forked from google/go-containerregistry
/
check.go
59 lines (54 loc) · 1.98 KB
/
check.go
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package remote
import (
"context"
"fmt"
"net/http"
"github.com/google/go-containerregistry/pkg/authn"
"github.com/google/go-containerregistry/pkg/name"
"github.com/google/go-containerregistry/pkg/v1/remote/transport"
)
// CheckPushPermission returns an error if the given keychain cannot authorize
// a push operation to the given ref.
//
// This can be useful to check whether the caller has permission to push an
// image before doing work to construct the image.
//
// TODO(#412): Remove the need for this method.
func CheckPushPermission(ref name.Reference, kc authn.Keychain, t http.RoundTripper) error {
auth, err := kc.Resolve(ref.Context().Registry)
if err != nil {
return fmt.Errorf("resolving authorization for %v failed: %v", ref.Context().Registry, err)
}
scopes := []string{ref.Scope(transport.PushScope)}
tr, err := transport.New(ref.Context().Registry, auth, t, scopes)
if err != nil {
return fmt.Errorf("creating push check transport for %v failed: %v", ref.Context().Registry, err)
}
// TODO(jasonhall): Against GCR, just doing the token handshake is
// enough, but this doesn't extend to Dockerhub
// (https://github.com/docker/hub-feedback/issues/1771), so we actually
// need to initiate an upload to tell whether the credentials can
// authorize a push. Figure out how to return early here when we can,
// to avoid a roundtrip for spec-compliant registries.
w := writer{
repo: ref.Context(),
client: &http.Client{Transport: tr},
context: context.Background(),
}
loc, _, err := w.initiateUpload("", "")
if loc != "" {
// Since we're only initiating the upload to check whether we
// can, we should attempt to cancel it, in case initiating
// reserves some resources on the server. We shouldn't wait for
// cancelling to complete, and we don't care if it fails.
go w.cancelUpload(loc)
}
return err
}
func (w *writer) cancelUpload(loc string) {
req, err := http.NewRequest(http.MethodDelete, loc, nil)
if err != nil {
return
}
_, _ = w.client.Do(req)
}