VictoriaMetrics/vendor/cloud.google.com/go/storage/storage.go
2023-07-07 00:04:32 -07:00

2246 lines
75 KiB
Go

// Copyright 2014 Google LLC
//
// 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 storage
import (
"bytes"
"context"
"crypto"
"crypto/rand"
"crypto/rsa"
"crypto/sha256"
"crypto/x509"
"encoding/base64"
"encoding/hex"
"encoding/pem"
"errors"
"fmt"
"net/http"
"net/url"
"os"
"reflect"
"regexp"
"sort"
"strconv"
"strings"
"time"
"unicode/utf8"
"cloud.google.com/go/internal/optional"
"cloud.google.com/go/internal/trace"
"cloud.google.com/go/storage/internal"
"cloud.google.com/go/storage/internal/apiv2/storagepb"
"github.com/googleapis/gax-go/v2"
"golang.org/x/oauth2/google"
"google.golang.org/api/googleapi"
"google.golang.org/api/option"
"google.golang.org/api/option/internaloption"
raw "google.golang.org/api/storage/v1"
"google.golang.org/api/transport"
htransport "google.golang.org/api/transport/http"
"google.golang.org/protobuf/proto"
"google.golang.org/protobuf/reflect/protoreflect"
"google.golang.org/protobuf/types/known/fieldmaskpb"
"google.golang.org/protobuf/types/known/timestamppb"
)
// Methods which can be used in signed URLs.
var signedURLMethods = map[string]bool{"DELETE": true, "GET": true, "HEAD": true, "POST": true, "PUT": true}
var (
// ErrBucketNotExist indicates that the bucket does not exist.
ErrBucketNotExist = errors.New("storage: bucket doesn't exist")
// ErrObjectNotExist indicates that the object does not exist.
ErrObjectNotExist = errors.New("storage: object doesn't exist")
// errMethodNotSupported indicates that the method called is not currently supported by the client.
// TODO: Export this error when launching the transport-agnostic client.
errMethodNotSupported = errors.New("storage: method is not currently supported")
// errMethodNotValid indicates that given HTTP method is not valid.
errMethodNotValid = fmt.Errorf("storage: HTTP method should be one of %v", reflect.ValueOf(signedURLMethods).MapKeys())
)
var userAgent = fmt.Sprintf("gcloud-golang-storage/%s", internal.Version)
const (
// ScopeFullControl grants permissions to manage your
// data and permissions in Google Cloud Storage.
ScopeFullControl = raw.DevstorageFullControlScope
// ScopeReadOnly grants permissions to
// view your data in Google Cloud Storage.
ScopeReadOnly = raw.DevstorageReadOnlyScope
// ScopeReadWrite grants permissions to manage your
// data in Google Cloud Storage.
ScopeReadWrite = raw.DevstorageReadWriteScope
// aes256Algorithm is the AES256 encryption algorithm used with the
// Customer-Supplied Encryption Keys feature.
aes256Algorithm = "AES256"
// defaultGen indicates the latest object generation by default,
// using a negative value.
defaultGen = int64(-1)
)
// TODO: remove this once header with invocation ID is applied to all methods.
func setClientHeader(headers http.Header) {
headers.Set("x-goog-api-client", xGoogDefaultHeader)
}
// Client is a client for interacting with Google Cloud Storage.
//
// Clients should be reused instead of created as needed.
// The methods of Client are safe for concurrent use by multiple goroutines.
type Client struct {
hc *http.Client
raw *raw.Service
// Scheme describes the scheme under the current host.
scheme string
// xmlHost is the default host used for XML requests.
xmlHost string
// May be nil.
creds *google.Credentials
retry *retryConfig
// tc is the transport-agnostic client implemented with either gRPC or HTTP.
tc storageClient
// useGRPC flags whether the client uses gRPC. This is needed while the
// integration piece is only partially complete.
// TODO: remove before merging to main.
useGRPC bool
}
// NewClient creates a new Google Cloud Storage client.
// The default scope is ScopeFullControl. To use a different scope, like
// ScopeReadOnly, use option.WithScopes.
//
// Clients should be reused instead of created as needed. The methods of Client
// are safe for concurrent use by multiple goroutines.
//
// You may configure the client by passing in options from the [google.golang.org/api/option]
// package. You may also use options defined in this package, such as [WithJSONReads].
func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error) {
// Use the experimental gRPC client if the env var is set.
// This is an experimental API and not intended for public use.
if withGRPC := os.Getenv("STORAGE_USE_GRPC"); withGRPC != "" {
return newGRPCClient(ctx, opts...)
}
var creds *google.Credentials
// In general, it is recommended to use raw.NewService instead of htransport.NewClient
// since raw.NewService configures the correct default endpoints when initializing the
// internal http client. However, in our case, "NewRangeReader" in reader.go needs to
// access the http client directly to make requests, so we create the client manually
// here so it can be re-used by both reader.go and raw.NewService. This means we need to
// manually configure the default endpoint options on the http client. Furthermore, we
// need to account for STORAGE_EMULATOR_HOST override when setting the default endpoints.
if host := os.Getenv("STORAGE_EMULATOR_HOST"); host == "" {
// Prepend default options to avoid overriding options passed by the user.
opts = append([]option.ClientOption{option.WithScopes(ScopeFullControl, "https://www.googleapis.com/auth/cloud-platform"), option.WithUserAgent(userAgent)}, opts...)
opts = append(opts, internaloption.WithDefaultEndpoint("https://storage.googleapis.com/storage/v1/"))
opts = append(opts, internaloption.WithDefaultMTLSEndpoint("https://storage.mtls.googleapis.com/storage/v1/"))
// Don't error out here. The user may have passed in their own HTTP
// client which does not auth with ADC or other common conventions.
c, err := transport.Creds(ctx, opts...)
if err == nil {
creds = c
opts = append(opts, internaloption.WithCredentials(creds))
}
} else {
var hostURL *url.URL
if strings.Contains(host, "://") {
h, err := url.Parse(host)
if err != nil {
return nil, err
}
hostURL = h
} else {
// Add scheme for user if not supplied in STORAGE_EMULATOR_HOST
// URL is only parsed correctly if it has a scheme, so we build it ourselves
hostURL = &url.URL{Scheme: "http", Host: host}
}
hostURL.Path = "storage/v1/"
endpoint := hostURL.String()
// Append the emulator host as default endpoint for the user
opts = append([]option.ClientOption{
option.WithoutAuthentication(),
internaloption.SkipDialSettingsValidation(),
internaloption.WithDefaultEndpoint(endpoint),
internaloption.WithDefaultMTLSEndpoint(endpoint),
}, opts...)
}
// htransport selects the correct endpoint among WithEndpoint (user override), WithDefaultEndpoint, and WithDefaultMTLSEndpoint.
hc, ep, err := htransport.NewClient(ctx, opts...)
if err != nil {
return nil, fmt.Errorf("dialing: %w", err)
}
// RawService should be created with the chosen endpoint to take account of user override.
rawService, err := raw.NewService(ctx, option.WithEndpoint(ep), option.WithHTTPClient(hc))
if err != nil {
return nil, fmt.Errorf("storage client: %w", err)
}
// Update xmlHost and scheme with the chosen endpoint.
u, err := url.Parse(ep)
if err != nil {
return nil, fmt.Errorf("supplied endpoint %q is not valid: %w", ep, err)
}
tc, err := newHTTPStorageClient(ctx, withClientOptions(opts...))
if err != nil {
return nil, fmt.Errorf("storage: %w", err)
}
return &Client{
hc: hc,
raw: rawService,
scheme: u.Scheme,
xmlHost: u.Host,
creds: creds,
tc: tc,
}, nil
}
// newGRPCClient creates a new Storage client that initializes a gRPC-based
// client. Calls that have not been implemented in gRPC will panic.
//
// This is an experimental API and not intended for public use.
func newGRPCClient(ctx context.Context, opts ...option.ClientOption) (*Client, error) {
opts = append(defaultGRPCOptions(), opts...)
tc, err := newGRPCStorageClient(ctx, withClientOptions(opts...))
if err != nil {
return nil, err
}
return &Client{tc: tc, useGRPC: true}, nil
}
// Close closes the Client.
//
// Close need not be called at program exit.
func (c *Client) Close() error {
// Set fields to nil so that subsequent uses will panic.
c.hc = nil
c.raw = nil
c.creds = nil
if c.tc != nil {
return c.tc.Close()
}
return nil
}
// SigningScheme determines the API version to use when signing URLs.
type SigningScheme int
const (
// SigningSchemeDefault is presently V2 and will change to V4 in the future.
SigningSchemeDefault SigningScheme = iota
// SigningSchemeV2 uses the V2 scheme to sign URLs.
SigningSchemeV2
// SigningSchemeV4 uses the V4 scheme to sign URLs.
