githaven/routers/api/packages/container/container.go
KN4CK3R 064f05204c
Add endpoint for not implemented Docker auth (#28457)
Recently Docker started to use the optional `POST /v2/token` endpoint
which should respond with a `404 Not Found` status code instead of the
current `405 Method Not Allowed`.

> Note: Not all token servers implement oauth2. If the request to the
endpoint returns 404 using the HTTP POST method, refer to Token
Documentation for using the HTTP GET method supported by all token
servers.
2023-12-13 15:23:53 -05:00

773 lines
22 KiB
Go

// Copyright 2021 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package container
import (
"errors"
"fmt"
"io"
"net/http"
"net/url"
"os"
"regexp"
"strconv"
"strings"
packages_model "code.gitea.io/gitea/models/packages"
container_model "code.gitea.io/gitea/models/packages/container"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/context"
"code.gitea.io/gitea/modules/json"
"code.gitea.io/gitea/modules/log"
packages_module "code.gitea.io/gitea/modules/packages"
container_module "code.gitea.io/gitea/modules/packages/container"
"code.gitea.io/gitea/modules/setting"
"code.gitea.io/gitea/modules/util"
"code.gitea.io/gitea/routers/api/packages/helper"
packages_service "code.gitea.io/gitea/services/packages"
container_service "code.gitea.io/gitea/services/packages/container"
digest "github.com/opencontainers/go-digest"
)
// maximum size of a container manifest
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pushing-manifests
const maxManifestSize = 10 * 1024 * 1024
var (
imageNamePattern = regexp.MustCompile(`\A[a-z0-9]+([._-][a-z0-9]+)*(/[a-z0-9]+([._-][a-z0-9]+)*)*\z`)
referencePattern = regexp.MustCompile(`\A[a-zA-Z0-9_][a-zA-Z0-9._-]{0,127}\z`)
)
type containerHeaders struct {
Status int
ContentDigest string
UploadUUID string
Range string
Location string
ContentType string
ContentLength int64
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#legacy-docker-support-http-headers
func setResponseHeaders(resp http.ResponseWriter, h *containerHeaders) {
if h.Location != "" {
resp.Header().Set("Location", h.Location)
}
if h.Range != "" {
resp.Header().Set("Range", h.Range)
}
if h.ContentType != "" {
resp.Header().Set("Content-Type", h.ContentType)
}
if h.ContentLength != 0 {
resp.Header().Set("Content-Length", strconv.FormatInt(h.ContentLength, 10))
}
if h.UploadUUID != "" {
resp.Header().Set("Docker-Upload-Uuid", h.UploadUUID)
}
if h.ContentDigest != "" {
resp.Header().Set("Docker-Content-Digest", h.ContentDigest)
resp.Header().Set("ETag", fmt.Sprintf(`"%s"`, h.ContentDigest))
}
resp.Header().Set("Docker-Distribution-Api-Version", "registry/2.0")
resp.WriteHeader(h.Status)
}
func jsonResponse(ctx *context.Context, status int, obj any) {
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: status,
ContentType: "application/json",
})
if err := json.NewEncoder(ctx.Resp).Encode(obj); err != nil {
log.Error("JSON encode: %v", err)
}
}
func apiError(ctx *context.Context, status int, err error) {
helper.LogAndProcessError(ctx, status, err, func(message string) {
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: status,
})
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#error-codes
func apiErrorDefined(ctx *context.Context, err *namedError) {
type ContainerError struct {
Code string `json:"code"`
Message string `json:"message"`
}
type ContainerErrors struct {
Errors []ContainerError `json:"errors"`
}
jsonResponse(ctx, err.StatusCode, ContainerErrors{
Errors: []ContainerError{
{
Code: err.Code,
Message: err.Message,
},
},
})
}
// ReqContainerAccess is a middleware which checks the current user valid (real user or ghost for anonymous access)
func ReqContainerAccess(ctx *context.Context) {
if ctx.Doer == nil {
ctx.Resp.Header().Add("WWW-Authenticate", `Bearer realm="`+setting.AppURL+`v2/token",service="container_registry",scope="*"`)
apiErrorDefined(ctx, errUnauthorized)
}
}
// VerifyImageName is a middleware which checks if the image name is allowed
func VerifyImageName(ctx *context.Context) {
if !imageNamePattern.MatchString(ctx.Params("image")) {
apiErrorDefined(ctx, errNameInvalid)
}
}
// DetermineSupport is used to test if the registry supports OCI
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#determining-support
func DetermineSupport(ctx *context.Context) {
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: http.StatusOK,
})
}
// Authenticate creates a token for the current user
// If the current user is anonymous, the ghost user is used
func Authenticate(ctx *context.Context) {
u := ctx.Doer
if u == nil {
u = user_model.NewGhostUser()
}
token, err := packages_service.CreateAuthorizationToken(u)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
ctx.JSON(http.StatusOK, map[string]string{
"token": token,
})
}
// https://distribution.github.io/distribution/spec/auth/oauth/
func AuthenticateNotImplemented(ctx *context.Context) {
// This optional endpoint can be used to authenticate a client.
