := d.context(context)
obj, err := storageStatObject(gcsContext, d.bucket, d.pathToKey(path))
if err == nil {
if obj.ContentType == uploadSessionContentType {
return nil, storagedriver.PathNotFoundError{Path: path}
}
fi = storagedriver.FileInfoFields{
Path: path,
Size: obj.Size,
ModTime: obj.Updated,
IsDir: false,
}
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
}
//try to get as folder
dirpath := d.pathToDirKey(path)
var query *storage.Query
query = &storage.Query{}
query.Prefix = dirpath
query.MaxResults = 1
objects, err := storageListObjects(gcsContext, d.bucket, query)
if err != nil {
return nil, err
}
if len(objects.Results) < 1 {
return nil, storagedriver.PathNotFoundError{Path: path}
}
fi = storagedriver.FileInfoFields{
Path: path,
IsDir: true,
}
obj = objects.Results[0]
if obj.Name == dirpath {
fi.Size = obj.Size
fi.ModTime = obj.Updated
}
return storagedriver.FileInfoInternal{FileInfoFields: fi}, nil
}
// List returns a list of the objects that are direct descendants of the
//given path.
func (d *driver) List(context ctx.Context, path string) ([]string, error) {
var query *storage.Query
query = &storage.Query{}
query.Delimiter = "/"
query.Prefix = d.pathToDirKey(path)
list := make([]string, 0, 64)
for {
objects, err := storageListObjects(d.context(context), d.bucket, query)
if err != nil {
return nil, err
}
for _, object := range objects.Results {
// GCS does not guarantee strong consistency between
// DELETE and LIST operations. Check that the object is not deleted,
// and filter out any objects with a non-zero time-deleted
if object.Deleted.IsZero() && object.ContentType != uploadSessionContentType {
list = append(list, d.keyToPath(object.Name))
}
}
for _, subpath := range objects.Prefixes {
subpath = d.keyToPath(subpath)
list = append(list, subpath)
}
query = objects.Next
if query == nil {
break
}
}
if path != "/" && len(list) == 0 {
// Treat empty response as missing directory, since we don't actually
// have directories in Google Cloud Storage.
return nil, storagedriver.PathNotFoundError{Path: path}
}
return list, nil
}
// Move moves an object stored at sourcePath to destPath, removing the
// original object.
func (d *driver) Move(context ctx.Context, sourcePath string, destPath string) error {
gcsContext := d.context(context)
_, err := storageCopyObject(gcsContext, d.bucket, d.pathToKey(sourcePath), d.bucket, d.pathToKey(destPath), nil)
if err != nil {
if status, ok := err.(*googleapi.Error); ok {
if status.Code == http.StatusNotFound {
return storagedriver.PathNotFoundError{Path: sourcePath}
}
}
return err
}
err = storageDeleteObject(gcsContext, d.bucket, d.pathToKey(sourcePath))
// if deleting the file fails, log the error, but do not fail; the file was successfully copied,
// and the original should eventually be cleaned when purging the uploads folder.
if err != nil {
logrus.Infof("error deleting file: %v due to %v", sourcePath, err)
}
return nil
}
// listAll recursively lists all names of objects stored at "prefix" and its subpaths.
func (d *driver) listAll(context context.Context, prefix string) ([]string, error) {
list := make([]string, 0, 64)
query := &storage.Query{}
query.Prefix = prefix
query.Versions = false
for {
objects, err := storageListObjects(d.context(context), d.bucket, query)
if err != nil {
return nil, err
}
for _, obj := range objects.Results {
// GCS does not guarantee strong consistency between
// DELETE and LIST operations. Check that the object is not deleted,
// and filter out any objects with a non-zero time-deleted
if obj.Deleted.IsZero() {
list = append(list, obj.Name)
}
}
query = objects.Next
if query == nil {
break
}
}
return list, nil
}
// Delete recursively deletes all objects stored at "path" and its subpaths.