SigningSchemeV4
)
// URLStyle determines the style to use for the signed URL. PathStyle is the
// default. All non-default options work with V4 scheme only. See
// https://cloud.google.com/storage/docs/request-endpoints for details.
type URLStyle interface {
// host should return the host portion of the signed URL, not including
// the scheme (e.g. storage.googleapis.com).
host(hostname, bucket string) string
// path should return the path portion of the signed URL, which may include
// both the bucket and object name or only the object name depending on the
// style.
path(bucket, object string) string
}
type pathStyle struct{}
type virtualHostedStyle struct{}
type bucketBoundHostname struct {
hostname string
}
func (s pathStyle) host(hostname, bucket string) string {
if hostname != "" {
return stripScheme(hostname)
}
if host := os.Getenv("STORAGE_EMULATOR_HOST"); host != "" {
return stripScheme(host)
}
return "storage.googleapis.com"
}
func (s virtualHostedStyle) host(_, bucket string) string {
if host := os.Getenv("STORAGE_EMULATOR_HOST"); host != "" {
return bucket + "." + stripScheme(host)
}
return bucket + ".storage.googleapis.com"
}
func (s bucketBoundHostname) host(_, bucket string) string {
return s.hostname
}
func (s pathStyle) path(bucket, object string) string {
p := bucket
if object != "" {
p += "/" + object
}
return p
}
func (s virtualHostedStyle) path(bucket, object string) string {
return object
}
func (s bucketBoundHostname) path(bucket, object string) string {
return object
}
// PathStyle is the default style, and will generate a URL of the form
// "<host-name>/<bucket-name>/<object-name>". By default, <host-name> is
// storage.googleapis.com, but setting an endpoint on the storage Client or
// through STORAGE_EMULATOR_HOST overrides this. Setting Hostname on
// SignedURLOptions or PostPolicyV4Options overrides everything else.
func PathStyle() URLStyle {
return pathStyle{}
}
// VirtualHostedStyle generates a URL relative to the bucket's virtual
// hostname, e.g. "<bucket-name>.storage.googleapis.com/<object-name>".
func VirtualHostedStyle() URLStyle {
return virtualHostedStyle{}
}
// BucketBoundHostname generates a URL with a custom hostname tied to a
// specific GCS bucket. The desired hostname should be passed in using the
// hostname argument. Generated urls will be of the form
// "<bucket-bound-hostname>/<object-name>". See
// https://cloud.google.com/storage/docs/request-endpoints#cname and
// https://cloud.google.com/load-balancing/docs/https/adding-backend-buckets-to-load-balancers
// for details. Note that for CNAMEs, only HTTP is supported, so Insecure must
// be set to true.
func BucketBoundHostname(hostname string) URLStyle {
return bucketBoundHostname{hostname: hostname}
}
// Strips the scheme from a host if it contains it
func stripScheme(host string) string {
if strings.Contains(host, "://") {
host = strings.SplitN(host, "://", 2)[1]
}
return host
}
// SignedURLOptions allows you to restrict the access to the signed URL.
type SignedURLOptions struct {
// GoogleAccessID represents the authorizer of the signed URL generation.
// It is typically the Google service account client email address from
// the Google Developers Console in the form of "xxx@developer.gserviceaccount.com".
// Required.
GoogleAccessID string
// PrivateKey is the Google service account private key. It is obtainable
// from the Google Developers Console.
// At https://console.developers.google.com/project/<your-project-id>/apiui/credential,
// create a service account client ID or reuse one of your existing service account
// credentials. Click on the "Generate new P12 key" to generate and download
// a new private key. Once you download the P12 file, use the following command
// to convert it into a PEM file.
//
// $ openssl pkcs12 -in key.p12 -passin pass:notasecret -out key.pem -nodes
//
// Provide the contents of the PEM file as a byte slice.
// Exactly one of PrivateKey or SignBytes must be non-nil.
PrivateKey []byte
// SignBytes is a function for implementing custom signing. For example, if
// your application is running on Google App Engine, you can use
// appengine's internal signing function:
// ctx := appengine.NewContext(request)
// acc, _ := appengine.ServiceAccount(ctx)
// url, err := SignedURL("bucket", "object", &SignedURLOptions{
// GoogleAccessID: acc,
// SignBytes: func(b []byte) ([]byte, error) {
// _, signedBytes, err := appengine.SignBytes(ctx, b)
// return signedBytes, err
// },
// // etc.
// })
//
// Exactly one of PrivateKey or SignBytes must be non-nil.
SignBytes func([]byte) ([]byte, error)
// Method is the HTTP method to be used with the signed URL.
// Signed URLs can be used with GET, HEAD, PUT, and DELETE requests.
// Required.
Method string
// Expires is the expiration time on the signed URL. It must be
// a datetime in the future. For SigningSchemeV4, the expiration may be no
// more than seven days in the future.
// Required.
Expires time.Time
// ContentType is the content type header the client must provide
// to use the generated signed URL.
// Optional.
ContentType string
// Headers is a list of extension headers the client must provide
// in order to use the generated signed URL. Each must be a string of the
// form "key:values", with multiple values separated by a semicolon.
// Optional.
Headers []string
// QueryParameters is a map of additional query parameters. When
// SigningScheme is V4, this is used in computing the signature, and the
// client must use the same query parameters when using the generated signed
// URL.
// Optional.
QueryParameters url.Values
// MD5 is the base64 encoded MD5 checksum of the file.
// If provided, the client should provide the exact value on the request
// header in order to use the signed URL.
// Optional.
MD5 string
// Style provides options for the type of URL to use. Options are
// PathStyle (default), BucketBoundHostname, and VirtualHostedStyle. See
// https://cloud.google.com/storage/docs/request-endpoints for details.
// Only supported for V4 signing.
// Optional.
Style URLStyle
// Insecure determines whether the signed URL should use HTTPS (default) or
// HTTP.
// Only supported for V4 signing.
// Optional.
Insecure bool
// Scheme determines the version of URL signing to use. Default is
// SigningSchemeV2.
Scheme SigningScheme
// Hostname sets the host of the signed URL. This field overrides any
// endpoint set on a storage Client or through STORAGE_EMULATOR_HOST.
// Only compatible with PathStyle URLStyle.
// Optional.
Hostname string
}
func (opts *SignedURLOptions) clone() *SignedURLOptions {
return &SignedURLOptions{
GoogleAccessID: opts.GoogleAccessID,
SignBytes: opts.SignBytes,
PrivateKey: opts.PrivateKey,
Method: opts.Method,
Expires: opts.Expires,
ContentType: opts.ContentType,
Headers: opts.Headers,
QueryParameters: opts.QueryParameters,
MD5: opts.MD5,
Style: opts.Style,
Insecure: opts.Insecure,
Scheme: opts.Scheme,
Hostname: opts.Hostname,
}
}
var (
tabRegex = regexp.MustCompile(`[\t]+`)
// I was tempted to call this spacex. :)
spaceRegex = regexp.MustCompile(` +`)
canonicalHeaderRegexp = regexp.MustCompile(`(?i)^(x-goog-[^:]+):(.*)?$`)
excludedCanonicalHeaders = map[string]bool{
"x-goog-encryption-key": true,
"x-goog-encryption-key-sha256": true,
}
)
// v2SanitizeHeaders applies the specifications for canonical extension headers at
// https://cloud.google.com/storage/docs/access-control/signed-urls-v2#about-canonical-extension-headers
func v2SanitizeHeaders(hdrs []string) []string {
headerMap := map[string][]string{}
for _, hdr := range hdrs {
// No leading or trailing whitespaces.
sanitizedHeader := strings.TrimSpace(hdr)
var header, value string
// Only keep canonical headers, discard any others.
headerMatches := canonicalHeaderRegexp.FindStringSubmatch(sanitizedHeader)
if len(headerMatches) == 0 {
continue
}
header = headerMatches[1]
value = headerMatches[2]
header = strings.ToLower(strings.TrimSpace(header))
value = strings.TrimSpace(value)
if excludedCanonicalHeaders[header] {
// Do not keep any deliberately excluded canonical headers when signing.
continue
}
if len(value) > 0 {
// Remove duplicate headers by appending the values of duplicates
// in their order of appearance.
headerMap[header] = append(headerMap[header], value)
}
}
var sanitizedHeaders []string
for header, values := range headerMap {
// There should be no spaces around the colon separating the header name
// from the header value or around the values themselves. The values
// should be separated by commas.
//
// NOTE: The semantics for headers without a value are not clear.
// However from specifications these should be edge-cases anyway and we
// should assume that there will be no canonical headers using empty
// values. Any such headers are discarded at the regexp stage above.
sanitizedHeaders = append(sanitizedHeaders, fmt.Sprintf("%s:%s", header, strings.Join(values, ",")))
}
sort.Strings(sanitizedHeaders)
return sanitizedHeaders
}
// v4SanitizeHeaders applies the specifications for canonical extension headers
// at https://cloud.google.com/storage/docs/authentication/canonical-requests#about-headers.
//
// V4 does a couple things differently from V2:
// - Headers get sorted by key, instead of by key:value. We do this in
// signedURLV4.
// - There's no canonical regexp: we simply split headers on :.
// - We don't exclude canonical headers.
// - We replace leading and trailing spaces in header values, like v2, but also
// all intermediate space duplicates get stripped. That is, there's only ever
// a single consecutive space.
func v4SanitizeHeaders(hdrs []string) []string {
headerMap := map[string][]string{}
for _, hdr := range hdrs {
// No leading or trailing whitespaces.
sanitizedHeader := strings.TrimSpace(hdr)
var key, value string
headerMatches := strings.SplitN(sanitizedHeader, ":", 2)
if len(headerMatches) < 2 {
continue
}
key = headerMatches[0]
value = headerMatches[1]
key = strings.ToLower(strings.TrimSpace(key))
value = strings.TrimSpace(value)
value = string(spaceRegex.ReplaceAll([]byte(value), []byte(" ")))
value = string(tabRegex.ReplaceAll([]byte(value), []byte("\t")))
if len(value) > 0 {
// Remove duplicate headers by appending the values of duplicates
// in their order of appearance.
headerMap[key] = append(headerMap[key], value)
}
}
var sanitizedHeaders []string
for header, values := range headerMap {
// There should be no spaces around the colon separating the header name
// from the header value or around the values themselves. The values
// should be separated by commas.