// It must implement the specification described in:
// https://datatracker.ietf.org/doc/html/rfc6749
// https://distribution.github.io/distribution/spec/auth/oauth/
// Purpose of this stub is to respond with 404 Not Found instead of 405 Method Not Allowed.
ctx.Status(http.StatusNotFound)
}
// https://docs.docker.com/registry/spec/api/#listing-repositories
func GetRepositoryList(ctx *context.Context) {
n := ctx.FormInt("n")
if n <= 0 || n > 100 {
n = 100
}
last := ctx.FormTrim("last")
repositories, err := container_model.GetRepositories(ctx, ctx.Doer, n, last)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
type RepositoryList struct {
Repositories []string `json:"repositories"`
}
if len(repositories) == n {
v := url.Values{}
if n > 0 {
v.Add("n", strconv.Itoa(n))
}
v.Add("last", repositories[len(repositories)-1])
ctx.Resp.Header().Set("Link", fmt.Sprintf(`</v2/_catalog?%s>; rel="next"`, v.Encode()))
}
jsonResponse(ctx, http.StatusOK, RepositoryList{
Repositories: repositories,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#mounting-a-blob-from-another-repository
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#single-post
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pushing-a-blob-in-chunks
func InitiateUploadBlob(ctx *context.Context) {
image := ctx.Params("image")
mount := ctx.FormTrim("mount")
from := ctx.FormTrim("from")
if mount != "" {
blob, _ := workaroundGetContainerBlob(ctx, &container_model.BlobSearchOptions{
Repository: from,
Digest: mount,
})
if blob != nil {
accessible, err := packages_model.IsBlobAccessibleForUser(ctx, blob.Blob.ID, ctx.Doer)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
if accessible {
if err := mountBlob(ctx, &packages_service.PackageInfo{Owner: ctx.Package.Owner, Name: image}, blob.Blob); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/blobs/%s", ctx.Package.Owner.LowerName, image, mount),
ContentDigest: mount,
Status: http.StatusCreated,
})
return
}
}
}
digest := ctx.FormTrim("digest")
if digest != "" {
buf, err := packages_module.CreateHashedBufferFromReader(ctx.Req.Body)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
defer buf.Close()
if digest != digestFromHashSummer(buf) {
apiErrorDefined(ctx, errDigestInvalid)
return
}
if _, err := saveAsPackageBlob(ctx,
buf,
&packages_service.PackageCreationInfo{
PackageInfo: packages_service.PackageInfo{
Owner: ctx.Package.Owner,
Name: image,
},
Creator: ctx.Doer,
},
); err != nil {
switch err {
case packages_service.ErrQuotaTotalCount, packages_service.ErrQuotaTypeSize, packages_service.ErrQuotaTotalSize:
apiError(ctx, http.StatusForbidden, err)
default:
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/blobs/%s", ctx.Package.Owner.LowerName, image, digest),
ContentDigest: digest,
Status: http.StatusCreated,
})
return
}
upload, err := packages_model.CreateBlobUpload(ctx)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/blobs/uploads/%s", ctx.Package.Owner.LowerName, image, upload.ID),
Range: "0-0",
UploadUUID: upload.ID,
Status: http.StatusAccepted,
})
}
// https://docs.docker.com/registry/spec/api/#get-blob-upload
func GetUploadBlob(ctx *context.Context) {
uuid := ctx.Params("uuid")
upload, err := packages_model.GetBlobUploadByID(ctx, uuid)
if err != nil {
if err == packages_model.ErrPackageBlobUploadNotExist {
apiErrorDefined(ctx, errBlobUploadUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Range: fmt.Sprintf("0-%d", upload.BytesReceived),
UploadUUID: upload.ID,
Status: http.StatusNoContent,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pushing-a-blob-in-chunks
func UploadBlob(ctx *context.Context) {
image := ctx.Params("image")
uploader, err := container_service.NewBlobUploader(ctx, ctx.Params("uuid"))
