Google cloud storage v1 (#1)

* WIP

* The turd passes all tests

* Truncate performance improvement

gcs.go

@@ -0,0 +1,86 @@
+// Copyright © 2018 Mikael Rapp, github.com/zatte
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package afero
+
+import (
+	"log"
+	"os"
+	"time"
+
+	"cloud.google.com/go/storage"
+	"github.com/zatte/afero/gcs"
+
+	"golang.org/x/net/context"
+)
+
+func NewGcsFs(ctx context.Context, cl *storage.Client, bucket string, folderSep string) Fs {
+	return &GcsFsWrapper{
+		gcs.NewGcsFs(ctx, cl, bucket, folderSep),
+	}
+}
+
+// NewGcsFsFromDefaultCredentials Creates a GCS client assuming that
+// $GOOGLE_APPLICATION_CREDENTIALS is set and points to a service account
+func NewGcsFsFromDefaultCredentials(ctx context.Context, bucket string, folderSep string) Fs {
+	client, err := storage.NewClient(ctx)
+	if err != nil {
+		log.Fatalf("Failed to create client: %v", err)
+	}
+
+	return &GcsFsWrapper{
+		gcs.NewGcsFs(ctx, client, bucket, folderSep),
+	}
+}
+
+//Only wrapes gcs.GcsFs and convert some return types to afero interfaces.
+type GcsFsWrapper struct {
+	GcsFs *gcs.GcsFs
+}
+
+func (fs *GcsFsWrapper) Name() string {
+	return fs.GcsFs.Name()
+}
+func (fs *GcsFsWrapper) Create(name string) (File, error) {
+	return fs.GcsFs.Create(name)
+}
+func (fs *GcsFsWrapper) Mkdir(name string, perm os.FileMode) error {
+	return fs.GcsFs.Mkdir(name, perm)
+}
+func (fs *GcsFsWrapper) MkdirAll(path string, perm os.FileMode) error {
+	return fs.GcsFs.MkdirAll(path, perm)
+}
+func (fs *GcsFsWrapper) Open(name string) (File, error) {
+	return fs.GcsFs.Open(name)
+}
+func (fs *GcsFsWrapper) OpenFile(name string, flag int, perm os.FileMode) (File, error) {
+	return fs.GcsFs.OpenFile(name, flag, perm)
+}
+func (fs *GcsFsWrapper) Remove(name string) error {
+	return fs.GcsFs.Remove(name)
+}
+func (fs *GcsFsWrapper) RemoveAll(path string) error {
+	return fs.GcsFs.RemoveAll(path)
+}
+func (fs *GcsFsWrapper) Rename(oldname, newname string) error {
+	return fs.GcsFs.Rename(oldname, newname)
+}
+func (fs *GcsFsWrapper) Stat(name string) (os.FileInfo, error) {
+	return fs.GcsFs.Stat(name)
+}
+func (fs *GcsFsWrapper) Chmod(name string, mode os.FileMode) error {
+	return fs.GcsFs.Chmod(name, mode)
+}
+func (fs *GcsFsWrapper) Chtimes(name string, atime time.Time, mtime time.Time) error {
+	return fs.GcsFs.Chtimes(name, atime, mtime)
+}

gcs/errors.go

@@ -0,0 +1,13 @@
+package gcs
+
+import (
+	"errors"
+	"os"
+)
+
+var (
+	ErrFileClosed   = errors.New("File is closed")
+	ErrOutOfRange   = errors.New("Out of range")
+	ErrTooLarge     = errors.New("Too large")
+	ErrFileNotFound = os.ErrNotExist
+)

