pkg/gcs: add new package

Move GCS-related functionality from syz-gce
to a separate package.

1 files changed, 107 insertions, 0 deletions

diff --git a/pkg/gcs/gcs.go b/pkg/gcs/gcs.go
new file mode 100644
index 000000000..ac95ec420
--- /dev/null
+++ b/pkg/gcs/gcs.go
@@ -0,0 +1,107 @@
+// 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"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
+
+	"cloud.google.com/go/storage"
+)
+
+type Client struct {
+	client *storage.Client
+	ctx    context.Context
+}
+
+type File struct {
+	Updated time.Time
+
+	ctx    context.Context
+	handle *storage.ObjectHandle
+}
+
+func (file *File) Reader() (io.ReadCloser, error) {
+	return file.handle.NewReader(file.ctx)
+}
+
+func NewClient() (*Client, error) {
+	ctx := context.Background()
+	storageClient, err := storage.NewClient(ctx)
+	if err != nil {
+		return nil, err
+	}
+	client := &Client{
+		client: storageClient,
+		ctx:    ctx,
+	}
+	return client, nil
+}
+
+func (client *Client) Read(gcsFile string) (*File, error) {
+	bucket, filename, err := split(gcsFile)
+	if err != nil {
+		return nil, err
+	}
+	bkt := client.client.Bucket(bucket)
+	f := bkt.Object(filename)
+	attrs, err := f.Attrs(client.ctx)
+	if err != nil {
+		return nil, fmt.Errorf("failed to read %v attributes: %v", 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,
+	})
+	file := &File{
+		Updated: attrs.Updated,
+		ctx:     client.ctx,
+		handle:  handle,
+	}
+	return file, nil
+}
+
+func (client *Client) UploadFile(localFile, gcsFile string) error {
+	bucket, filename, err := split(gcsFile)
+	if err != nil {
+		return err
+	}
+	local, err := os.Open(localFile)
+	if err != nil {
+		return err
+	}
+	defer local.Close()
+	bkt := client.client.Bucket(bucket)
+	f := bkt.Object(filename)
+	w := f.NewWriter(client.ctx)
+	defer w.Close()
+	if _, err := io.Copy(w, local); err != nil {
+		return err
+	}
+	return nil
+}
+
+func split(file string) (bucket, filename string, err error) {
+	if strings.HasPrefix(file, "gs://") {
+		file = file[5:]
+	}
+	pos := strings.IndexByte(file, '/')
+	if pos == -1 {
+		return "", "", fmt.Errorf("invalid GCS file name: %v", file)
+	}
+	return file[:pos], file[pos+1:], nil
+}