if err != nil {
if err == packages_model.ErrPackageBlobUploadNotExist {
apiErrorDefined(ctx, errBlobUploadUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
defer uploader.Close()
contentRange := ctx.Req.Header.Get("Content-Range")
if contentRange != "" {
start, end := 0, 0
if _, err := fmt.Sscanf(contentRange, "%d-%d", &start, &end); err != nil {
apiErrorDefined(ctx, errBlobUploadInvalid)
return
}
if int64(start) != uploader.Size() {
apiErrorDefined(ctx, errBlobUploadInvalid.WithStatusCode(http.StatusRequestedRangeNotSatisfiable))
return
}
} else if uploader.Size() != 0 {
apiErrorDefined(ctx, errBlobUploadInvalid.WithMessage("Stream uploads after first write are not allowed"))
return
}
if err := uploader.Append(ctx, ctx.Req.Body); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/blobs/uploads/%s", ctx.Package.Owner.LowerName, image, uploader.ID),
Range: fmt.Sprintf("0-%d", uploader.Size()-1),
UploadUUID: uploader.ID,
Status: http.StatusAccepted,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pushing-a-blob-in-chunks
func EndUploadBlob(ctx *context.Context) {
image := ctx.Params("image")
digest := ctx.FormTrim("digest")
if digest == "" {
apiErrorDefined(ctx, errDigestInvalid)
return
}
uploader, err := container_service.NewBlobUploader(ctx, ctx.Params("uuid"))
if err != nil {
if err == packages_model.ErrPackageBlobUploadNotExist {
apiErrorDefined(ctx, errBlobUploadUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
close := true
defer func() {
if close {
uploader.Close()
}
}()
if ctx.Req.Body != nil {
if err := uploader.Append(ctx, ctx.Req.Body); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
}
if digest != digestFromHashSummer(uploader) {
apiErrorDefined(ctx, errDigestInvalid)
return
}
if _, err := saveAsPackageBlob(ctx,
uploader,
&packages_service.PackageCreationInfo{
PackageInfo: packages_service.PackageInfo{
Owner: ctx.Package.Owner,
Name: image,
},
Creator: ctx.Doer,
},
); err != nil {
switch err {
case packages_service.ErrQuotaTotalCount, packages_service.ErrQuotaTypeSize, packages_service.ErrQuotaTotalSize:
apiError(ctx, http.StatusForbidden, err)
default:
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
if err := uploader.Close(); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
close = false
if err := container_service.RemoveBlobUploadByID(ctx, uploader.ID); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/blobs/%s", ctx.Package.Owner.LowerName, image, digest),
ContentDigest: digest,
Status: http.StatusCreated,
})
}
// https://docs.docker.com/registry/spec/api/#delete-blob-upload
func CancelUploadBlob(ctx *context.Context) {
uuid := ctx.Params("uuid")
_, err := packages_model.GetBlobUploadByID(ctx, uuid)
if err != nil {
if err == packages_model.ErrPackageBlobUploadNotExist {
apiErrorDefined(ctx, errBlobUploadUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
if err := container_service.RemoveBlobUploadByID(ctx, uuid); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: http.StatusNoContent,
})
}
func getBlobFromContext(ctx *context.Context) (*packages_model.PackageFileDescriptor, error) {
d := ctx.Params("digest")
if digest.Digest(d).Validate() != nil {
return nil, container_model.ErrContainerBlobNotExist
}
return workaroundGetContainerBlob(ctx, &container_model.BlobSearchOptions{
OwnerID: ctx.Package.Owner.ID,
Image: ctx.Params("image"),
Digest: d,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#checking-if-content-exists-in-the-registry
func HeadBlob(ctx *context.Context) {
blob, err := getBlobFromContext(ctx)
if err != nil {
if err == container_model.ErrContainerBlobNotExist {
apiErrorDefined(ctx, errBlobUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
