forked from kopia/kopia
/
gcs_storage.go
297 lines (236 loc) · 7.52 KB
/
gcs_storage.go
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// Package gcs implements Storage based on Google Cloud Storage bucket.
package gcs
import (
"context"
"encoding/json"
"fmt"
"net/http"
"os"
gcsclient "cloud.google.com/go/storage"
"github.com/pkg/errors"
"golang.org/x/oauth2"
"golang.org/x/oauth2/google"
"google.golang.org/api/googleapi"
"google.golang.org/api/iterator"
"google.golang.org/api/option"
"github.com/kopia/kopia/internal/clock"
"github.com/kopia/kopia/internal/iocopy"
"github.com/kopia/kopia/internal/timestampmeta"
"github.com/kopia/kopia/repo/blob"
"github.com/kopia/kopia/repo/blob/retrying"
)
const (
gcsStorageType = "gcs"
writerChunkSize = 1 << 20
timeMapKey = "Kopia-Mtime" // case is important, first letter must be capitalized.
)
type gcsStorage struct {
Options
storageClient *gcsclient.Client
bucket *gcsclient.BucketHandle
}
func (gcs *gcsStorage) GetBlob(ctx context.Context, b blob.ID, offset, length int64, output blob.OutputBuffer) error {
if offset < 0 {
return blob.ErrInvalidRange
}
attempt := func() error {
reader, err := gcs.bucket.Object(gcs.getObjectNameString(b)).NewRangeReader(ctx, offset, length)
if err != nil {
return errors.Wrap(err, "NewRangeReader")
}
defer reader.Close() //nolint:errcheck
// nolint:wrapcheck
return iocopy.JustCopy(output, reader)
}
if err := attempt(); err != nil {
return translateError(err)
}
// nolint:wrapcheck
return blob.EnsureLengthExactly(output.Length(), length)
}
func (gcs *gcsStorage) GetMetadata(ctx context.Context, b blob.ID) (blob.Metadata, error) {
attrs, err := gcs.bucket.Object(gcs.getObjectNameString(b)).Attrs(ctx)
if err != nil {
return blob.Metadata{}, errors.Wrap(translateError(err), "Attrs")
}
bm := blob.Metadata{
BlobID: b,
Length: attrs.Size,
Timestamp: attrs.Created,
}
if t, ok := timestampmeta.FromValue(attrs.Metadata[timeMapKey]); ok {
bm.Timestamp = t
}
return bm, nil
}
func translateError(err error) error {
var ae *googleapi.Error
if errors.As(err, &ae) {
switch ae.Code {
case http.StatusRequestedRangeNotSatisfiable:
return blob.ErrInvalidRange
case http.StatusPreconditionFailed:
return blob.ErrBlobAlreadyExists
}
}
switch {
case err == nil:
return nil
case errors.Is(err, gcsclient.ErrObjectNotExist):
return blob.ErrBlobNotFound
default:
return errors.Wrap(err, "unexpected GCS error")
}
}
func (gcs *gcsStorage) PutBlob(ctx context.Context, b blob.ID, data blob.Bytes, opts blob.PutOptions) error {
if opts.HasRetentionOptions() {
return errors.New("setting blob-retention is not supported")
}
ctx, cancel := context.WithCancel(ctx)
conds := gcsclient.Conditions{DoesNotExist: opts.DoNotRecreate}
obj := gcs.bucket.Object(gcs.getObjectNameString(b)).If(conds)
writer := obj.NewWriter(ctx)
writer.ChunkSize = writerChunkSize
writer.ContentType = "application/x-kopia"
writer.ObjectAttrs.Metadata = timestampmeta.ToMap(opts.SetModTime, timeMapKey)
err := iocopy.JustCopy(writer, data.Reader())
if err != nil {
// cancel context before closing the writer causes it to abandon the upload.
cancel()
_ = writer.Close() // failing already, ignore the error
return translateError(err)
}
defer cancel()
// calling close before cancel() causes it to commit the upload.