func (d *driver) Delete(context ctx.Context, path string) error {
prefix := d.pathToDirKey(path)
gcsContext := d.context(context)
keys, err := d.listAll(gcsContext, prefix)
if err != nil {
return err
}
if len(keys) > 0 {
sort.Sort(sort.Reverse(sort.StringSlice(keys)))
for _, key := range keys {
err := storageDeleteObject(gcsContext, d.bucket, key)
// GCS only guarantees eventual consistency, so listAll might return
// paths that no longer exist. If this happens, just ignore any not
// found error
if status, ok := err.(*googleapi.Error); ok {
if status.Code == http.StatusNotFound {
err = nil
}
}
if err != nil {
return err
}
}
return nil
}
err = storageDeleteObject(gcsContext, d.bucket, d.pathToKey(path))
if err != nil {
if status, ok := err.(*googleapi.Error); ok {
if status.Code == http.StatusNotFound {
return storagedriver.PathNotFoundError{Path: path}
}
}
}
return err
}
func storageDeleteObject(context context.Context, bucket string, name string) error {
return retry(func() error {
return storage.DeleteObject(context, bucket, name)
})
}
func storageStatObject(context context.Context, bucket string, name string) (*storage.Object, error) {
var obj *storage.Object
err := retry(func() error {
var err error
obj, err = storage.StatObject(context, bucket, name)
return err
})
return obj, err
}
func storageListObjects(context context.Context, bucket string, q *storage.Query) (*storage.Objects, error) {
var objs *storage.Objects
err := retry(func() error {
var err error
objs, err = storage.ListObjects(context, bucket, q)
return err
})
return objs, err
}
func storageCopyObject(context context.Context, srcBucket, srcName string, destBucket, destName string, attrs *storage.ObjectAttrs) (*storage.Object, error) {
var obj *storage.Object
err := retry(func() error {
var err error
obj, err = storage.CopyObject(context, srcBucket, srcName, destBucket, destName, attrs)
return err
})
return obj, err
}
// URLFor returns a URL which may be used to retrieve the content stored at
// the given path, possibly using the given options.
// Returns ErrUnsupportedMethod if this driver has no privateKey
func (d *driver) URLFor(context ctx.Context, path string, options map[string]interface{}) (string, error) {
if d.privateKey == nil {
return "", storagedriver.ErrUnsupportedMethod{}
}
name := d.pathToKey(path)
methodString := "GET"
method, ok := options["method"]
if ok {
methodString, ok = method.(string)
if !ok || (methodString != "GET" && methodString != "HEAD") {
return "", storagedriver.ErrUnsupportedMethod{}
}
}
expiresTime := time.Now().Add(20 * time.Minute)
expires, ok := options["expiry"]
if ok {
et, ok := expires.(time.Time)
if ok {
expiresTime = et
}
}
opts := &storage.SignedURLOptions{
GoogleAccessID: d.email,
PrivateKey: d.privateKey,
Method: methodString,
Expires: expiresTime,
}
return storage.SignedURL(d.bucket, name, opts)
}
func startSession(client *http.Client, bucket string, name string) (uri string, err error) {
u := &url.URL{
Scheme: "https",
Host: "www.googleapis.com",
Path: fmt.Sprintf("/upload/storage/v1/b/%v/o", bucket),
RawQuery: fmt.Sprintf("uploadType=resumable&name=%v", name),
}
err = retry(func() error {
req, err := http.NewRequest("POST", u.String(), nil)
if err != nil {
return err
}
req.Header.Set("X-Upload-Content-Type", "application/octet-stream")
req.Header.Set("Content-Length", "0")
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
err = googleapi.CheckMediaResponse(resp)
if err != nil {
return err
}
uri = resp.Header.Get("Location")
return nil
})
return uri, err
}
func putChunk(client *http.Client, sessionURI string, chunk []byte, from int64, totalSize int64) (int64, error) {
bytesPut := int64(0)
err := retry(func() error {
req, err := http.NewRequest("PUT", sessionURI, bytes.NewReader(chunk))
if err != nil {
return err
}
length := int64(len(chunk))
to := from + length - 1
size := "*"
if totalSize >= 0 {
size = strconv.FormatInt(totalSize, 10)
}
req.Header.Set("Content-Type", "application/octet-stream")
if from == to+1 {
req.Header.Set("Content-Range", fmt.Sprintf("bytes */%v", size))
} else {
req.Header.Set("Content-Range", fmt.Sprintf("bytes %v-%v/%v", from, to, size))
}
req.Header.Set("Content-Length", strconv.FormatInt(length, 10))
resp, err := client.Do(req)
if err != nil {
return err
}
defer resp.Body.Close()
if totalSize < 0 && resp.StatusCode == 308 {
groups := rangeHeader.FindStringSubmatch(resp.Header.Get("Range"))
end, err := strconv.ParseInt(groups[2], 10, 64)
if err != nil {
return err
}
bytesPut = end - from + 1
return nil
}
err = googleapi.CheckMediaResponse(resp)
if err != nil {
return err
}
bytesPut = to - from + 1
return nil
})
return bytesPut, err
}
func (d *driver) context(context ctx.Context) context.Context {
return cloud.WithContext(context, dummyProjectID, d.client)
}
func (d *driver) pathToKey(path string) string {
return strings.TrimRight(d.rootDirectory+strings.TrimLeft(path, "/"), "/")
}
func (d *driver) pathToDirKey(path string) string {
return d.pathToKey(path) + "/"
}
func (d *driver) keyToPath(key string) string {
return "/" + strings.Trim(strings.TrimPrefix(key, d.rootDirectory), "/")
}