93 lines
2.8 KiB
Go
93 lines
2.8 KiB
Go
package httputils
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import (
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"fmt"
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"io"
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"net/http"
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"time"
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"github.com/docker/docker/pkg/log"
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)
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type resumableRequestReader struct {
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client *http.Client
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request *http.Request
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lastRange int64
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totalSize int64
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currentResponse *http.Response
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failures uint32
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maxFailures uint32
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}
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// ResumableRequestReader makes it possible to resume reading a request's body transparently
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// maxfail is the number of times we retry to make requests again (not resumes)
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// totalsize is the total length of the body; auto detect if not provided
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func ResumableRequestReader(c *http.Client, r *http.Request, maxfail uint32, totalsize int64) io.ReadCloser {
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return &resumableRequestReader{client: c, request: r, maxFailures: maxfail, totalSize: totalsize}
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}
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func ResumableRequestReaderWithInitialResponse(c *http.Client, r *http.Request, maxfail uint32, totalsize int64, initialResponse *http.Response) io.ReadCloser {
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return &resumableRequestReader{client: c, request: r, maxFailures: maxfail, totalSize: totalsize, currentResponse: initialResponse}
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}
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func (r *resumableRequestReader) Read(p []byte) (n int, err error) {
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if r.client == nil || r.request == nil {
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return 0, fmt.Errorf("client and request can't be nil\n")
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}
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isFreshRequest := false
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if r.lastRange != 0 && r.currentResponse == nil {
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readRange := fmt.Sprintf("bytes=%d-%d", r.lastRange, r.totalSize)
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r.request.Header.Set("Range", readRange)
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time.Sleep(5 * time.Second)
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}
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if r.currentResponse == nil {
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r.currentResponse, err = r.client.Do(r.request)
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isFreshRequest = true
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}
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if err != nil && r.failures+1 != r.maxFailures {
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r.cleanUpResponse()
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r.failures++
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time.Sleep(5 * time.Duration(r.failures) * time.Second)
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return 0, nil
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} else if err != nil {
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r.cleanUpResponse()
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return 0, err
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}
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if r.currentResponse.StatusCode == 416 && r.lastRange == r.totalSize && r.currentResponse.ContentLength == 0 {
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r.cleanUpResponse()
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return 0, io.EOF
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} else if r.currentResponse.StatusCode != 206 && r.lastRange != 0 && isFreshRequest {
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r.cleanUpResponse()
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return 0, fmt.Errorf("the server doesn't support byte ranges")
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}
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if r.totalSize == 0 {
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r.totalSize = r.currentResponse.ContentLength
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} else if r.totalSize <= 0 {
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r.cleanUpResponse()
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return 0, fmt.Errorf("failed to auto detect content length")
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}
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n, err = r.currentResponse.Body.Read(p)
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r.lastRange += int64(n)
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if err != nil {
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r.cleanUpResponse()
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}
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if err != nil && err != io.EOF {
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log.Infof("encountered error during pull and clearing it before resume: %s", err)
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err = nil
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}
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return n, err
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}
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func (r *resumableRequestReader) Close() error {
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r.cleanUpResponse()
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r.client = nil
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r.request = nil
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return nil
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}
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func (r *resumableRequestReader) cleanUpResponse() {
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if r.currentResponse != nil {
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r.currentResponse.Body.Close()
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r.currentResponse = nil
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}
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}
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