3dc2d849c7
- Set an Etag header
- Check If-None-Match and respond appropriately
- Set a Cache-Control header with a default of 1 week
Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
104 lines
2.6 KiB
Go
104 lines
2.6 KiB
Go
package storage
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import (
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"fmt"
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"net/http"
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"time"
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"github.com/docker/distribution"
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"github.com/docker/distribution/digest"
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"github.com/docker/distribution/registry/storage/driver"
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)
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// layerReader implements Layer and provides facilities for reading and
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// seeking.
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type layerReader struct {
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fileReader
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digest digest.Digest
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}
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// newLayerReader returns a new layerReader with the digest, path and length,
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// eliding round trips to the storage backend.
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func newLayerReader(driver driver.StorageDriver, dgst digest.Digest, path string, length int64) (*layerReader, error) {
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fr := &fileReader{
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driver: driver,
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path: path,
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size: length,
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}
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return &layerReader{
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fileReader: *fr,
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digest: dgst,
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}, nil
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}
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var _ distribution.Layer = &layerReader{}
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func (lr *layerReader) Digest() digest.Digest {
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return lr.digest
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}
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func (lr *layerReader) Length() int64 {
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return lr.size
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}
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func (lr *layerReader) CreatedAt() time.Time {
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return lr.modtime
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}
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// Close the layer. Should be called when the resource is no longer needed.
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func (lr *layerReader) Close() error {
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return lr.closeWithErr(distribution.ErrLayerClosed)
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}
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func (lr *layerReader) Handler(r *http.Request) (h http.Handler, err error) {
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var handlerFunc http.HandlerFunc
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redirectURL, err := lr.fileReader.driver.URLFor(lr.ctx, lr.path, map[string]interface{}{"method": r.Method})
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switch err {
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case nil:
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handlerFunc = func(w http.ResponseWriter, r *http.Request) {
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// Redirect to storage URL.
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http.Redirect(w, r, redirectURL, http.StatusTemporaryRedirect)
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}
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case driver.ErrUnsupportedMethod:
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handlerFunc = func(w http.ResponseWriter, r *http.Request) {
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// Fallback to serving the content directly.
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http.ServeContent(w, r, lr.digest.String(), lr.CreatedAt(), lr)
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}
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default:
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// Some unexpected error.
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return nil, err
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}
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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// If the registry is serving this content itself, check
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// the If-None-Match header and return 304 on match. Redirected
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// storage implementations do the same.
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if etagMatch(r, lr.digest.String()) {
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w.WriteHeader(http.StatusNotModified)
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return
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}
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setCacheHeaders(w, 86400, lr.digest.String())
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w.Header().Set("Docker-Content-Digest", lr.digest.String())
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handlerFunc.ServeHTTP(w, r)
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}), nil
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}
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func etagMatch(r *http.Request, etag string) bool {
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for _, headerVal := range r.Header["If-None-Match"] {
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if headerVal == etag {
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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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func setCacheHeaders(w http.ResponseWriter, cacheAge int, etag string) {
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w.Header().Set("ETag", etag)
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w.Header().Set("Cache-Control", fmt.Sprintf("max-age=%d", cacheAge))
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}
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