159 lines
2.7 KiB
Go
159 lines
2.7 KiB
Go
package client
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"io/ioutil"
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"net/http"
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"os"
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"github.com/docker/distribution"
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"github.com/docker/distribution/context"
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)
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type httpBlob struct {
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*repository
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desc distribution.Descriptor
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rc io.ReadCloser // remote read closer
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brd *bufio.Reader // internal buffered io
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offset int64
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err error
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}
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func (hb *httpBlob) Read(p []byte) (n int, err error) {
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if hb.err != nil {
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return 0, hb.err
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}
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rd, err := hb.reader()
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if err != nil {
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return 0, err
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}
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n, err = rd.Read(p)
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hb.offset += int64(n)
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// Simulate io.EOF error if we reach filesize.
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if err == nil && hb.offset >= hb.desc.Length {
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err = io.EOF
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}
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return n, err
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}
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func (hb *httpBlob) Seek(offset int64, whence int) (int64, error) {
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if hb.err != nil {
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return 0, hb.err
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}
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var err error
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newOffset := hb.offset
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switch whence {
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case os.SEEK_CUR:
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newOffset += int64(offset)
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case os.SEEK_END:
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newOffset = hb.desc.Length + int64(offset)
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case os.SEEK_SET:
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newOffset = int64(offset)
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}
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if newOffset < 0 {
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err = fmt.Errorf("cannot seek to negative position")
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} else {
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if hb.offset != newOffset {
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hb.reset()
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}
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// No problems, set the offset.
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hb.offset = newOffset
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}
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return hb.offset, err
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}
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func (hb *httpBlob) Close() error {
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if hb.err != nil {
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return hb.err
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}
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// close and release reader chain
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if hb.rc != nil {
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hb.rc.Close()
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}
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hb.rc = nil
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hb.brd = nil
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hb.err = fmt.Errorf("httpBlob: closed")
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return nil
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}
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func (hb *httpBlob) reset() {
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if hb.err != nil {
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return
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}
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if hb.rc != nil {
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hb.rc.Close()
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hb.rc = nil
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}
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}
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func (hb *httpBlob) reader() (io.Reader, error) {
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if hb.err != nil {
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return nil, hb.err
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}
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if hb.rc != nil {
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return hb.brd, nil
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}
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// If the offset is great than or equal to size, return a empty, noop reader.
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if hb.offset >= hb.desc.Length {
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return ioutil.NopCloser(bytes.NewReader([]byte{})), nil
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}
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blobURL, err := hb.ub.BuildBlobURL(hb.name, hb.desc.Digest)
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if err != nil {
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return nil, err
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}
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req, err := http.NewRequest("GET", blobURL, nil)
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if err != nil {
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return nil, err
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}
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if hb.offset > 0 {
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// TODO(stevvooe): Get this working correctly.
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// If we are at different offset, issue a range request from there.
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req.Header.Add("Range", fmt.Sprintf("1-"))
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context.GetLogger(hb.context).Infof("Range: %s", req.Header.Get("Range"))
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}
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resp, err := hb.client.Do(req)
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if err != nil {
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return nil, err
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}
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switch {
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case resp.StatusCode == 200:
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hb.rc = resp.Body
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default:
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defer resp.Body.Close()
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return nil, fmt.Errorf("unexpected status resolving reader: %v", resp.Status)
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}
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if hb.brd == nil {
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hb.brd = bufio.NewReader(hb.rc)
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} else {
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hb.brd.Reset(hb.rc)
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}
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return hb.brd, nil
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}
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