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mirror of https://github.com/octoleo/restic.git synced 2024-12-23 11:28:54 +00:00
restic/internal/backend/b2/b2.go
2017-07-24 17:43:32 +02:00

378 lines
8.0 KiB
Go

package b2
import (
"context"
"io"
"path"
"strings"
"github.com/restic/restic/internal/backend"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/restic"
"github.com/kurin/blazer/b2"
)
// b2Backend is a backend which stores its data on Backblaze B2.
type b2Backend struct {
client *b2.Client
bucket *b2.Bucket
cfg Config
backend.Layout
sem *backend.Semaphore
}
// ensure statically that *b2Backend implements restic.Backend.
var _ restic.Backend = &b2Backend{}
func newClient(ctx context.Context, cfg Config) (*b2.Client, error) {
opts := []b2.ClientOption{b2.Transport(backend.Transport())}
c, err := b2.NewClient(ctx, cfg.AccountID, cfg.Key, opts...)
if err != nil {
return nil, errors.Wrap(err, "b2.NewClient")
}
return c, nil
}
// Open opens a connection to the B2 service.
func Open(cfg Config) (restic.Backend, error) {
debug.Log("cfg %#v", cfg)
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
client, err := newClient(ctx, cfg)
if err != nil {
return nil, err
}
bucket, err := client.Bucket(ctx, cfg.Bucket)
if err != nil {
return nil, errors.Wrap(err, "Bucket")
}
sem, err := backend.NewSemaphore(cfg.Connections)
if err != nil {
return nil, err
}
be := &b2Backend{
client: client,
bucket: bucket,
cfg: cfg,
Layout: &backend.DefaultLayout{
Join: path.Join,
Path: cfg.Prefix,
},
sem: sem,
}
return be, nil
}
// Create opens a connection to the B2 service. If the bucket does not exist yet,
// it is created.
func Create(cfg Config) (restic.Backend, error) {
debug.Log("cfg %#v", cfg)
ctx, cancel := context.WithCancel(context.TODO())
defer cancel()
client, err := newClient(ctx, cfg)
if err != nil {
return nil, err
}
attr := b2.BucketAttrs{
Type: b2.Private,
}
bucket, err := client.NewBucket(ctx, cfg.Bucket, &attr)
if err != nil {
return nil, errors.Wrap(err, "NewBucket")
}
sem, err := backend.NewSemaphore(cfg.Connections)
if err != nil {
return nil, err
}
be := &b2Backend{
client: client,
bucket: bucket,
cfg: cfg,
Layout: &backend.DefaultLayout{
Join: path.Join,
Path: cfg.Prefix,
},
sem: sem,
}
present, err := be.Test(context.TODO(), restic.Handle{Type: restic.ConfigFile})
if err != nil {
return nil, err
}
if present {
return nil, errors.New("config already exists")
}
return be, nil
}
// Location returns the location for the backend.
func (be *b2Backend) Location() string {
return be.cfg.Bucket
}
// wrapReader wraps an io.ReadCloser to run an additional function on Close.
type wrapReader struct {
io.ReadCloser
eofSeen bool
f func()
}
func (wr *wrapReader) Read(p []byte) (int, error) {
if wr.eofSeen {
return 0, io.EOF
}
n, err := wr.ReadCloser.Read(p)
if err == io.EOF {
wr.eofSeen = true
}
return n, err
}
func (wr *wrapReader) Close() error {
err := wr.ReadCloser.Close()
wr.f()
return err
}
// IsNotExist returns true if the error is caused by a non-existing file.
func (be *b2Backend) IsNotExist(err error) bool {
return b2.IsNotExist(errors.Cause(err))
}
// Load returns the data stored in the backend for h at the given offset
// and saves it in p. Load has the same semantics as io.ReaderAt.
func (be *b2Backend) Load(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
debug.Log("Load %v, length %v, offset %v from %v", h, length, offset, be.Filename(h))
if err := h.Valid(); err != nil {
return nil, err
}
if offset < 0 {
return nil, errors.New("offset is negative")
}
if length < 0 {
return nil, errors.Errorf("invalid length %d", length)
}
ctx, cancel := context.WithCancel(ctx)
be.sem.GetToken()
name := be.Layout.Filename(h)
obj := be.bucket.Object(name)
if offset == 0 && length == 0 {
rd := obj.NewReader(ctx)
wrapper := &wrapReader{
ReadCloser: rd,
f: func() {
cancel()
be.sem.ReleaseToken()
},
}
return wrapper, nil
}
// pass a negative length to NewRangeReader so that the remainder of the
// file is read.
