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07e5c38361
The only use cases in the code were in errors.IsFatal, backend/b2, which needs a workaround, and backend.ParseLayout. The last of these requires all backends to implement error unwrapping in IsNotExist. All backends except gs already did that.
405 lines
9.7 KiB
Go
405 lines
9.7 KiB
Go
package b2
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import (
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"context"
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"hash"
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"io"
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"net/http"
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"path"
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"sync"
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"time"
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"github.com/restic/restic/internal/backend"
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"github.com/restic/restic/internal/backend/sema"
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"github.com/restic/restic/internal/debug"
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"github.com/restic/restic/internal/errors"
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"github.com/restic/restic/internal/restic"
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"github.com/cenkalti/backoff/v4"
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"github.com/kurin/blazer/b2"
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)
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// b2Backend is a backend which stores its data on Backblaze B2.
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type b2Backend struct {
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client *b2.Client
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bucket *b2.Bucket
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cfg Config
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listMaxItems int
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backend.Layout
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sem sema.Semaphore
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}
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// Billing happens in 1000 item granlarity, but we are more interested in reducing the number of network round trips
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const defaultListMaxItems = 10 * 1000
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// ensure statically that *b2Backend implements restic.Backend.
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var _ restic.Backend = &b2Backend{}
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type sniffingRoundTripper struct {
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sync.Mutex
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lastErr error
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http.RoundTripper
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}
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func (s *sniffingRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
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res, err := s.RoundTripper.RoundTrip(req)
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if err != nil {
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s.Lock()
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s.lastErr = err
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s.Unlock()
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}
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return res, err
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}
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func newClient(ctx context.Context, cfg Config, rt http.RoundTripper) (*b2.Client, error) {
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sniffer := &sniffingRoundTripper{RoundTripper: rt}
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opts := []b2.ClientOption{b2.Transport(sniffer)}
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// if the connection B2 fails, this can cause the client to hang
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// cancel the connection after a minute to at least provide some feedback to the user
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ctx, cancel := context.WithTimeout(ctx, time.Minute)
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defer cancel()
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c, err := b2.NewClient(ctx, cfg.AccountID, cfg.Key.Unwrap(), opts...)
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if err == context.DeadlineExceeded {
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if sniffer.lastErr != nil {
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return nil, sniffer.lastErr
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}
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return nil, errors.New("connection to B2 failed")
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} else if err != nil {
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return nil, errors.Wrap(err, "b2.NewClient")
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}
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return c, nil
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}
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// Open opens a connection to the B2 service.
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func Open(ctx context.Context, cfg Config, rt http.RoundTripper) (restic.Backend, error) {
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debug.Log("cfg %#v", cfg)
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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client, err := newClient(ctx, cfg, rt)
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if err != nil {
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return nil, err
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}
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bucket, err := client.Bucket(ctx, cfg.Bucket)
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if err != nil {
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return nil, errors.Wrap(err, "Bucket")
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}
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sem, err := sema.New(cfg.Connections)
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if err != nil {
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return nil, err
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}
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be := &b2Backend{
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client: client,
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bucket: bucket,
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cfg: cfg,
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Layout: &backend.DefaultLayout{
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Join: path.Join,
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Path: cfg.Prefix,
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},
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listMaxItems: defaultListMaxItems,
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sem: sem,
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}
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return be, nil
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}
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// Create opens a connection to the B2 service. If the bucket does not exist yet,
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// it is created.