if err := writer.Close(); err != nil {
return translateError(err)
}
if opts.GetModTime != nil {
*opts.GetModTime = writer.Attrs().Updated
}
return nil
}
func (gcs *gcsStorage) DeleteBlob(ctx context.Context, b blob.ID) error {
err := translateError(gcs.bucket.Object(gcs.getObjectNameString(b)).Delete(ctx))
if errors.Is(err, blob.ErrBlobNotFound) {
return nil
}
return err
}
func (gcs *gcsStorage) getObjectNameString(blobID blob.ID) string {
return gcs.Prefix + string(blobID)
}
func (gcs *gcsStorage) ListBlobs(ctx context.Context, prefix blob.ID, callback func(blob.Metadata) error) error {
lst := gcs.bucket.Objects(ctx, &gcsclient.Query{
Prefix: gcs.getObjectNameString(prefix),
})
oa, err := lst.Next()
for err == nil {
bm := blob.Metadata{
BlobID: blob.ID(oa.Name[len(gcs.Prefix):]),
Length: oa.Size,
Timestamp: oa.Created,
}
if t, ok := timestampmeta.FromValue(oa.Metadata[timeMapKey]); ok {
bm.Timestamp = t
}
if cberr := callback(bm); cberr != nil {
return cberr
}
oa, err = lst.Next()
}
if !errors.Is(err, iterator.Done) {
return errors.Wrap(err, "ListBlobs")
}
return nil
}
func (gcs *gcsStorage) ConnectionInfo() blob.ConnectionInfo {
return blob.ConnectionInfo{
Type: gcsStorageType,
Config: &gcs.Options,
}
}
func (gcs *gcsStorage) DisplayName() string {
return fmt.Sprintf("GCS: %v", gcs.BucketName)
}
func (gcs *gcsStorage) Close(ctx context.Context) error {
return errors.Wrap(gcs.storageClient.Close(), "error closing GCS storage")
}
func (gcs *gcsStorage) FlushCaches(ctx context.Context) error {
return nil
}
func tokenSourceFromCredentialsFile(ctx context.Context, fn string, scopes ...string) (oauth2.TokenSource, error) {
data, err := os.ReadFile(fn) //nolint:gosec
if err != nil {
return nil, errors.Wrap(err, "error reading credentials file")
}
cfg, err := google.JWTConfigFromJSON(data, scopes...)
if err != nil {
return nil, errors.Wrap(err, "google.JWTConfigFromJSON")
}
return cfg.TokenSource(ctx), nil
}
func tokenSourceFromCredentialsJSON(ctx context.Context, data json.RawMessage, scopes ...string) (oauth2.TokenSource, error) {
cfg, err := google.JWTConfigFromJSON([]byte(data), scopes...)
if err != nil {
return nil, errors.Wrap(err, "google.JWTConfigFromJSON")
}
return cfg.TokenSource(ctx), nil
}
// New creates new Google Cloud Storage-backed storage with specified options:
//
// - the 'BucketName' field is required and all other parameters are optional.
//
// By default the connection reuses credentials managed by (https://cloud.google.com/sdk/),
// but this can be disabled by setting IgnoreDefaultCredentials to true.
func New(ctx context.Context, opt *Options) (blob.Storage, error) {
var ts oauth2.TokenSource
var err error
scope := gcsclient.ScopeReadWrite
if opt.ReadOnly {
scope = gcsclient.ScopeReadOnly
}
if sa := opt.ServiceAccountCredentialJSON; len(sa) > 0 {
ts, err = tokenSourceFromCredentialsJSON(ctx, sa, scope)
} else if sa := opt.ServiceAccountCredentialsFile; sa != "" {
ts, err = tokenSourceFromCredentialsFile(ctx, sa, scope)
} else {
ts, err = google.DefaultTokenSource(ctx, scope)
}
if err != nil {
return nil, errors.Wrap(err, "unable to initialize token source")
}
hc := oauth2.NewClient(ctx, ts)
cli, err := gcsclient.NewClient(ctx, option.WithHTTPClient(hc))
if err != nil {
return nil, errors.Wrap(err, "unable to create GCS client")
}
if opt.BucketName == "" {
return nil, errors.New("bucket name must be specified")
}
gcs := &gcsStorage{
Options: *opt,
storageClient: cli,
bucket: cli.Bucket(opt.BucketName),
}
// verify GCS connection is functional by listing blobs in a bucket, which will fail if the bucket
// does not exist. We list with a prefix that will not exist, to avoid iterating through any objects.
nonExistentPrefix := fmt.Sprintf("kopia-gcs-storage-initializing-%v", clock.Now().UnixNano())
err = gcs.ListBlobs(ctx, blob.ID(nonExistentPrefix), func(md blob.Metadata) error {
return nil
})
if err != nil {
return nil, errors.Wrap(err, "unable to list from the bucket")
}
return retrying.NewWrapper(gcs), nil
}
func init() {
blob.AddSupportedStorage(
gcsStorageType,
func() interface{} {
return &Options{}
},
func(ctx context.Context, o interface{}, isCreate bool) (blob.Storage, error) {
return New(ctx, o.(*Options))
})
}