//
// NOTE: The semantics for headers without a value are not clear.
// However from specifications these should be edge-cases anyway and we
// should assume that there will be no canonical headers using empty
// values. Any such headers are discarded at the regexp stage above.
sanitizedHeaders = append(sanitizedHeaders, fmt.Sprintf("%s:%s", header, strings.Join(values, ",")))
}
return sanitizedHeaders
}
// SignedURL returns a URL for the specified object. Signed URLs allow anyone
// access to a restricted resource for a limited time without needing a
// Google account or signing in. For more information about signed URLs, see
// https://cloud.google.com/storage/docs/accesscontrol#signed_urls_query_string_authentication
// If initializing a Storage Client, instead use the Bucket.SignedURL method
// which uses the Client's credentials to handle authentication.
func SignedURL(bucket, object string, opts *SignedURLOptions) (string, error) {
now := utcNow()
if err := validateOptions(opts, now); err != nil {
return "", err
}
switch opts.Scheme {
case SigningSchemeV2:
opts.Headers = v2SanitizeHeaders(opts.Headers)
return signedURLV2(bucket, object, opts)
case SigningSchemeV4:
opts.Headers = v4SanitizeHeaders(opts.Headers)
return signedURLV4(bucket, object, opts, now)
default: // SigningSchemeDefault
opts.Headers = v2SanitizeHeaders(opts.Headers)
return signedURLV2(bucket, object, opts)
}
}
func validateOptions(opts *SignedURLOptions, now time.Time) error {
if opts == nil {
return errors.New("storage: missing required SignedURLOptions")
}
if opts.GoogleAccessID == "" {
return errors.New("storage: missing required GoogleAccessID")
}
if (opts.PrivateKey == nil) == (opts.SignBytes == nil) {
return errors.New("storage: exactly one of PrivateKey or SignedBytes must be set")
}
opts.Method = strings.ToUpper(opts.Method)
if _, ok := signedURLMethods[opts.Method]; !ok {
return errMethodNotValid
}
if opts.Expires.IsZero() {
return errors.New("storage: missing required expires option")
}
if opts.MD5 != "" {
md5, err := base64.StdEncoding.DecodeString(opts.MD5)
if err != nil || len(md5) != 16 {
return errors.New("storage: invalid MD5 checksum")
}
}
if opts.Style == nil {
opts.Style = PathStyle()
}
if _, ok := opts.Style.(pathStyle); !ok && opts.Scheme == SigningSchemeV2 {
return errors.New("storage: only path-style URLs are permitted with SigningSchemeV2")
}
if opts.Scheme == SigningSchemeV4 {
cutoff := now.Add(604801 * time.Second) // 7 days + 1 second
if !opts.Expires.Before(cutoff) {
return errors.New("storage: expires must be within seven days from now")
}
}
return nil
}
const (
iso8601 = "20060102T150405Z"
yearMonthDay = "20060102"
)
// utcNow returns the current time in UTC and is a variable to allow for
// reassignment in tests to provide deterministic signed URL values.
var utcNow = func() time.Time {
return time.Now().UTC()
}
// extractHeaderNames takes in a series of key:value headers and returns the
// header names only.
func extractHeaderNames(kvs []string) []string {
var res []string
for _, header := range kvs {
nameValue := strings.SplitN(header, ":", 2)
res = append(res, nameValue[0])
}
return res
}
// pathEncodeV4 creates an encoded string that matches the v4 signature spec.
// Following the spec precisely is necessary in order to ensure that the URL
// and signing string are correctly formed, and Go's url.PathEncode and
// url.QueryEncode don't generate an exact match without some additional logic.
func pathEncodeV4(path string) string {
segments := strings.Split(path, "/")
var encodedSegments []string
for _, s := range segments {
encodedSegments = append(encodedSegments, url.QueryEscape(s))
}
encodedStr := strings.Join(encodedSegments, "/")
encodedStr = strings.Replace(encodedStr, "+", "%20", -1)
return encodedStr
}
// signedURLV4 creates a signed URL using the sigV4 algorithm.
func signedURLV4(bucket, name string, opts *SignedURLOptions, now time.Time) (string, error) {
buf := &bytes.Buffer{}
fmt.Fprintf(buf, "%s\n", opts.Method)
u := &url.URL{Path: opts.Style.path(bucket, name)}
u.RawPath = pathEncodeV4(u.Path)
// Note: we have to add a / here because GCS does so auto-magically, despite
// our encoding not doing so (and we have to exactly match their
// canonical query).
fmt.Fprintf(buf, "/%s\n", u.RawPath)
headerNames := append(extractHeaderNames(opts.Headers), "host")
if opts.ContentType != "" {
headerNames = append(headerNames, "content-type")
}
if opts.MD5 != "" {
headerNames = append(headerNames, "content-md5")
}
sort.Strings(headerNames)
signedHeaders := strings.Join(headerNames, ";")
timestamp := now.Format(iso8601)
credentialScope := fmt.Sprintf("%s/auto/storage/goog4_request", now.Format(yearMonthDay))
canonicalQueryString := url.Values{
"X-Goog-Algorithm": {"GOOG4-RSA-SHA256"},
"X-Goog-Credential": {fmt.Sprintf("%s/%s", opts.GoogleAccessID, credentialScope)},
"X-Goog-Date": {timestamp},
"X-Goog-Expires": {fmt.Sprintf("%d", int(opts.Expires.Sub(now).Seconds()))},
"X-Goog-SignedHeaders": {signedHeaders},
}
// Add user-supplied query parameters to the canonical query string. For V4,
// it's necessary to include these.
for k, v := range opts.QueryParameters {
canonicalQueryString[k] = append(canonicalQueryString[k], v...)
}
// url.Values.Encode escaping is correct, except that a space must be replaced
// by `%20` rather than `+`.
escapedQuery := strings.Replace(canonicalQueryString.Encode(), "+", "%20", -1)
fmt.Fprintf(buf, "%s\n", escapedQuery)
// Fill in the hostname based on the desired URL style.
u.Host = opts.Style.host(opts.Hostname, bucket)
// Fill in the URL scheme.
if opts.Insecure {
u.Scheme = "http"
} else {
u.Scheme = "https"
}
var headersWithValue []string
headersWithValue = append(headersWithValue, "host:"+u.Host)
headersWithValue = append(headersWithValue, opts.Headers...)
if opts.ContentType != "" {
headersWithValue = append(headersWithValue, "content-type:"+opts.ContentType)
}
if opts.MD5 != "" {
headersWithValue = append(headersWithValue, "content-md5:"+opts.MD5)
}
// Trim extra whitespace from headers and replace with a single space.
var trimmedHeaders []string
for _, h := range headersWithValue {
trimmedHeaders = append(trimmedHeaders, strings.Join(strings.Fields(h), " "))
}
canonicalHeaders := strings.Join(sortHeadersByKey(trimmedHeaders), "\n")
fmt.Fprintf(buf, "%s\n\n", canonicalHeaders)
fmt.Fprintf(buf, "%s\n", signedHeaders)
// If the user provides a value for X-Goog-Content-SHA256, we must use
// that value in the request string. If not, we use UNSIGNED-PAYLOAD.
sha256Header := false
for _, h := range trimmedHeaders {
if strings.HasPrefix(strings.ToLower(h), "x-goog-content-sha256") && strings.Contains(h, ":") {
sha256Header = true
fmt.Fprintf(buf, "%s", strings.SplitN(h, ":", 2)[1])
break
}
}
if !sha256Header {
fmt.Fprint(buf, "UNSIGNED-PAYLOAD")
}
sum := sha256.Sum256(buf.Bytes())
hexDigest := hex.EncodeToString(sum[:])
signBuf := &bytes.Buffer{}
fmt.Fprint(signBuf, "GOOG4-RSA-SHA256\n")
fmt.Fprintf(signBuf, "%s\n", timestamp)
fmt.Fprintf(signBuf, "%s\n", credentialScope)
fmt.Fprintf(signBuf, "%s", hexDigest)
signBytes := opts.SignBytes
if opts.PrivateKey != nil {
key, err := parseKey(opts.PrivateKey)
if err != nil {
return "", err
}
signBytes = func(b []byte) ([]byte, error) {
sum := sha256.Sum256(b)
return rsa.SignPKCS1v15(
rand.Reader,
key,
crypto.SHA256,
sum[:],
)
}
}
b, err := signBytes(signBuf.Bytes())
if err != nil {
return "", err
}
signature := hex.EncodeToString(b)
canonicalQueryString.Set("X-Goog-Signature", string(signature))
u.RawQuery = canonicalQueryString.Encode()
return u.String(), nil
}
// takes a list of headerKey:headervalue1,headervalue2,etc and sorts by header
// key.
