forked from TrueCloudLab/restic
201 lines
4.1 KiB
Go
201 lines
4.1 KiB
Go
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package s3
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import (
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"bytes"
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"errors"
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"io"
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"strings"
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"sync"
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"github.com/mitchellh/goamz/aws"
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as3 "github.com/mitchellh/goamz/s3"
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"github.com/restic/restic/backend"
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)
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var ErrWrongData = errors.New("wrong data returned by backend, checksum does not match")
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func s3path(t backend.Type, name string) string {
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if t == backend.Config {
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return string(t)
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}
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return string(t) + "/" + name
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}
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type S3DB struct {
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bucket *as3.Bucket
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mput sync.Mutex
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path string
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}
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// Open opens the local backend at bucket and region.
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func Open(regionname, bucketname string) (*S3DB, error) {
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auth, err := aws.EnvAuth()
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if err != nil {
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return nil, err
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}
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client := as3.New(auth, aws.Regions[regionname])
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return &S3DB{bucket: client.Bucket(bucketname), path: bucketname}, nil
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}
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// Location returns this backend's location (the directory name).
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func (b *S3DB) Location() string {
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return b.path
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}
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type s3Blob struct {
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b *S3DB
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buf *bytes.Buffer
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final bool
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}
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func (bb *s3Blob) Write(p []byte) (int, error) {
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if bb.final {
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return 0, errors.New("blob already closed")
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}
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n, err := bb.buf.Write(p)
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return n, err
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}
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func (bb *s3Blob) Read(p []byte) (int, error) {
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return bb.buf.Read(p)
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}
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func (bb *s3Blob) Close() error {
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bb.final = true
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bb.buf.Reset()
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return nil
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}
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func (bb *s3Blob) Size() uint {
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return uint(bb.buf.Len())
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}
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func (bb *s3Blob) Finalize(t backend.Type, name string) error {
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if bb.final {
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return errors.New("Already finalized")
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}
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bb.final = true
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path := s3path(t, name)
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bb.b.mput.Lock()
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err := bb.b.bucket.Put(path, bb.buf.Bytes(), "binary/octet-stream", "private")
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bb.b.mput.Unlock()
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bb.buf.Reset()
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return err
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}
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// Create creates a new Blob. The data is available only after Finalize()
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// has been called on the returned Blob.
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func (b *S3DB) Create() (backend.Blob, error) {
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blob := s3Blob{
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b: b,
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buf: &bytes.Buffer{},
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}
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return &blob, nil
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}
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func (b *S3DB) get(t backend.Type, name string) (*s3Blob, error) {
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blob := &s3Blob{
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b: b,
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}
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path := s3path(t, name)
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data, err := b.bucket.Get(path)
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blob.buf = bytes.NewBuffer(data)
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return blob, err
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}
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// Get returns a reader that yields the content stored under the given
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// name. The reader should be closed after draining it.
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func (b *S3DB) Get(t backend.Type, name string) (io.ReadCloser, error) {
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return b.get(t, name)
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}
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// GetReader returns an io.ReadCloser for the Blob with the given name of
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// type t at offset and length. If length is 0, the reader reads until EOF.
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func (b *S3DB) GetReader(t backend.Type, name string, offset, length uint) (io.ReadCloser, error) {
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blob, err := b.get(t, name)
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if err != nil {
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return nil, err
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}
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blob.buf.Next(int(offset))
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if length == 0 {
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return blob, nil
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}
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return backend.LimitReadCloser(blob, int64(length)), 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 (b *S3DB) Test(t backend.Type, name string) (bool, error) {
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found := false
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path := s3path(t, name)
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key, err := b.bucket.GetKey(path)
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if err == nil && key.Key == path {
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found = true
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}
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// If error, then not found
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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 (b *S3DB) Remove(t backend.Type, name string) error {
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path := s3path(t, name)
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return b.bucket.Del(path)
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}
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// List returns a channel that yields all names of blobs of type t. A
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// goroutine is started for this. If the channel done is closed, sending
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// stops.
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func (b *S3DB) List(t backend.Type, done <-chan struct{}) <-chan string {
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ch := make(chan string)
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prefix := string(t) + "/"
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listresp, err := b.bucket.List(prefix, "/", "", 10000)
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if err != nil {
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close(ch)
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return ch
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}
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matches := make([]string, len(listresp.Contents))
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for idx, key := range listresp.Contents {
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matches[idx] = strings.TrimPrefix(key.Key, prefix)
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}
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go func() {
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defer close(ch)
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for _, m := range matches {
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if m == "" {
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continue
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}
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select {
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case ch <- m:
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case <-done:
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return
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}
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}
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}()
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return ch
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}
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// Delete removes the repository and all files.
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func (b *S3DB) Delete() error {
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return b.bucket.DelBucket()
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}
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// Close does nothing
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func (b *S3DB) Close() error { return nil }
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