// Copyright 2017 syzkaller project authors. All rights reserved.
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// Use of this source code is governed by Apache 2 LICENSE that can be found in the LICENSE file.
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// Package gcs provides wrappers around Google Cloud Storage (GCS) APIs.
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// Package uses Application Default Credentials assuming that the program runs on GCE.
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//
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// See the following links for details and API reference:
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// https://cloud.google.com/go/getting-started/using-cloud-storage
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// https://godoc.org/cloud.google.com/go/storage
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package gcs
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import (
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"context"
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"fmt"
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"io"
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"os"
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"strings"
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"time"
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"cloud.google.com/go/storage"
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)
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type Client struct {
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client *storage.Client
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ctx context.Context
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}
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type File struct {
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Updated time.Time
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ctx context.Context
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handle *storage.ObjectHandle
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}
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func (file *File) Reader() (io.ReadCloser, error) {
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return file.handle.NewReader(file.ctx)
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}
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func NewClient() (*Client, error) {
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ctx := context.Background()
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storageClient, err := storage.NewClient(ctx)
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if err != nil {
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return nil, err
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}
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client := &Client{
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client: storageClient,
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ctx: ctx,
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}
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return client, nil
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}
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func (client *Client) Close() {
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client.client.Close()
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}
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func (client *Client) Read(gcsFile string) (*File, error) {
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bucket, filename, err := split(gcsFile)
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if err != nil {
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return nil, err
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}
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bkt := client.client.Bucket(bucket)
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f := bkt.Object(filename)
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attrs, err := f.Attrs(client.ctx)
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if err != nil {
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return nil, fmt.Errorf("failed to read %v attributes: %v", gcsFile, err)
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}
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if !attrs.Deleted.IsZero() {
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return nil, fmt.Errorf("file %v is deleted", gcsFile)
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}
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handle := f.If(storage.Conditions{
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GenerationMatch: attrs.Generation,
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MetagenerationMatch: attrs.Metageneration,
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})
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file := &File{
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Updated: attrs.Updated,
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ctx: client.ctx,
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handle: handle,
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}
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return file, nil
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}
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func (client *Client) UploadFile(localFile, gcsFile string) error {
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local, err := os.Open(localFile)
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if err != nil {
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return err
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}
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defer local.Close()
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w, err := client.FileWriter(gcsFile)
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if err != nil {
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return err
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}
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defer w.Close()
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_, err = io.Copy(w, local)
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return err
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}
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func (client *Client) FileWriter(gcsFile string) (io.WriteCloser, error) {
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bucket, filename, err := split(gcsFile)
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if err != nil {
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return nil, err
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}
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bkt := client.client.Bucket(bucket)
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f := bkt.Object(filename)
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w := f.NewWriter(client.ctx)
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return w, nil
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}
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func split(file string) (bucket, filename string, err error) {
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pos := strings.IndexByte(file, '/')
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if pos == -1 {
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return "", "", fmt.Errorf("invalid GCS file name: %v", file)
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}
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return file[:pos], file[pos+1:], nil
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}
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