if length == 0 {
length = -1
}
rd := obj.NewRangeReader(ctx, offset, int64(length))
wrapper := &wrapReader{
ReadCloser: rd,
f: func() {
cancel()
be.sem.ReleaseToken()
},
}
return wrapper, nil
}
// Save stores data in the backend at the handle.
func (be *b2Backend) Save(ctx context.Context, h restic.Handle, rd io.Reader) (err error) {
ctx, cancel := context.WithCancel(ctx)
defer cancel()
if err := h.Valid(); err != nil {
return err
}
be.sem.GetToken()
defer be.sem.ReleaseToken()
name := be.Filename(h)
debug.Log("Save %v, name %v", h, name)
obj := be.bucket.Object(name)
_, err = obj.Attrs(ctx)
if err == nil {
debug.Log(" %v already exists", h)
return errors.New("key already exists")
}
w := obj.NewWriter(ctx)
n, err := io.Copy(w, rd)
debug.Log(" saved %d bytes, err %v", n, err)
if err != nil {
_ = w.Close()
return errors.Wrap(err, "Copy")
}
return errors.Wrap(w.Close(), "Close")
}
// Stat returns information about a blob.
func (be *b2Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) {
debug.Log("Stat %v", h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
name := be.Filename(h)
obj := be.bucket.Object(name)
info, err := obj.Attrs(ctx)
if err != nil {
debug.Log("Attrs() err %v", err)
return restic.FileInfo{}, errors.Wrap(err, "Stat")
}
return restic.FileInfo{Size: info.Size}, nil
}
// Test returns true if a blob of the given type and name exists in the backend.
func (be *b2Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
debug.Log("Test %v", h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
found := false
name := be.Filename(h)
obj := be.bucket.Object(name)
info, err := obj.Attrs(ctx)
if err == nil && info != nil && info.Status == b2.Uploaded {
found = true
}
return found, nil
}
// Remove removes the blob with the given name and type.
func (be *b2Backend) Remove(ctx context.Context, h restic.Handle) error {
debug.Log("Remove %v", h)
be.sem.GetToken()
defer be.sem.ReleaseToken()
obj := be.bucket.Object(be.Filename(h))
return errors.Wrap(obj.Delete(ctx), "Delete")
}
// List returns a channel that yields all names of blobs of type t. A
// goroutine is started for this. If the channel done is closed, sending
// stops.
func (be *b2Backend) List(ctx context.Context, t restic.FileType) <-chan string {
debug.Log("List %v", t)
ch := make(chan string)
ctx, cancel := context.WithCancel(ctx)
be.sem.GetToken()
go func() {
defer close(ch)
defer cancel()
defer be.sem.ReleaseToken()
prefix := be.Dirname(restic.Handle{Type: t})
cur := &b2.Cursor{Prefix: prefix}
for {
objs, c, err := be.bucket.ListCurrentObjects(ctx, 1000, cur)
if err != nil && err != io.EOF {
return
}
for _, obj := range objs {
// Skip objects returned that do not have the specified prefix.
if !strings.HasPrefix(obj.Name(), prefix) {
continue
}
m := path.Base(obj.Name())
if m == "" {
continue
}
select {
case ch <- m:
case <-ctx.Done():
return
}
}
if err == io.EOF {
return
}
cur = c
}
}()
return ch
}
// Remove keys for a specified backend type.
func (be *b2Backend) removeKeys(ctx context.Context, t restic.FileType) error {
debug.Log("removeKeys %v", t)
for key := range be.List(ctx, t) {
err := be.Remove(ctx, restic.Handle{Type: t, Name: key})
if err != nil {
return err
}
}
return nil
}
// Delete removes all restic keys in the bucket. It will not remove the bucket itself.
func (be *b2Backend) Delete(ctx context.Context) error {
alltypes := []restic.FileType{
restic.DataFile,
restic.KeyFile,
restic.LockFile,
restic.SnapshotFile,
restic.IndexFile}
for _, t := range alltypes {
err := be.removeKeys(ctx, t)
if err != nil {
return nil
}
}
err := be.Remove(ctx, restic.Handle{Type: restic.ConfigFile})
if err != nil && b2.IsNotExist(errors.Cause(err)) {
err = nil
}
return err
}
// Close does nothing
func (be *b2Backend) Close() error { return nil }