func sortHeadersByKey(hdrs []string) []string {
headersMap := map[string]string{}
var headersKeys []string
for _, h := range hdrs {
parts := strings.SplitN(h, ":", 2)
k := parts[0]
v := parts[1]
headersMap[k] = v
headersKeys = append(headersKeys, k)
}
sort.Strings(headersKeys)
var sorted []string
for _, k := range headersKeys {
v := headersMap[k]
sorted = append(sorted, fmt.Sprintf("%s:%s", k, v))
}
return sorted
}
func signedURLV2(bucket, name string, opts *SignedURLOptions) (string, error) {
signBytes := opts.SignBytes
if opts.PrivateKey != nil {
key, err := parseKey(opts.PrivateKey)
if err != nil {
return "", err
}
signBytes = func(b []byte) ([]byte, error) {
sum := sha256.Sum256(b)
return rsa.SignPKCS1v15(
rand.Reader,
key,
crypto.SHA256,
sum[:],
)
}
}
u := &url.URL{
Path: fmt.Sprintf("/%s/%s", bucket, name),
}
buf := &bytes.Buffer{}
fmt.Fprintf(buf, "%s\n", opts.Method)
fmt.Fprintf(buf, "%s\n", opts.MD5)
fmt.Fprintf(buf, "%s\n", opts.ContentType)
fmt.Fprintf(buf, "%d\n", opts.Expires.Unix())
if len(opts.Headers) > 0 {
fmt.Fprintf(buf, "%s\n", strings.Join(opts.Headers, "\n"))
}
fmt.Fprintf(buf, "%s", u.String())
b, err := signBytes(buf.Bytes())
if err != nil {
return "", err
}
encoded := base64.StdEncoding.EncodeToString(b)
u.Scheme = "https"
u.Host = PathStyle().host(opts.Hostname, bucket)
q := u.Query()
q.Set("GoogleAccessId", opts.GoogleAccessID)
q.Set("Expires", fmt.Sprintf("%d", opts.Expires.Unix()))
q.Set("Signature", string(encoded))
u.RawQuery = q.Encode()
return u.String(), nil
}
// ObjectHandle provides operations on an object in a Google Cloud Storage bucket.
// Use BucketHandle.Object to get a handle.
type ObjectHandle struct {
c *Client
bucket string
object string
acl ACLHandle
gen int64 // a negative value indicates latest
conds *Conditions
encryptionKey []byte // AES-256 key
userProject string // for requester-pays buckets
readCompressed bool // Accept-Encoding: gzip
retry *retryConfig
}
// ACL provides access to the object's access control list.
// This controls who can read and write this object.
// This call does not perform any network operations.
func (o *ObjectHandle) ACL() *ACLHandle {
return &o.acl
}
// Generation returns a new ObjectHandle that operates on a specific generation
// of the object.
// By default, the handle operates on the latest generation. Not
// all operations work when given a specific generation; check the API
// endpoints at https://cloud.google.com/storage/docs/json_api/ for details.
func (o *ObjectHandle) Generation(gen int64) *ObjectHandle {
o2 := *o
o2.gen = gen
return &o2
}
// If returns a new ObjectHandle that applies a set of preconditions.
// Preconditions already set on the ObjectHandle are ignored. The supplied
// Conditions must have at least one field set to a non-default value;
// otherwise an error will be returned from any operation on the ObjectHandle.
// Operations on the new handle will return an error if the preconditions are not
// satisfied. See https://cloud.google.com/storage/docs/generations-preconditions
// for more details.
func (o *ObjectHandle) If(conds Conditions) *ObjectHandle {
o2 := *o
o2.conds = &conds
return &o2
}
// Key returns a new ObjectHandle that uses the supplied encryption
// key to encrypt and decrypt the object's contents.
//
// Encryption key must be a 32-byte AES-256 key.
// See https://cloud.google.com/storage/docs/encryption for details.
func (o *ObjectHandle) Key(encryptionKey []byte) *ObjectHandle {
o2 := *o
o2.encryptionKey = encryptionKey
return &o2
}
// Attrs returns meta information about the object.
// ErrObjectNotExist will be returned if the object is not found.
func (o *ObjectHandle) Attrs(ctx context.Context) (attrs *ObjectAttrs, err error) {
ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.Object.Attrs")
defer func() { trace.EndSpan(ctx, err) }()
if err := o.validate(); err != nil {
return nil, err
}
opts := makeStorageOpts(true, o.retry, o.userProject)
return o.c.tc.GetObject(ctx, o.bucket, o.object, o.gen, o.encryptionKey, o.conds, opts...)
}
// Update updates an object with the provided attributes. See
// ObjectAttrsToUpdate docs for details on treatment of zero values.
// ErrObjectNotExist will be returned if the object is not found.
func (o *ObjectHandle) Update(ctx context.Context, uattrs ObjectAttrsToUpdate) (oa *ObjectAttrs, err error) {
ctx = trace.StartSpan(ctx, "cloud.google.com/go/storage.Object.Update")
defer func() { trace.EndSpan(ctx, err) }()
if err := o.validate(); err != nil {
return nil, err
}
isIdempotent := o.conds != nil && o.conds.MetagenerationMatch != 0
opts := makeStorageOpts(isIdempotent, o.retry, o.userProject)
return o.c.tc.UpdateObject(ctx, o.bucket, o.object, &uattrs, o.gen, o.encryptionKey, o.conds, opts...)
}
// BucketName returns the name of the bucket.
func (o *ObjectHandle) BucketName() string {
return o.bucket
}
// ObjectName returns the name of the object.
func (o *ObjectHandle) ObjectName() string {
return o.object
}
// ObjectAttrsToUpdate is used to update the attributes of an object.
// Only fields set to non-nil values will be updated.
// For all fields except CustomTime, set the field to its zero value to delete
// it. CustomTime cannot be deleted or changed to an earlier time once set.
//
// For example, to change ContentType and delete ContentEncoding and
// Metadata, use
//
// ObjectAttrsToUpdate{
// ContentType: "text/html",
// ContentEncoding: "",
// Metadata: map[string]string{},
// }
type ObjectAttrsToUpdate struct {
EventBasedHold optional.Bool
TemporaryHold optional.Bool
ContentType optional.String
ContentLanguage optional.String
ContentEncoding optional.String
ContentDisposition optional.String
CacheControl optional.String
CustomTime time.Time // Cannot be deleted or backdated from its current value.
Metadata map[string]string // Set to map[string]string{} to delete.
ACL []ACLRule
// If not empty, applies a predefined set of access controls. ACL must be nil.
// See https://cloud.google.com/storage/docs/json_api/v1/objects/patch.
PredefinedACL string
}
// Delete deletes the single specified object.
func (o *ObjectHandle) Delete(ctx context.Context) error {
if err := o.validate(); err != nil {
return err
}
// Delete is idempotent if GenerationMatch or Generation have been passed in.
// The default generation is negative to get the latest version of the object.
isIdempotent := (o.conds != nil && o.conds.GenerationMatch != 0) || o.gen >= 0
opts := makeStorageOpts(isIdempotent, o.retry, o.userProject)
return o.c.tc.DeleteObject(ctx, o.bucket, o.object, o.gen, o.conds, opts...)
}
// ReadCompressed when true causes the read to happen without decompressing.
func (o *ObjectHandle) ReadCompressed(compressed bool) *ObjectHandle {
o2 := *o
o2.readCompressed = compressed
return &o2
}
// NewWriter returns a storage Writer that writes to the GCS object
// associated with this ObjectHandle.
//
// A new object will be created unless an object with this name already exists.
// Otherwise any previous object with the same name will be replaced.
// The object will not be available (and any previous object will remain)
// until Close has been called.
//
// Attributes can be set on the object by modifying the returned Writer's
// ObjectAttrs field before the first call to Write. If no ContentType
// attribute is specified, the content type will be automatically sniffed
// using net/http.DetectContentType.
//
// Note that each Writer allocates an internal buffer of size Writer.ChunkSize.
// See the ChunkSize docs for more information.
//
// It is the caller's responsibility to call Close when writing is done. To
// stop writing without saving the data, cancel the context.
func (o *ObjectHandle) NewWriter(ctx context.Context) *Writer {
return &Writer{
ctx: ctx,
o: o,
donec: make(chan struct{}),
ObjectAttrs: ObjectAttrs{Name: o.object},
ChunkSize: googleapi.DefaultUploadChunkSize,
}
}
func (o *ObjectHandle) validate() error {
if o.bucket == "" {
return errors.New("storage: bucket name is empty")
}
if o.object == "" {
return errors.New("storage: object name is empty")
}
if !utf8.ValidString(o.object) {
return fmt.Errorf("storage: object name %q is not valid UTF-8", o.object)
}
return nil
}
// parseKey converts the binary contents of a private key file to an
// *rsa.PrivateKey. It detects whether the private key is in a PEM container or
// not. If so, it extracts the private key from PEM container before
// conversion. It only supports PEM containers with no passphrase.
func parseKey(key []byte) (*rsa.PrivateKey, error) {
if block, _ := pem.Decode(key); block != nil {
key = block.Bytes
}
parsedKey, err := x509.ParsePKCS8PrivateKey(key)
if err != nil {
parsedKey, err = x509.ParsePKCS1PrivateKey(key)
if err != nil {
return nil, err
}
}
parsed, ok := parsedKey.(*rsa.PrivateKey)
if !ok {
return nil, errors.New("oauth2: private key is invalid")
}
return parsed, nil
}
// toRawObject copies the editable attributes from o to the raw library's Object type.
