func()

in proxy/proxyserver/preheat.go [89:121]

• 29 lines of code
• 8 McCabe index (conditional complexity)

func (ph *PreheatHandler) fetchManifest(repo, digest string) (distribution.Manifest, error) {
	d, err := core.ParseSHA256Digest(digest)
	if err != nil {
		return nil, fmt.Errorf("Error parse digest: %s ", err)
	}

	buf := &bytes.Buffer{}
	// there may be a gap between registry finish uploading manifest and send notification.
	// see https://github.com/docker/distribution/issues/2625.
	interval := 100 * time.Millisecond
	for i := 0; i < 4; i++ {
		if i != 0 {
			time.Sleep(interval)
			interval = interval * 2
		}
		if err := ph.clusterClient.DownloadBlob(repo, d, buf); err == nil {
			break
		} else if err == blobclient.ErrBlobNotFound {
			continue
		} else {
			return nil, fmt.Errorf("download manifest: %s", err)
		}
	}
	if buf.Len() == 0 {
		return nil, fmt.Errorf("manifest not found")
	}

	manifest, _, err := dockerutil.ParseManifest(buf)
	if err != nil {
		return nil, fmt.Errorf("parse manifest: %s", err)
	}
	return manifest, nil
}