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// Copyright 2017 syzkaller project authors. All rights reserved.
// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
// Package gcs provides wrappers around Google Cloud Storage (GCS) APIs.
// Package uses Application Default Credentials assuming that the program runs on GCE.
//
// See the following links for details and API reference:
// https://cloud.google.com/go/getting-started/using-cloud-storage
// https://godoc.org/cloud.google.com/go/storage
package gcs
import (
"context"
"errors"
"fmt"
"io"
"strings"
"time"
"cloud.google.com/go/storage"
"google.golang.org/api/iterator"
)
type Client interface {
Close() error
FileReader(path string) (io.ReadCloser, error)
FileWriter(path string, contentType string, contentEncoding string) (io.WriteCloser, error)
DeleteFile(path string) error
FileExists(path string) (bool, error)
ListObjects(path string) ([]*Object, error)
Publish(path string) error
}
type UploadOptions struct {
Publish bool
ContentEncoding string
GCSClientMock Client
}
func UploadFile(ctx context.Context, srcFile io.Reader, destURL string, opts UploadOptions) error {
destURL = strings.TrimPrefix(destURL, "gs://")
var err error
gcsClient := opts.GCSClientMock
if gcsClient == nil {
if gcsClient, err = NewClient(ctx); err != nil {
return fmt.Errorf("func NewClient: %w", err)
}
}
defer gcsClient.Close()
gcsWriter, err := gcsClient.FileWriter(destURL, "", opts.ContentEncoding)
if err != nil {
return fmt.Errorf("client.FileWriter: %w", err)
}
if _, err := io.Copy(gcsWriter, srcFile); err != nil {
gcsWriter.Close()
return fmt.Errorf("io.Copy: %w", err)
}
if err := gcsWriter.Close(); err != nil {
return fmt.Errorf("gcsWriter.Close: %w", err)
}
if opts.Publish {
return gcsClient.Publish(destURL)
}
return nil
}
type client struct {
client *storage.Client
ctx context.Context
}
func NewClient(ctx context.Context) (Client, error) {
storageClient, err := storage.NewClient(ctx)
if err != nil {
return nil, err
}
c := &client{
client: storageClient,
ctx: ctx,
}
return c, nil
}
func (c *client) Close() error {
return c.client.Close()
}
func (c *client) FileReader(gcsFile string) (io.ReadCloser, error) {
bucket, filename, err := split(gcsFile)
if err != nil {
return nil, err
}
bkt := c.client.Bucket(bucket)
f := bkt.Object(filename)
attrs, err := f.Attrs(c.ctx)
if err != nil {
return nil, fmt.Errorf("failed to read %v attributes: %w", gcsFile, err)
}
if !attrs.Deleted.IsZero() {
return nil, fmt.Errorf("file %v is deleted", gcsFile)
}
handle := f.If(storage.Conditions{
GenerationMatch: attrs.Generation,
MetagenerationMatch: attrs.Metageneration,
})
return handle.NewReader(c.ctx)
}
func (c *client) FileWriter(gcsFile, contentType, contentEncoding string) (io.WriteCloser, error) {
bucket, filename, err := split(gcsFile)
if err != nil {
return nil, err
}
bkt := c.client.Bucket(bucket)
f := bkt.Object(filename)
w := f.NewWriter(c.ctx)
if contentType != "" {
w.ContentType = contentType
}
if contentEncoding != "" {
w.ContentEncoding = contentEncoding
}
return w, nil
}
// Publish lets any user read gcsFile.
func (c *client) Publish(gcsFile string) error {
bucket, filename, err := split(gcsFile)
if err != nil {
return err
}
obj := c.client.Bucket(bucket).Object(filename)
return obj.ACL().Set(c.ctx, storage.AllUsers, storage.RoleReader)
}
var ErrFileNotFound = errors.New("the requested files does not exist")
func (c *client) DeleteFile(gcsFile string) error {
bucket, filename, err := split(gcsFile)
if err != nil {
return err
}
err = c.client.Bucket(bucket).Object(filename).Delete(c.ctx)
if errors.Is(err, storage.ErrObjectNotExist) {
return ErrFileNotFound
}
return err
}
func (c *client) FileExists(gcsFile string) (bool, error) {
bucket, filename, err := split(gcsFile)
if err != nil {
return false, err
}
_, err = c.client.Bucket(bucket).Object(filename).Attrs(c.ctx)
if errors.Is(err, storage.ErrObjectNotExist) {
return false, nil
} else if err != nil {
return false, err
}
return true, nil
}
// Where things get published.
const (
PublicPrefix = "https://storage.googleapis.com/"
AuthenticatedPrefix = "https://storage.cloud.google.com/"
)
func GetDownloadURL(gcsFile string, publicURL bool) string {
gcsFile = strings.TrimPrefix(gcsFile, "/")
if publicURL {
return PublicPrefix + gcsFile
}
return AuthenticatedPrefix + gcsFile
}
type Object struct {
Path string
CreatedAt time.Time
}
// ListObjects expects "bucket/path" or "bucket" as input.
func (c *client) ListObjects(bucketObjectPath string) ([]*Object, error) {
bucket, objectPath, err := split(bucketObjectPath)
if err != nil { // no path specified
bucket = bucketObjectPath
}
query := &storage.Query{Prefix: objectPath}
it := c.client.Bucket(bucket).Objects(c.ctx, query)
ret := []*Object{}
for {
objAttrs, err := it.Next()
if err == iterator.Done {
break
}
if err != nil {
return nil, fmt.Errorf("failed to query GCS objects: %w", err)
}
ret = append(ret, &Object{
Path: objAttrs.Name,
CreatedAt: objAttrs.Created,
})
}
return ret, nil
}
func split(file string) (bucket, filename string, err error) {
pos := strings.IndexByte(file, '/')
if pos == -1 {
return "", "", fmt.Errorf("invalid GCS file name: %v", file)
}
return file[:pos], file[pos+1:], nil
}
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