func (o *ObjectAttrs) toRawObject(bucket string) *raw.Object {
var ret string
if !o.RetentionExpirationTime.IsZero() {
ret = o.RetentionExpirationTime.Format(time.RFC3339)
}
var ct string
if !o.CustomTime.IsZero() {
ct = o.CustomTime.Format(time.RFC3339)
}
return &raw.Object{
Bucket: bucket,
Name: o.Name,
EventBasedHold: o.EventBasedHold,
TemporaryHold: o.TemporaryHold,
RetentionExpirationTime: ret,
ContentType: o.ContentType,
ContentEncoding: o.ContentEncoding,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
ContentDisposition: o.ContentDisposition,
StorageClass: o.StorageClass,
Acl: toRawObjectACL(o.ACL),
Metadata: o.Metadata,
CustomTime: ct,
}
}
// toProtoObject copies the editable attributes from o to the proto library's Object type.
func (o *ObjectAttrs) toProtoObject(b string) *storagepb.Object {
// For now, there are only globally unique buckets, and "_" is the alias
// project ID for such buckets. If the bucket is not provided, like in the
// destination ObjectAttrs of a Copy, do not attempt to format it.
if b != "" {
b = bucketResourceName(globalProjectAlias, b)
}
return &storagepb.Object{
Bucket: b,
Name: o.Name,
EventBasedHold: proto.Bool(o.EventBasedHold),
TemporaryHold: o.TemporaryHold,
ContentType: o.ContentType,
ContentEncoding: o.ContentEncoding,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
ContentDisposition: o.ContentDisposition,
StorageClass: o.StorageClass,
Acl: toProtoObjectACL(o.ACL),
Metadata: o.Metadata,
CreateTime: toProtoTimestamp(o.Created),
CustomTime: toProtoTimestamp(o.CustomTime),
DeleteTime: toProtoTimestamp(o.Deleted),
RetentionExpireTime: toProtoTimestamp(o.RetentionExpirationTime),
UpdateTime: toProtoTimestamp(o.Updated),
KmsKey: o.KMSKeyName,
Generation: o.Generation,
Size: o.Size,
}
}
// toProtoObject copies the attributes to update from uattrs to the proto library's Object type.
func (uattrs *ObjectAttrsToUpdate) toProtoObject(bucket, object string) *storagepb.Object {
o := &storagepb.Object{
Name: object,
Bucket: bucket,
}
if uattrs == nil {
return o
}
if uattrs.EventBasedHold != nil {
o.EventBasedHold = proto.Bool(optional.ToBool(uattrs.EventBasedHold))
}
if uattrs.TemporaryHold != nil {
o.TemporaryHold = optional.ToBool(uattrs.TemporaryHold)
}
if uattrs.ContentType != nil {
o.ContentType = optional.ToString(uattrs.ContentType)
}
if uattrs.ContentLanguage != nil {
o.ContentLanguage = optional.ToString(uattrs.ContentLanguage)
}
if uattrs.ContentEncoding != nil {
o.ContentEncoding = optional.ToString(uattrs.ContentEncoding)
}
if uattrs.ContentDisposition != nil {
o.ContentDisposition = optional.ToString(uattrs.ContentDisposition)
}
if uattrs.CacheControl != nil {
o.CacheControl = optional.ToString(uattrs.CacheControl)
}
if !uattrs.CustomTime.IsZero() {
o.CustomTime = toProtoTimestamp(uattrs.CustomTime)
}
if uattrs.ACL != nil {
o.Acl = toProtoObjectACL(uattrs.ACL)
}
o.Metadata = uattrs.Metadata
return o
}
// ObjectAttrs represents the metadata for a Google Cloud Storage (GCS) object.
type ObjectAttrs struct {
// Bucket is the name of the bucket containing this GCS object.
// This field is read-only.
Bucket string
// Name is the name of the object within the bucket.
// This field is read-only.
Name string
// ContentType is the MIME type of the object's content.
ContentType string
// ContentLanguage is the content language of the object's content.
ContentLanguage string
// CacheControl is the Cache-Control header to be sent in the response
// headers when serving the object data.
CacheControl string
// EventBasedHold specifies whether an object is under event-based hold. New
// objects created in a bucket whose DefaultEventBasedHold is set will
// default to that value.
EventBasedHold bool
// TemporaryHold specifies whether an object is under temporary hold. While
// this flag is set to true, the object is protected against deletion and
// overwrites.
TemporaryHold bool
// RetentionExpirationTime is a server-determined value that specifies the
// earliest time that the object's retention period expires.
// This is a read-only field.
RetentionExpirationTime time.Time
// ACL is the list of access control rules for the object.
ACL []ACLRule
// If not empty, applies a predefined set of access controls. It should be set
// only when writing, copying or composing an object. When copying or composing,
// it acts as the destinationPredefinedAcl parameter.
// PredefinedACL is always empty for ObjectAttrs returned from the service.
// See https://cloud.google.com/storage/docs/json_api/v1/objects/insert
// for valid values.
PredefinedACL string
// Owner is the owner of the object. This field is read-only.
//
// If non-zero, it is in the form of "user-<userId>".
Owner string
// Size is the length of the object's content. This field is read-only.
Size int64
// ContentEncoding is the encoding of the object's content.
ContentEncoding string
// ContentDisposition is the optional Content-Disposition header of the object
// sent in the response headers.
ContentDisposition string
// MD5 is the MD5 hash of the object's content. This field is read-only,
// except when used from a Writer. If set on a Writer, the uploaded
// data is rejected if its MD5 hash does not match this field.
MD5 []byte
// CRC32C is the CRC32 checksum of the object's content using the Castagnoli93
// polynomial. This field is read-only, except when used from a Writer or
// Composer. In those cases, if the SendCRC32C field in the Writer or Composer
// is set to is true, the uploaded data is rejected if its CRC32C hash does
// not match this field.
//
// Note: For a Writer, SendCRC32C must be set to true BEFORE the first call to
// Writer.Write() in order to send the checksum.
CRC32C uint32
// MediaLink is an URL to the object's content. This field is read-only.
MediaLink string
// Metadata represents user-provided metadata, in key/value pairs.
// It can be nil if no metadata is provided.
//
// For object downloads using Reader, metadata keys are sent as headers.
// Therefore, avoid setting metadata keys using characters that are not valid
// for headers. See https://www.rfc-editor.org/rfc/rfc7230#section-3.2.6.
Metadata map[string]string
// Generation is the generation number of the object's content.
// This field is read-only.
Generation int64
// Metageneration is the version of the metadata for this
// object at this generation. This field is used for preconditions
// and for detecting changes in metadata. A metageneration number
// is only meaningful in the context of a particular generation
// of a particular object. This field is read-only.
Metageneration int64
// StorageClass is the storage class of the object. This defines
// how objects are stored and determines the SLA and the cost of storage.
// Typical values are "STANDARD", "NEARLINE", "COLDLINE" and "ARCHIVE".
// Defaults to "STANDARD".
// See https://cloud.google.com/storage/docs/storage-classes for all
// valid values.
StorageClass string
// Created is the time the object was created. This field is read-only.
Created time.Time
// Deleted is the time the object was deleted.
// If not deleted, it is the zero value. This field is read-only.
Deleted time.Time
// Updated is the creation or modification time of the object.
// For buckets with versioning enabled, changing an object's
// metadata does not change this property. This field is read-only.
Updated time.Time
// CustomerKeySHA256 is the base64-encoded SHA-256 hash of the
// customer-supplied encryption key for the object. It is empty if there is
// no customer-supplied encryption key.
// See // https://cloud.google.com/storage/docs/encryption for more about
// encryption in Google Cloud Storage.
CustomerKeySHA256 string
// Cloud KMS key name, in the form
// projects/P/locations/L/keyRings/R/cryptoKeys/K, used to encrypt this object,
// if the object is encrypted by such a key.
//
// Providing both a KMSKeyName and a customer-supplied encryption key (via
// ObjectHandle.Key) will result in an error when writing an object.
KMSKeyName string
// Prefix is set only for ObjectAttrs which represent synthetic "directory
// entries" when iterating over buckets using Query.Delimiter. See
// ObjectIterator.Next. When set, no other fields in ObjectAttrs will be
// populated.
Prefix string
// Etag is the HTTP/1.1 Entity tag for the object.
// This field is read-only.
Etag string
// A user-specified timestamp which can be applied to an object. This is
// typically set in order to use the CustomTimeBefore and DaysSinceCustomTime
// LifecycleConditions to manage object lifecycles.
//
// CustomTime cannot be removed once set on an object. It can be updated to a
// later value but not to an earlier one. For more information see
// https://cloud.google.com/storage/docs/metadata#custom-time .
CustomTime time.Time
// ComponentCount is the number of objects contained within a composite object.
// For non-composite objects, the value will be zero.
// This field is read-only.
ComponentCount int64
}
// convertTime converts a time in RFC3339 format to time.Time.