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func Create(ctx context.Context, cfg Config, rt http.RoundTripper) (restic.Backend, error) {
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debug.Log("cfg %#v", cfg)
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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client, err := newClient(ctx, cfg, rt)
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if err != nil {
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return nil, err
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}
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attr := b2.BucketAttrs{
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Type: b2.Private,
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}
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bucket, err := client.NewBucket(ctx, cfg.Bucket, &attr)
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if err != nil {
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return nil, errors.Wrap(err, "NewBucket")
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}
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sem, err := sema.New(cfg.Connections)
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if err != nil {
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return nil, err
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}
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be := &b2Backend{
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client: client,
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bucket: bucket,
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cfg: cfg,
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Layout: &backend.DefaultLayout{
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Join: path.Join,
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Path: cfg.Prefix,
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},
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listMaxItems: defaultListMaxItems,
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sem: sem,
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}
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present, err := be.Test(ctx, restic.Handle{Type: restic.ConfigFile})
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if err != nil {
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return nil, err
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}
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if present {
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return nil, errors.New("config already exists")
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}
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return be, nil
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}
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// SetListMaxItems sets the number of list items to load per request.
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func (be *b2Backend) SetListMaxItems(i int) {
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be.listMaxItems = i
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}
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func (be *b2Backend) Connections() uint {
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return be.cfg.Connections
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}
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// Location returns the location for the backend.
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func (be *b2Backend) Location() string {
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return be.cfg.Bucket
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}
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// Hasher may return a hash function for calculating a content hash for the backend
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func (be *b2Backend) Hasher() hash.Hash {
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return nil
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}
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// HasAtomicReplace returns whether Save() can atomically replace files
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func (be *b2Backend) HasAtomicReplace() bool {
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return true
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}
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// IsNotExist returns true if the error is caused by a non-existing file.
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func (be *b2Backend) IsNotExist(err error) bool {
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// blazer/b2 does not export its error types and values,
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// so we can't use errors.{As,Is}.
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for ; err != nil; err = errors.Unwrap(err) {
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if b2.IsNotExist(err) {
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return true
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}
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}
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return false
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}
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// Load runs fn with a reader that yields the contents of the file at h at the
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// given offset.
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func (be *b2Backend) Load(ctx context.Context, h restic.Handle, length int, offset int64, fn func(rd io.Reader) error) error {
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return backend.DefaultLoad(ctx, h, length, offset, be.openReader, fn)
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}
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func (be *b2Backend) openReader(ctx context.Context, h restic.Handle, length int, offset int64) (io.ReadCloser, error) {
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debug.Log("Load %v, length %v, offset %v from %v", h, length, offset, be.Filename(h))
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if err := h.Valid(); err != nil {
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return nil, backoff.Permanent(err)
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}
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if offset < 0 {
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return nil, errors.New("offset is negative")
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}
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if length < 0 {
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return nil, errors.Errorf("invalid length %d", length)
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}
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ctx, cancel := context.WithCancel(ctx)
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be.sem.GetToken()
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name := be.Layout.Filename(h)
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obj := be.bucket.Object(name)
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if offset == 0 && length == 0 {
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rd := obj.NewReader(ctx)
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return be.sem.ReleaseTokenOnClose(rd, cancel), nil
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}
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// pass a negative length to NewRangeReader so that the remainder of the
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// file is read.
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if length == 0 {
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length = -1
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}
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rd := obj.NewRangeReader(ctx, offset, int64(length))
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return be.sem.ReleaseTokenOnClose(rd, cancel), nil
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}
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// Save stores data in the backend at the handle.
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func (be *b2Backend) Save(ctx context.Context, h restic.Handle, rd restic.RewindReader) error {
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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if err := h.Valid(); err != nil {
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return backoff.Permanent(err)
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}
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be.sem.GetToken()
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defer be.sem.ReleaseToken()
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name := be.Filename(h)
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debug.Log("Save %v, name %v", h, name)
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obj := be.bucket.Object(name)
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// b2 always requires sha1 checksums for uploaded file parts
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w := obj.NewWriter(ctx)
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n, err := io.Copy(w, rd)
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debug.Log(" saved %d bytes, err %v", n, err)
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if err != nil {
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_ = w.Close()
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return errors.Wrap(err, "Copy")
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}
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// sanity check
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if n != rd.Length() {
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return errors.Errorf("wrote %d bytes instead of the expected %d bytes", n, rd.Length())
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}
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return errors.Wrap(w.Close(), "Close")
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}
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// Stat returns information about a blob.