ContentDigest: blob.Properties.GetByName(container_module.PropertyDigest),
ContentLength: blob.Blob.Size,
Status: http.StatusOK,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pulling-blobs
func GetBlob(ctx *context.Context) {
blob, err := getBlobFromContext(ctx)
if err != nil {
if err == container_model.ErrContainerBlobNotExist {
apiErrorDefined(ctx, errBlobUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
serveBlob(ctx, blob)
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#deleting-blobs
func DeleteBlob(ctx *context.Context) {
d := ctx.Params("digest")
if digest.Digest(d).Validate() != nil {
apiErrorDefined(ctx, errBlobUnknown)
return
}
if err := deleteBlob(ctx, ctx.Package.Owner.ID, ctx.Params("image"), d); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: http.StatusAccepted,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pushing-manifests
func UploadManifest(ctx *context.Context) {
reference := ctx.Params("reference")
mci := &manifestCreationInfo{
MediaType: ctx.Req.Header.Get("Content-Type"),
Owner: ctx.Package.Owner,
Creator: ctx.Doer,
Image: ctx.Params("image"),
Reference: reference,
IsTagged: digest.Digest(reference).Validate() != nil,
}
if mci.IsTagged && !referencePattern.MatchString(reference) {
apiErrorDefined(ctx, errManifestInvalid.WithMessage("Tag is invalid"))
return
}
maxSize := maxManifestSize + 1
buf, err := packages_module.CreateHashedBufferFromReaderWithSize(&io.LimitedReader{R: ctx.Req.Body, N: int64(maxSize)}, maxSize)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
defer buf.Close()
if buf.Size() > maxManifestSize {
apiErrorDefined(ctx, errManifestInvalid.WithMessage("Manifest exceeds maximum size").WithStatusCode(http.StatusRequestEntityTooLarge))
return
}
digest, err := processManifest(ctx, mci, buf)
if err != nil {
var namedError *namedError
if errors.As(err, &namedError) {
apiErrorDefined(ctx, namedError)
} else if errors.Is(err, container_model.ErrContainerBlobNotExist) {
apiErrorDefined(ctx, errBlobUnknown)
} else {
switch err {
case packages_service.ErrQuotaTotalCount, packages_service.ErrQuotaTypeSize, packages_service.ErrQuotaTotalSize:
apiError(ctx, http.StatusForbidden, err)
default:
apiError(ctx, http.StatusInternalServerError, err)
}
}
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Location: fmt.Sprintf("/v2/%s/%s/manifests/%s", ctx.Package.Owner.LowerName, mci.Image, reference),
ContentDigest: digest,
Status: http.StatusCreated,
})
}
func getBlobSearchOptionsFromContext(ctx *context.Context) (*container_model.BlobSearchOptions, error) {
reference := ctx.Params("reference")
opts := &container_model.BlobSearchOptions{
OwnerID: ctx.Package.Owner.ID,
Image: ctx.Params("image"),
IsManifest: true,
}
if digest.Digest(reference).Validate() == nil {
opts.Digest = reference
} else if referencePattern.MatchString(reference) {
opts.Tag = reference
} else {
return nil, container_model.ErrContainerBlobNotExist
}
return opts, nil
}
func getManifestFromContext(ctx *context.Context) (*packages_model.PackageFileDescriptor, error) {
opts, err := getBlobSearchOptionsFromContext(ctx)
if err != nil {
return nil, err
}
return workaroundGetContainerBlob(ctx, opts)
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#checking-if-content-exists-in-the-registry
func HeadManifest(ctx *context.Context) {
manifest, err := getManifestFromContext(ctx)
if err != nil {
if err == container_model.ErrContainerBlobNotExist {
apiErrorDefined(ctx, errManifestUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
setResponseHeaders(ctx.Resp, &containerHeaders{
ContentDigest: manifest.Properties.GetByName(container_module.PropertyDigest),
ContentType: manifest.Properties.GetByName(container_module.PropertyMediaType),