// If any error occurs in parsing, the zero-value time.Time is silently returned.
func convertTime(t string) time.Time {
var r time.Time
if t != "" {
r, _ = time.Parse(time.RFC3339, t)
}
return r
}
func convertProtoTime(t *timestamppb.Timestamp) time.Time {
var r time.Time
if t != nil {
r = t.AsTime()
}
return r
}
func toProtoTimestamp(t time.Time) *timestamppb.Timestamp {
if t.IsZero() {
return nil
}
return timestamppb.New(t)
}
func newObject(o *raw.Object) *ObjectAttrs {
if o == nil {
return nil
}
owner := ""
if o.Owner != nil {
owner = o.Owner.Entity
}
md5, _ := base64.StdEncoding.DecodeString(o.Md5Hash)
crc32c, _ := decodeUint32(o.Crc32c)
var sha256 string
if o.CustomerEncryption != nil {
sha256 = o.CustomerEncryption.KeySha256
}
return &ObjectAttrs{
Bucket: o.Bucket,
Name: o.Name,
ContentType: o.ContentType,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
EventBasedHold: o.EventBasedHold,
TemporaryHold: o.TemporaryHold,
RetentionExpirationTime: convertTime(o.RetentionExpirationTime),
ACL: toObjectACLRules(o.Acl),
Owner: owner,
ContentEncoding: o.ContentEncoding,
ContentDisposition: o.ContentDisposition,
Size: int64(o.Size),
MD5: md5,
CRC32C: crc32c,
MediaLink: o.MediaLink,
Metadata: o.Metadata,
Generation: o.Generation,
Metageneration: o.Metageneration,
StorageClass: o.StorageClass,
CustomerKeySHA256: sha256,
KMSKeyName: o.KmsKeyName,
Created: convertTime(o.TimeCreated),
Deleted: convertTime(o.TimeDeleted),
Updated: convertTime(o.Updated),
Etag: o.Etag,
CustomTime: convertTime(o.CustomTime),
ComponentCount: o.ComponentCount,
}
}
func newObjectFromProto(o *storagepb.Object) *ObjectAttrs {
if o == nil {
return nil
}
return &ObjectAttrs{
Bucket: parseBucketName(o.Bucket),
Name: o.Name,
ContentType: o.ContentType,
ContentLanguage: o.ContentLanguage,
CacheControl: o.CacheControl,
EventBasedHold: o.GetEventBasedHold(),
TemporaryHold: o.TemporaryHold,
RetentionExpirationTime: convertProtoTime(o.GetRetentionExpireTime()),
ACL: toObjectACLRulesFromProto(o.GetAcl()),
Owner: o.GetOwner().GetEntity(),
ContentEncoding: o.ContentEncoding,
ContentDisposition: o.ContentDisposition,
Size: int64(o.Size),
MD5: o.GetChecksums().GetMd5Hash(),
CRC32C: o.GetChecksums().GetCrc32C(),
Metadata: o.Metadata,
Generation: o.Generation,
Metageneration: o.Metageneration,
StorageClass: o.StorageClass,
// CustomerKeySHA256 needs to be presented as base64 encoded, but the response from gRPC is not.
CustomerKeySHA256: base64.StdEncoding.EncodeToString(o.GetCustomerEncryption().GetKeySha256Bytes()),
KMSKeyName: o.GetKmsKey(),
Created: convertProtoTime(o.GetCreateTime()),
Deleted: convertProtoTime(o.GetDeleteTime()),
Updated: convertProtoTime(o.GetUpdateTime()),
CustomTime: convertProtoTime(o.GetCustomTime()),
ComponentCount: int64(o.ComponentCount),
}
}
// Decode a uint32 encoded in Base64 in big-endian byte order.
func decodeUint32(b64 string) (uint32, error) {
d, err := base64.StdEncoding.DecodeString(b64)
if err != nil {
return 0, err
}
if len(d) != 4 {
return 0, fmt.Errorf("storage: %q does not encode a 32-bit value", d)
}
return uint32(d[0])<<24 + uint32(d[1])<<16 + uint32(d[2])<<8 + uint32(d[3]), nil
}
// Encode a uint32 as Base64 in big-endian byte order.
func encodeUint32(u uint32) string {
b := []byte{byte(u >> 24), byte(u >> 16), byte(u >> 8), byte(u)}
return base64.StdEncoding.EncodeToString(b)
}
// Projection is enumerated type for Query.Projection.
type Projection int
const (
// ProjectionDefault returns all fields of objects.
ProjectionDefault Projection = iota
// ProjectionFull returns all fields of objects.
ProjectionFull
// ProjectionNoACL returns all fields of objects except for Owner and ACL.
ProjectionNoACL
)
func (p Projection) String() string {
switch p {
case ProjectionFull:
return "full"
case ProjectionNoACL:
return "noAcl"
default:
return ""
}
}
// Query represents a query to filter objects from a bucket.
type Query struct {
// Delimiter returns results in a directory-like fashion.
// Results will contain only objects whose names, aside from the
// prefix, do not contain delimiter. Objects whose names,
// aside from the prefix, contain delimiter will have their name,
// truncated after the delimiter, returned in prefixes.
// Duplicate prefixes are omitted.
// Must be set to / when used with the MatchGlob parameter to filter results
// in a directory-like mode.
// Optional.
Delimiter string
// Prefix is the prefix filter to query objects
// whose names begin with this prefix.
// Optional.
Prefix string
// Versions indicates whether multiple versions of the same
// object will be included in the results.
Versions bool
// attrSelection is used to select only specific fields to be returned by
// the query. It is set by the user calling SetAttrSelection. These
// are used by toFieldMask and toFieldSelection for gRPC and HTTP/JSON
// clients respectively.
attrSelection []string
// StartOffset is used to filter results to objects whose names are
// lexicographically equal to or after startOffset. If endOffset is also set,
// the objects listed will have names between startOffset (inclusive) and
// endOffset (exclusive).
StartOffset string
// EndOffset is used to filter results to objects whose names are
// lexicographically before endOffset. If startOffset is also set, the objects
// listed will have names between startOffset (inclusive) and endOffset (exclusive).
EndOffset string
// Projection defines the set of properties to return. It will default to ProjectionFull,
// which returns all properties. Passing ProjectionNoACL will omit Owner and ACL,
// which may improve performance when listing many objects.
Projection Projection
// IncludeTrailingDelimiter controls how objects which end in a single
// instance of Delimiter (for example, if Query.Delimiter = "/" and the
// object name is "foo/bar/") are included in the results. By default, these
// objects only show up as prefixes. If IncludeTrailingDelimiter is set to
// true, they will also be included as objects and their metadata will be
// populated in the returned ObjectAttrs.
IncludeTrailingDelimiter bool
// MatchGlob is a glob pattern used to filter results (for example, foo*bar). See
// https://cloud.google.com/storage/docs/json_api/v1/objects/list#list-object-glob
// for syntax details. When Delimiter is set in conjunction with MatchGlob,
// it must be set to /.
MatchGlob string
}
// attrToFieldMap maps the field names of ObjectAttrs to the underlying field
// names in the API call. Only the ObjectAttrs field names are visible to users
// because they are already part of the public API of the package.
var attrToFieldMap = map[string]string{
"Bucket": "bucket",
"Name": "name",
"ContentType": "contentType",
"ContentLanguage": "contentLanguage",
"CacheControl": "cacheControl",
"EventBasedHold": "eventBasedHold",
"TemporaryHold": "temporaryHold",
"RetentionExpirationTime": "retentionExpirationTime",
"ACL": "acl",
"Owner": "owner",
"ContentEncoding": "contentEncoding",
"ContentDisposition": "contentDisposition",
"Size": "size",
"MD5": "md5Hash",
"CRC32C": "crc32c",
"MediaLink": "mediaLink",
"Metadata": "metadata",
"Generation": "generation",
"Metageneration": "metageneration",
"StorageClass": "storageClass",
"CustomerKeySHA256": "customerEncryption",
"KMSKeyName": "kmsKeyName",
"Created": "timeCreated",
"Deleted": "timeDeleted",
"Updated": "updated",
"Etag": "etag",
"CustomTime": "customTime",
"ComponentCount": "componentCount",
}
// attrToProtoFieldMap maps the field names of ObjectAttrs to the underlying field
// names in the protobuf Object message.
var attrToProtoFieldMap = map[string]string{
"Name": "name",
"Bucket": "bucket",
"Etag": "etag",
"Generation": "generation",
"Metageneration": "metageneration",
"StorageClass": "storage_class",
"Size": "size",
"ContentEncoding": "content_encoding",
"ContentDisposition": "content_disposition",
"CacheControl": "cache_control",
"ACL": "acl",
"ContentLanguage": "content_language",
"Deleted": "delete_time",
"ContentType": "content_type",
"Created": "create_time",
"CRC32C": "checksums.crc32c",
"MD5": "checksums.md5_hash",
"Updated": "update_time",
"KMSKeyName": "kms_key",
"TemporaryHold": "temporary_hold",
"RetentionExpirationTime": "retention_expire_time",
"Metadata": "metadata",
"EventBasedHold": "event_based_hold",
"Owner": "owner",
"CustomerKeySHA256": "customer_encryption",
"CustomTime": "custom_time",
"ComponentCount": "component_count",
// MediaLink was explicitly excluded from the proto as it is an HTTP-ism.
// "MediaLink": "mediaLink",
}
// SetAttrSelection makes the query populate only specific attributes of
// objects. When iterating over objects, if you only need each object's name
// and size, pass []string{"Name", "Size"} to this method. Only these fields
// will be fetched for each object across the network; the other fields of
// ObjectAttr will remain at their default values. This is a performance
// optimization; for more information, see
// https://cloud.google.com/storage/docs/json_api/v1/how-tos/performance
func (q *Query) SetAttrSelection(attrs []string) error {
// Validate selections.
for _, attr := range attrs {
// If the attr is acceptable for one of the two sets, then it is OK.