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func (be *b2Backend) Stat(ctx context.Context, h restic.Handle) (bi restic.FileInfo, err error) {
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debug.Log("Stat %v", h)
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be.sem.GetToken()
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defer be.sem.ReleaseToken()
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name := be.Filename(h)
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obj := be.bucket.Object(name)
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info, err := obj.Attrs(ctx)
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if err != nil {
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debug.Log("Attrs() err %v", err)
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return restic.FileInfo{}, errors.Wrap(err, "Stat")
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}
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return restic.FileInfo{Size: info.Size, Name: h.Name}, nil
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}
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// Test returns true if a blob of the given type and name exists in the backend.
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func (be *b2Backend) Test(ctx context.Context, h restic.Handle) (bool, error) {
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debug.Log("Test %v", h)
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be.sem.GetToken()
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defer be.sem.ReleaseToken()
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found := false
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name := be.Filename(h)
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obj := be.bucket.Object(name)
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info, err := obj.Attrs(ctx)
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if err == nil && info != nil && info.Status == b2.Uploaded {
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found = true
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}
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return found, nil
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}
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// Remove removes the blob with the given name and type.
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func (be *b2Backend) Remove(ctx context.Context, h restic.Handle) error {
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debug.Log("Remove %v", h)
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be.sem.GetToken()
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defer be.sem.ReleaseToken()
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// the retry backend will also repeat the remove method up to 10 times
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for i := 0; i < 3; i++ {
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obj := be.bucket.Object(be.Filename(h))
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err := obj.Delete(ctx)
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if err == nil {
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// keep deleting until we are sure that no leftover file versions exist
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continue
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}
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// consider a file as removed if b2 informs us that it does not exist
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if b2.IsNotExist(err) {
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return nil
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}
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return errors.Wrap(err, "Delete")
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}
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return errors.New("failed to delete all file versions")
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}
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type semLocker struct {
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sema.Semaphore
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}
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func (sm *semLocker) Lock() { sm.GetToken() }
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func (sm *semLocker) Unlock() { sm.ReleaseToken() }
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// List returns a channel that yields all names of blobs of type t.
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func (be *b2Backend) List(ctx context.Context, t restic.FileType, fn func(restic.FileInfo) error) error {
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debug.Log("List %v", t)
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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prefix, _ := be.Basedir(t)
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iter := be.bucket.List(ctx, b2.ListPrefix(prefix), b2.ListPageSize(be.listMaxItems), b2.ListLocker(&semLocker{be.sem}))
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for iter.Next() {
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obj := iter.Object()
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attrs, err := obj.Attrs(ctx)
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if err != nil {
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return err
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}
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fi := restic.FileInfo{
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Name: path.Base(obj.Name()),
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Size: attrs.Size,
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}
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if err := fn(fi); err != nil {
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return err
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}
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}
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if err := iter.Err(); err != nil {
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debug.Log("List: %v", err)
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return err
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}
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return nil
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}
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// Remove keys for a specified backend type.
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func (be *b2Backend) removeKeys(ctx context.Context, t restic.FileType) error {
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debug.Log("removeKeys %v", t)
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return be.List(ctx, t, func(fi restic.FileInfo) error {
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return be.Remove(ctx, restic.Handle{Type: t, Name: fi.Name})
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})
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}
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// Delete removes all restic keys in the bucket. It will not remove the bucket itself.
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func (be *b2Backend) Delete(ctx context.Context) error {
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alltypes := []restic.FileType{
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restic.PackFile,
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restic.KeyFile,
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restic.LockFile,
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restic.SnapshotFile,
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restic.IndexFile}
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for _, t := range alltypes {
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err := be.removeKeys(ctx, t)
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if err != nil {
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return nil
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}
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}
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err := be.Remove(ctx, restic.Handle{Type: restic.ConfigFile})
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if err != nil && be.IsNotExist(err) {
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err = nil
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}
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return err
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}
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// Close does nothing
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func (be *b2Backend) Close() error { return nil }
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