ContentLength: manifest.Blob.Size,
Status: http.StatusOK,
})
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#pulling-manifests
func GetManifest(ctx *context.Context) {
manifest, err := getManifestFromContext(ctx)
if err != nil {
if err == container_model.ErrContainerBlobNotExist {
apiErrorDefined(ctx, errManifestUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
serveBlob(ctx, manifest)
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#deleting-tags
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#deleting-manifests
func DeleteManifest(ctx *context.Context) {
opts, err := getBlobSearchOptionsFromContext(ctx)
if err != nil {
apiErrorDefined(ctx, errManifestUnknown)
return
}
pvs, err := container_model.GetManifestVersions(ctx, opts)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
if len(pvs) == 0 {
apiErrorDefined(ctx, errManifestUnknown)
return
}
for _, pv := range pvs {
if err := packages_service.RemovePackageVersion(ctx, ctx.Doer, pv); err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
}
setResponseHeaders(ctx.Resp, &containerHeaders{
Status: http.StatusAccepted,
})
}
func serveBlob(ctx *context.Context, pfd *packages_model.PackageFileDescriptor) {
s, u, _, err := packages_service.GetPackageBlobStream(ctx, pfd.File, pfd.Blob)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
headers := &containerHeaders{
ContentDigest: pfd.Properties.GetByName(container_module.PropertyDigest),
ContentType: pfd.Properties.GetByName(container_module.PropertyMediaType),
ContentLength: pfd.Blob.Size,
Status: http.StatusOK,
}
if u != nil {
headers.Status = http.StatusTemporaryRedirect
headers.Location = u.String()
setResponseHeaders(ctx.Resp, headers)
return
}
defer s.Close()
setResponseHeaders(ctx.Resp, headers)
if _, err := io.Copy(ctx.Resp, s); err != nil {
log.Error("Error whilst copying content to response: %v", err)
}
}
// https://github.com/opencontainers/distribution-spec/blob/main/spec.md#content-discovery
func GetTagList(ctx *context.Context) {
image := ctx.Params("image")
if _, err := packages_model.GetPackageByName(ctx, ctx.Package.Owner.ID, packages_model.TypeContainer, image); err != nil {
if err == packages_model.ErrPackageNotExist {
apiErrorDefined(ctx, errNameUnknown)
} else {
apiError(ctx, http.StatusInternalServerError, err)
}
return
}
n := -1
if ctx.FormTrim("n") != "" {
n = ctx.FormInt("n")
}
last := ctx.FormTrim("last")
tags, err := container_model.GetImageTags(ctx, ctx.Package.Owner.ID, image, n, last)
if err != nil {
apiError(ctx, http.StatusInternalServerError, err)
return
}
type TagList struct {
Name string `json:"name"`
Tags []string `json:"tags"`
}
if len(tags) > 0 {
v := url.Values{}
if n > 0 {
v.Add("n", strconv.Itoa(n))
}
v.Add("last", tags[len(tags)-1])
ctx.Resp.Header().Set("Link", fmt.Sprintf(`</v2/%s/%s/tags/list?%s>; rel="next"`, ctx.Package.Owner.LowerName, image, v.Encode()))
}
jsonResponse(ctx, http.StatusOK, TagList{
Name: strings.ToLower(ctx.Package.Owner.LowerName + "/" + image),
Tags: tags,
})
}
// FIXME: Workaround to be removed in v1.20
// https://github.com/go-gitea/gitea/issues/19586
func workaroundGetContainerBlob(ctx *context.Context, opts *container_model.BlobSearchOptions) (*packages_model.PackageFileDescriptor, error) {
blob, err := container_model.GetContainerBlob(ctx, opts)
if err != nil {
return nil, err
}
err = packages_module.NewContentStore().Has(packages_module.BlobHash256Key(blob.Blob.HashSHA256))
if err != nil {
if errors.Is(err, util.ErrNotExist) || errors.Is(err, os.ErrNotExist) {
log.Debug("Package registry inconsistent: blob %s does not exist on file system", blob.Blob.HashSHA256)
return nil, container_model.ErrContainerBlobNotExist
}
return nil, err
}
return blob, nil
}