| // Copyright 2020 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| package main |
| |
| import ( |
| "context" |
| "fmt" |
| "io" |
| "strings" |
| |
| "cloud.google.com/go/storage" |
| ) |
| |
| // Abstract bucket storage interface. |
| type bucket interface { |
| objectExists(context.Context, string) (bool, error) |
| upload(context.Context, string, io.Reader) error |
| } |
| |
| // GCSBucket implements the Bucket interface using cloud storage. |
| type GCSBucket struct { |
| bkt *storage.BucketHandle |
| } |
| |
| func (bkt *GCSBucket) objectExists(ctx context.Context, object string) (bool, error) { |
| obj := bkt.bkt.Object(object) |
| _, err := obj.Attrs(ctx) |
| if err == storage.ErrObjectNotExist { |
| return false, nil |
| } else if err != nil { |
| return false, fmt.Errorf("object possibly exists, but is in unknown state: %v", err) |
| } |
| return true, nil |
| } |
| |
| func (bkt *GCSBucket) upload(ctx context.Context, object string, r io.Reader) error { |
| wc := bkt.bkt.Object(object).If(storage.Conditions{DoesNotExist: true}).NewWriter(ctx) |
| if _, err := io.Copy(wc, r); err != nil { |
| wc.Close() |
| return fmt.Errorf("failed to write object %q: %v", object, err) |
| } |
| // Close completes the write operation and flushes any buffered data. |
| if err := wc.Close(); err != nil { |
| // Error 412 means the precondition of DoesNotExist doesn't match. |
| // It is the expected behavior since we don't want to upload duplicated files. |
| if !strings.Contains(err.Error(), "Error 412") { |
| return fmt.Errorf("failed in close: %v", err) |
| } |
| } |
| return nil |
| } |
| |
| // newGCSBucket returns a new GCSBucket object for the given bucket name. |
| func newGCSBucket(ctx context.Context, name string) (*GCSBucket, error) { |
| client, err := storage.NewClient(ctx) |
| if err != nil { |
| return nil, fmt.Errorf("failed to create client: %v", err) |
| } |
| return &GCSBucket{bkt: client.Bucket(name)}, nil |
| } |