// If it is not acceptable for either, then return an error.
// The respective masking implementations ignore unknown attrs which
// makes switching between transports a little easier.
_, okJSON := attrToFieldMap[attr]
_, okGRPC := attrToProtoFieldMap[attr]
if !okJSON && !okGRPC {
return fmt.Errorf("storage: attr %v is not valid", attr)
}
}
q.attrSelection = attrs
return nil
}
func (q *Query) toFieldSelection() string {
if q == nil || len(q.attrSelection) == 0 {
return ""
}
fieldSet := make(map[string]bool)
for _, attr := range q.attrSelection {
field, ok := attrToFieldMap[attr]
if !ok {
// Future proofing, skip unknown fields, let SetAttrSelection handle
// error modes.
continue
}
fieldSet[field] = true
}
var s string
if len(fieldSet) > 0 {
var b bytes.Buffer
b.WriteString("prefixes,items(")
first := true
for field := range fieldSet {
if !first {
b.WriteString(",")
}
first = false
b.WriteString(field)
}
b.WriteString(")")
s = b.String()
}
return s
}
func (q *Query) toFieldMask() *fieldmaskpb.FieldMask {
// The default behavior with no Query is ProjectionDefault (i.e. ProjectionFull).
if q == nil {
return &fieldmaskpb.FieldMask{Paths: []string{"*"}}
}
// User selected attributes via q.SetAttrSeleciton. This takes precedence
// over the Projection.
if numSelected := len(q.attrSelection); numSelected > 0 {
protoFieldPaths := make([]string, 0, numSelected)
for _, attr := range q.attrSelection {
pf, ok := attrToProtoFieldMap[attr]
if !ok {
// Future proofing, skip unknown fields, let SetAttrSelection
// handle error modes.
continue
}
protoFieldPaths = append(protoFieldPaths, pf)
}
return &fieldmaskpb.FieldMask{Paths: protoFieldPaths}
}
// ProjectDefault == ProjectionFull which means all fields.
fm := &fieldmaskpb.FieldMask{Paths: []string{"*"}}
if q.Projection == ProjectionNoACL {
paths := make([]string, 0, len(attrToProtoFieldMap)-2) // omitting two fields
for _, f := range attrToProtoFieldMap {
// Skip the acl and owner fields for "NoACL".
if f == "acl" || f == "owner" {
continue
}
paths = append(paths, f)
}
fm.Paths = paths
}
return fm
}
// Conditions constrain methods to act on specific generations of
// objects.
//
// The zero value is an empty set of constraints. Not all conditions or
// combinations of conditions are applicable to all methods.
// See https://cloud.google.com/storage/docs/generations-preconditions
// for details on how these operate.
type Conditions struct {
// Generation constraints.
// At most one of the following can be set to a non-zero value.
// GenerationMatch specifies that the object must have the given generation
// for the operation to occur.
// If GenerationMatch is zero, it has no effect.
// Use DoesNotExist to specify that the object does not exist in the bucket.
GenerationMatch int64
// GenerationNotMatch specifies that the object must not have the given
// generation for the operation to occur.
// If GenerationNotMatch is zero, it has no effect.
// This condition only works for object reads if the WithJSONReads client
// option is set.
GenerationNotMatch int64
// DoesNotExist specifies that the object must not exist in the bucket for
// the operation to occur.
// If DoesNotExist is false, it has no effect.
DoesNotExist bool
// Metadata generation constraints.
// At most one of the following can be set to a non-zero value.
// MetagenerationMatch specifies that the object must have the given
// metageneration for the operation to occur.
// If MetagenerationMatch is zero, it has no effect.
MetagenerationMatch int64
// MetagenerationNotMatch specifies that the object must not have the given
// metageneration for the operation to occur.
// If MetagenerationNotMatch is zero, it has no effect.
// This condition only works for object reads if the WithJSONReads client
// option is set.
MetagenerationNotMatch int64
}
func (c *Conditions) validate(method string) error {
if *c == (Conditions{}) {
return fmt.Errorf("storage: %s: empty conditions", method)
}
if !c.isGenerationValid() {
return fmt.Errorf("storage: %s: multiple conditions specified for generation", method)
}
if !c.isMetagenerationValid() {
return fmt.Errorf("storage: %s: multiple conditions specified for metageneration", method)
}
return nil
}
func (c *Conditions) isGenerationValid() bool {
n := 0
if c.GenerationMatch != 0 {
n++
}
if c.GenerationNotMatch != 0 {
n++
}
if c.DoesNotExist {
n++
}
return n <= 1
}
func (c *Conditions) isMetagenerationValid() bool {
return c.MetagenerationMatch == 0 || c.MetagenerationNotMatch == 0
}
// applyConds modifies the provided call using the conditions in conds.
// call is something that quacks like a *raw.WhateverCall.
func applyConds(method string, gen int64, conds *Conditions, call interface{}) error {
cval := reflect.ValueOf(call)
if gen >= 0 {
if !setConditionField(cval, "Generation", gen) {
return fmt.Errorf("storage: %s: generation not supported", method)
}
}
if conds == nil {
return nil
}
if err := conds.validate(method); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
if !setConditionField(cval, "IfGenerationMatch", conds.GenerationMatch) {
return fmt.Errorf("storage: %s: ifGenerationMatch not supported", method)
}
case conds.GenerationNotMatch != 0:
if !setConditionField(cval, "IfGenerationNotMatch", conds.GenerationNotMatch) {
return fmt.Errorf("storage: %s: ifGenerationNotMatch not supported", method)
}
case conds.DoesNotExist:
if !setConditionField(cval, "IfGenerationMatch", int64(0)) {
return fmt.Errorf("storage: %s: DoesNotExist not supported", method)
}
}
switch {
case conds.MetagenerationMatch != 0:
if !setConditionField(cval, "IfMetagenerationMatch", conds.MetagenerationMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationMatch not supported", method)
}
case conds.MetagenerationNotMatch != 0:
if !setConditionField(cval, "IfMetagenerationNotMatch", conds.MetagenerationNotMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationNotMatch not supported", method)
}
}
return nil
}
func applySourceConds(gen int64, conds *Conditions, call *raw.ObjectsRewriteCall) error {
if gen >= 0 {
call.SourceGeneration(gen)
}
if conds == nil {
return nil
}
if err := conds.validate("CopyTo source"); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
call.IfSourceGenerationMatch(conds.GenerationMatch)
case conds.GenerationNotMatch != 0:
call.IfSourceGenerationNotMatch(conds.GenerationNotMatch)
case conds.DoesNotExist:
call.IfSourceGenerationMatch(0)
}
switch {
case conds.MetagenerationMatch != 0:
call.IfSourceMetagenerationMatch(conds.MetagenerationMatch)
case conds.MetagenerationNotMatch != 0:
call.IfSourceMetagenerationNotMatch(conds.MetagenerationNotMatch)
}
return nil
}
func applySourceCondsProto(gen int64, conds *Conditions, call *storagepb.RewriteObjectRequest) error {
if gen >= 0 {
call.SourceGeneration = gen
}
if conds == nil {
return nil
}
if err := conds.validate("CopyTo source"); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
call.IfSourceGenerationMatch = proto.Int64(conds.GenerationMatch)
case conds.GenerationNotMatch != 0:
call.IfSourceGenerationNotMatch = proto.Int64(conds.GenerationNotMatch)
case conds.DoesNotExist:
call.IfSourceGenerationMatch = proto.Int64(0)
}
switch {
case conds.MetagenerationMatch != 0:
call.IfSourceMetagenerationMatch = proto.Int64(conds.MetagenerationMatch)
case conds.MetagenerationNotMatch != 0:
call.IfSourceMetagenerationNotMatch = proto.Int64(conds.MetagenerationNotMatch)
}
return nil
}
// setConditionField sets a field on a *raw.WhateverCall.
// We can't use anonymous interfaces because the return type is
// different, since the field setters are builders.
func setConditionField(call reflect.Value, name string, value interface{}) bool {
m := call.MethodByName(name)
if !m.IsValid() {
return false
}
m.Call([]reflect.Value{reflect.ValueOf(value)})
return true
}
// Retryer returns an object handle that is configured with custom retry
// behavior as specified by the options that are passed to it. All operations
// on the new handle will use the customized retry configuration.
// These retry options will merge with the bucket's retryer (if set) for the
// returned handle. Options passed into this method will take precedence over
// retry options on the bucket and client. Note that you must explicitly pass in
// each option you want to override.
func (o *ObjectHandle) Retryer(opts ...RetryOption) *ObjectHandle {
o2 := *o
var retry *retryConfig
if o.retry != nil {
// merge the options with the existing retry
retry = o.retry
} else {
retry = &retryConfig{}
}
for _, opt := range opts {
opt.apply(retry)
}
o2.retry = retry
o2.acl.retry = retry
return &o2
}
// SetRetry configures the client with custom retry behavior as specified by the
// options that are passed to it. All operations using this client will use the
// customized retry configuration.
// This should be called once before using the client for network operations, as
// there could be indeterminate behaviour with operations in progress.
// Retry options set on a bucket or object handle will take precedence over
// these options.
func (c *Client) SetRetry(opts ...RetryOption) {
var retry *retryConfig
if c.retry != nil {
// merge the options with the existing retry
retry = c.retry
} else {
retry = &retryConfig{}
}
for _, opt := range opts {
opt.apply(retry)
}
c.retry = retry
}
// RetryOption allows users to configure non-default retry behavior for API
// calls made to GCS.
type RetryOption interface {
apply(config *retryConfig)
}
// WithBackoff allows configuration of the backoff timing used for retries.