gcs/gcsFile.go

@@ -0,0 +1,250 @@
+// Copyright © 2018 Mikael Rapp, github.com/zatte
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package gcs
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+	"os"
+	"sort"
+
+	"cloud.google.com/go/storage"
+
+	"google.golang.org/api/iterator"
+)
+
+// GcsFs is the Afero version adapted for GCS
+type GcsFile struct {
+	openFlags int
+	fileMode  os.FileMode
+	fhoffset  int64 //File handle specific offset
+	closed    bool
+	ReadDirIt *storage.ObjectIterator
+	resource  *gcsFileResource
+}
+
+func NewGcsFile(
+	ctx context.Context,
+	fs *GcsFs,
+	obj *storage.ObjectHandle,
+	openFlags int,
+	fileMode os.FileMode,
+	name string,
+) *GcsFile {
+	return &GcsFile{
+		openFlags: openFlags,
+		fileMode:  fileMode,
+		fhoffset:  0,
+		closed:    false,
+		ReadDirIt: nil,
+		resource: &gcsFileResource{
+			ctx: ctx,
+			fs:  fs,
+
+			obj:  obj,
+			name: name,
+
+			currentGcsSize: 0,
+
+			offset: 0,
+			reader: nil,
+			writer: nil,
+		},
+	}
+}
+
+func NewGcsFileFromOldFH(
+	openFlags int,
+	fileMode os.FileMode,
+	oldFile *gcsFileResource,
+) *GcsFile {
+	return &GcsFile{
+		openFlags: openFlags,
+		fileMode:  fileMode,
+		fhoffset:  0,
+		closed:    false,
+		ReadDirIt: nil,
+
+		resource: oldFile,
+	}
+}
+
+func (o *GcsFile) Close() error {
+	// Threre shouldn't be a case where both are open at the same time
+	// but the check is omitted at this time.
+	o.closed = true
+	return o.resource.Close()
+}
+
+func (o *GcsFile) Seek(newOffset int64, whence int) (int64, error) {
+	if o.closed {
+		return 0, ErrFileClosed
+	}
+
+	//Since this is an expensive operation; let's make sure we need it
+	if (whence == 0 && newOffset == o.fhoffset) || (whence == 1 && newOffset == 0) {
+		return o.fhoffset, nil
+	}
+	log.Printf("WARNING; Seek beavhior triggerd, highly inefficent. Offset before seek is at %d\n", o.fhoffset)
+
+	//Fore the reader/writers to be reopened (at correct offset)
+	o.Sync()
+	stat, err := o.Stat()
+	if err != nil {
+		return 0, nil
+	}
+
+	switch whence {
+	case 0:
+		o.fhoffset = newOffset
+	case 1:
+		o.fhoffset += newOffset
+	case 2:
+		o.fhoffset = stat.Size() + newOffset
+	}
+	return o.fhoffset, nil
+}
+
+func (o *GcsFile) Read(p []byte) (n int, err error) {
+	return o.ReadAt(p, o.fhoffset)
+}
+
+func (o *GcsFile) ReadAt(p []byte, off int64) (n int, err error) {
+	if o.closed {
+		return 0, ErrFileClosed
+	}
+
+	read, err := o.resource.ReadAt(p, off)
+	o.fhoffset += int64(read)
+	return read, err
+}
+
+func (o *GcsFile) Write(p []byte) (n int, err error) {
+	return o.WriteAt(p, o.fhoffset)
+}
+
+func (o *GcsFile) WriteAt(b []byte, off int64) (n int, err error) {
+	if o.closed {
+		return 0, ErrFileClosed
+	}
+
+	if o.openFlags == os.O_RDONLY {
+		return 0, fmt.Errorf("File is opend as read only")
+	}
+
+	written, err := o.resource.WriteAt(b, off)
+	o.fhoffset += int64(written)
+	return written, err
+}
+
+func (o *GcsFile) Name() string {
+	return o.resource.name
+}
+
+func (o *GcsFile) readdir(count int) ([]*fileInfo, error) {
+	o.Sync()
+	//normSeparators should maybe not be here; adds
+	path := o.resource.fs.ensureTrailingSeparator(normSeparators(o.Name(), o.resource.fs.separator))
+	if o.ReadDirIt == nil {
+		//log.Printf("Querying path : %s\n", path)
+		o.ReadDirIt = o.resource.fs.bucket.Objects(
+			o.resource.ctx, &storage.Query{o.resource.fs.separator, path, false})
+	}
+	var res []*fileInfo
+	for {
+		object, err := o.ReadDirIt.Next()
+		if err == iterator.Done {
+			if len(res) > 0 || count <= 0 {
+				return res, nil
+			}
+			return res, io.EOF
+		}
+		if err != nil {
+			return res, err
+		}
+
+		tmp := fileInfo{object, o.resource.fs}
+
+		// Since we create "virtual folders which are empty objects they can sometimes be returned twice
+		// when we do a query (As the query will also return GCS version of "virtual folders" buy they only
+		// have a .Prefix, and not .Name)
+		if object.Name == "" {
+			continue
+		}
+
+		res = append(res, &tmp)
+		if count > 0 && len(res) >= count {
+			break
+		}
+	}
+	return res, nil
+}
+
+func (o *GcsFile) Readdir(count int) ([]os.FileInfo, error) {
+	fi, err := o.readdir(count)
+	if len(fi) > 0 {
+		sort.Sort(ByName(fi))
+	}
+
+	var res []os.FileInfo
+	for _, f := range fi {
+		res = append(res, f)
+	}
+	return res, err
+}
+
+func (o *GcsFile) Readdirnames(n int) ([]string, error) {
+	fi, err := o.Readdir(n)
+	if err != nil && err != io.EOF {
+		return nil, err
+	}
+	names := make([]string, len(fi))
+
+	for i, f := range fi {
+		names[i] = f.Name()
+	}
+	return names, err
+}
+
+func (o *GcsFile) Stat() (os.FileInfo, error) {
+	o.Sync()
+	objAttrs, err := o.resource.obj.Attrs(o.resource.ctx)
+	if err != nil {
+		if err.Error() == "storage: object doesn't exist" {
+			return nil, os.ErrNotExist //works with os.IsNotExist check
+		}
+		return nil, err
+	}
+	return &fileInfo{objAttrs, o.resource.fs}, nil
+}
+
+func (o *GcsFile) Sync() error {
+	return o.resource.maybeCloseIo()
+}
+
+func (o *GcsFile) Truncate(wantedSize int64) error {
+	if o.closed {
+		return ErrFileClosed
+	}
+	if o.openFlags == os.O_RDONLY {
+		return fmt.Errorf("File is opend as read only")
+	}
+	return o.resource.Truncate(wantedSize)
+}
+
+func (o *GcsFile) WriteString(s string) (ret int, err error) {
+	return o.Write([]byte(s))
+}