1 // Copyright 2021 The Sigstore Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); 4 // you may not use this file except in compliance with the License. 5 // You may obtain a copy of the License at 6 // 7 // http://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, 11 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12 // See the License for the specific language governing permissions and 13 // limitations under the License. 14 15 package remote 16 17 import ( 18 "github.com/google/go-containerregistry/pkg/name" 19 ) 20 21 // ResolveDigest returns the digest of the image at the reference. 22 // 23 // If the reference is by digest already, it simply extracts the digest. 24 // Otherwise, it looks up the digest from the registry. 25 func ResolveDigest(ref name.Reference, opts ...Option) (name.Digest, error) { 26 o := makeOptions(ref.Context(), opts...) 27 if d, ok := ref.(name.Digest); ok { 28 return d, nil 29 } 30 desc, err := remoteGet(ref, o.ROpt...) 31 if err != nil { 32 return name.Digest{}, err 33 } 34 return ref.Context().Digest(desc.Digest.String()), nil 35 } 36