// Available configuration options (Initial, Max and Multiplier) are described
// at https://pkg.go.dev/github.com/googleapis/gax-go/v2#Backoff. If any fields
// are not supplied by the user, gax default values will be used.
func WithBackoff(backoff gax.Backoff) RetryOption {
return &withBackoff{
backoff: backoff,
}
}
type withBackoff struct {
backoff gax.Backoff
}
func (wb *withBackoff) apply(config *retryConfig) {
config.backoff = &wb.backoff
}
// RetryPolicy describes the available policies for which operations should be
// retried. The default is `RetryIdempotent`.
type RetryPolicy int
const (
// RetryIdempotent causes only idempotent operations to be retried when the
// service returns a transient error. Using this policy, fully idempotent
// operations (such as `ObjectHandle.Attrs()`) will always be retried.
// Conditionally idempotent operations (for example `ObjectHandle.Update()`)
// will be retried only if the necessary conditions have been supplied (in
// the case of `ObjectHandle.Update()` this would mean supplying a
// `Conditions.MetagenerationMatch` condition is required).
RetryIdempotent RetryPolicy = iota
// RetryAlways causes all operations to be retried when the service returns a
// transient error, regardless of idempotency considerations.
RetryAlways
// RetryNever causes the client to not perform retries on failed operations.
RetryNever
)
// WithPolicy allows the configuration of which operations should be performed
// with retries for transient errors.
func WithPolicy(policy RetryPolicy) RetryOption {
return &withPolicy{
policy: policy,
}
}
type withPolicy struct {
policy RetryPolicy
}
func (ws *withPolicy) apply(config *retryConfig) {
config.policy = ws.policy
}
// WithErrorFunc allows users to pass a custom function to the retryer. Errors
// will be retried if and only if `shouldRetry(err)` returns true.
// By default, the following errors are retried (see ShouldRetry for the default
// function):
//
// - HTTP responses with codes 408, 429, 502, 503, and 504.
//
// - Transient network errors such as connection reset and io.ErrUnexpectedEOF.
//
// - Errors which are considered transient using the Temporary() interface.
//
// - Wrapped versions of these errors.
//
// This option can be used to retry on a different set of errors than the
// default. Users can use the default ShouldRetry function inside their custom
// function if they only want to make minor modifications to default behavior.
func WithErrorFunc(shouldRetry func(err error) bool) RetryOption {
return &withErrorFunc{
shouldRetry: shouldRetry,
}
}
type withErrorFunc struct {
shouldRetry func(err error) bool
}
func (wef *withErrorFunc) apply(config *retryConfig) {
config.shouldRetry = wef.shouldRetry
}
type retryConfig struct {
backoff *gax.Backoff
policy RetryPolicy
shouldRetry func(err error) bool
}
func (r *retryConfig) clone() *retryConfig {
if r == nil {
return nil
}
var bo *gax.Backoff
if r.backoff != nil {
bo = &gax.Backoff{
Initial: r.backoff.Initial,
Max: r.backoff.Max,
Multiplier: r.backoff.Multiplier,
}
}
return &retryConfig{
backoff: bo,
policy: r.policy,
shouldRetry: r.shouldRetry,
}
}
// composeSourceObj wraps a *raw.ComposeRequestSourceObjects, but adds the methods
// that modifyCall searches for by name.
type composeSourceObj struct {
src *raw.ComposeRequestSourceObjects
}
func (c composeSourceObj) Generation(gen int64) {
c.src.Generation = gen
}
func (c composeSourceObj) IfGenerationMatch(gen int64) {
// It's safe to overwrite ObjectPreconditions, since its only field is
// IfGenerationMatch.
c.src.ObjectPreconditions = &raw.ComposeRequestSourceObjectsObjectPreconditions{
IfGenerationMatch: gen,
}
}
func setEncryptionHeaders(headers http.Header, key []byte, copySource bool) error {
if key == nil {
return nil
}
// TODO(jbd): Ask the API team to return a more user-friendly error
// and avoid doing this check at the client level.
if len(key) != 32 {
return errors.New("storage: not a 32-byte AES-256 key")
}
var cs string
if copySource {
cs = "copy-source-"
}
headers.Set("x-goog-"+cs+"encryption-algorithm", aes256Algorithm)
headers.Set("x-goog-"+cs+"encryption-key", base64.StdEncoding.EncodeToString(key))
keyHash := sha256.Sum256(key)
headers.Set("x-goog-"+cs+"encryption-key-sha256", base64.StdEncoding.EncodeToString(keyHash[:]))
return nil
}
// toProtoCommonObjectRequestParams sets customer-supplied encryption to the proto library's CommonObjectRequestParams.
func toProtoCommonObjectRequestParams(key []byte) *storagepb.CommonObjectRequestParams {
if key == nil {
return nil
}
keyHash := sha256.Sum256(key)
return &storagepb.CommonObjectRequestParams{
EncryptionAlgorithm: aes256Algorithm,
EncryptionKeyBytes: key,
EncryptionKeySha256Bytes: keyHash[:],
}
}
func toProtoChecksums(sendCRC32C bool, attrs *ObjectAttrs) *storagepb.ObjectChecksums {
var checksums *storagepb.ObjectChecksums
if sendCRC32C {
checksums = &storagepb.ObjectChecksums{
Crc32C: proto.Uint32(attrs.CRC32C),
}
}
if len(attrs.MD5) != 0 {
if checksums == nil {
checksums = &storagepb.ObjectChecksums{
Md5Hash: attrs.MD5,
}
} else {
checksums.Md5Hash = attrs.MD5
}
}
return checksums
}
// ServiceAccount fetches the email address of the given project's Google Cloud Storage service account.
func (c *Client) ServiceAccount(ctx context.Context, projectID string) (string, error) {
o := makeStorageOpts(true, c.retry, "")
return c.tc.GetServiceAccount(ctx, projectID, o...)
}
// bucketResourceName formats the given project ID and bucketResourceName ID
// into a Bucket resource name. This is the format necessary for the gRPC API as
// it conforms to the Resource-oriented design practices in https://google.aip.dev/121.
func bucketResourceName(p, b string) string {
return fmt.Sprintf("projects/%s/buckets/%s", p, b)
}
// parseBucketName strips the leading resource path segment and returns the
// bucket ID, which is the simple Bucket name typical of the v1 API.
func parseBucketName(b string) string {
sep := strings.LastIndex(b, "/")
return b[sep+1:]
}
// parseProjectNumber consume the given resource name and parses out the project
// number if one is present i.e. it is not a project ID.
func parseProjectNumber(r string) uint64 {
projectID := regexp.MustCompile(`projects\/([0-9]+)\/?`)
if matches := projectID.FindStringSubmatch(r); len(matches) > 0 {
// Capture group follows the matched segment. For example:
// input: projects/123/bars/456
// output: [projects/123/, 123]
number, err := strconv.ParseUint(matches[1], 10, 64)
if err != nil {
return 0
}
return number
}
return 0
}
// toProjectResource accepts a project ID and formats it as a Project resource
// name.
func toProjectResource(project string) string {
return fmt.Sprintf("projects/%s", project)
}
// setConditionProtoField uses protobuf reflection to set named condition field
// to the given condition value if supported on the protobuf message.
//
// This is an experimental API and not intended for public use.
func setConditionProtoField(m protoreflect.Message, f string, v int64) bool {
fields := m.Descriptor().Fields()
if rf := fields.ByName(protoreflect.Name(f)); rf != nil {
m.Set(rf, protoreflect.ValueOfInt64(v))
return true
}
return false
}
// applyCondsProto validates and attempts to set the conditions on a protobuf
// message using protobuf reflection.
//
// This is an experimental API and not intended for public use.
func applyCondsProto(method string, gen int64, conds *Conditions, msg proto.Message) error {
rmsg := msg.ProtoReflect()
if gen >= 0 {
if !setConditionProtoField(rmsg, "generation", gen) {
return fmt.Errorf("storage: %s: generation not supported", method)
}
}
if conds == nil {
return nil
}
if err := conds.validate(method); err != nil {
return err
}
switch {
case conds.GenerationMatch != 0:
if !setConditionProtoField(rmsg, "if_generation_match", conds.GenerationMatch) {
return fmt.Errorf("storage: %s: ifGenerationMatch not supported", method)
}
case conds.GenerationNotMatch != 0:
if !setConditionProtoField(rmsg, "if_generation_not_match", conds.GenerationNotMatch) {
return fmt.Errorf("storage: %s: ifGenerationNotMatch not supported", method)
}
case conds.DoesNotExist:
if !setConditionProtoField(rmsg, "if_generation_match", int64(0)) {
return fmt.Errorf("storage: %s: DoesNotExist not supported", method)
}
}
switch {
case conds.MetagenerationMatch != 0:
if !setConditionProtoField(rmsg, "if_metageneration_match", conds.MetagenerationMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationMatch not supported", method)
}
case conds.MetagenerationNotMatch != 0:
if !setConditionProtoField(rmsg, "if_metageneration_not_match", conds.MetagenerationNotMatch) {
return fmt.Errorf("storage: %s: ifMetagenerationNotMatch not supported", method)
}
}
return nil
}