Remove host name from sigstore paths

See a long meandering discussion in
containers/image#120 .

Note that the repo name within a single host is still used within the
signstore path, only the host name has been dropped.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

docker/lookaside.go

@@ -9,12 +9,12 @@ import (
 	"path/filepath"
 	"strings"
 
+	"github.com/Sirupsen/logrus"
+	"github.com/containers/image/docker/reference"
+	"github.com/containers/image/types"
 	"github.com/ghodss/yaml"
 	"github.com/opencontainers/go-digest"
 	"github.com/pkg/errors"
-
-	"github.com/Sirupsen/logrus"
-	"github.com/containers/image/types"
 )
 
 // systemRegistriesDirPath is the path to registries.d, used for locating lookaside Docker signature storage.
@@ -64,8 +64,8 @@ func configuredSignatureStorageBase(ctx *types.SystemContext, ref dockerReferenc
 		return nil, errors.Wrapf(err, "Invalid signature storage URL %s", topLevel)
 	}
 	// FIXME? Restrict to explicitly supported schemes?
-	repo := ref.ref.Name()        // Note that this is without a tag or digest.
-	if path.Clean(repo) != repo { // Coverage: This should not be reachable because /./ and /../ components are not valid in docker references
+	repo := reference.Path(ref.ref) // Note that this is without a tag or digest.
+	if path.Clean(repo) != repo {   // Coverage: This should not be reachable because /./ and /../ components are not valid in docker references
 		return nil, errors.Errorf("Unexpected path elements in Docker reference %s for signature storage", ref.ref.String())
 	}
 	url.Path = url.Path + "/" + repo

docker/lookaside_test.go

@@ -46,7 +46,7 @@ func TestConfiguredSignatureStorageBase(t *testing.T) {
 		dockerRefFromString(t, "//example.com/my/project"), false)
 	assert.NoError(t, err)
 	require.NotNil(t, base)
-	assert.Equal(t, "https://sigstore.example.com/example.com/my/project", (*url.URL)(base).String())
+	assert.Equal(t, "https://sigstore.example.com/my/project", (*url.URL)(base).String())
 }
 
 func TestRegistriesDirPath(t *testing.T) {