Add a util library to parse container image name and data

util/container/image.go

@@ -0,0 +1,82 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package container
+
+import (
+	"fmt"
+	"path"
+
+	//  Import the crypto sha256 algorithm for the docker image parser to work
+	_ "crypto/sha256"
+	//  Import the crypto/sha512 algorithm for the docker image parser to work with 384 and 512 sha hashes
+	_ "crypto/sha512"
+
+	"github.com/docker/distribution/reference"
+	dockerref "github.com/docker/distribution/reference"
+)
+
+const (
+	// DefaultImageTag is the default tag for docker image.
+	DefaultImageTag = "latest"
+)
+
+// Image type represents the container image details
+type Image struct {
+	Repository string
+	Name       string
+	Tag        string
+	Digest     string
+}
+
+// ParseImageName parses a docker image string into three parts: repo, tag and digest.
+// If both tag and digest are empty, a default image tag will be returned.
+func ParseImageName(image string) (Image, error) {
+	named, err := dockerref.ParseNamed(image)
+	if err != nil {
+		return Image{}, fmt.Errorf("couldn't parse image name: %v", err)
+	}
+
+	var repo, tag, digest string
+	_, nameOnly := path.Split(reference.Path(named))
+	if nameOnly != "" {
+		repo = named.Name()[:len(named.Name())-len(nameOnly)-1]
+	}
+
+	tagged, ok := named.(dockerref.Tagged)
+	if ok {
+		tag = tagged.Tag()
+	}
+
+	digested, ok := named.(dockerref.Digested)
+	if ok {
+		digest = digested.Digest().String()
+	}
+
+	return Image{Repository: repo, Name: nameOnly, Tag: tag, Digest: digest}, nil
+}
+
+func (i Image) String() string {
+	// repo/name [ ":" tag ] [ "@" digest ]
+	ref := fmt.Sprintf("%s/%s", i.Repository, i.Name)
+	if i.Tag != "" {
+		ref = fmt.Sprintf("%s:%s", ref, i.Tag)
+	}
+	if i.Digest != "" {
+		ref = fmt.Sprintf("%s:%s", ref, i.Digest)
+	}
+	return ref
+}

util/container/image_test.go

@@ -0,0 +1,137 @@
+/*
+Copyright 2020 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package container
+
+import (
+	"testing"
+
+	. "github.com/onsi/gomega"
+)
+
+func TestParseImageName(t *testing.T) {
+	testCases := []struct {
+		name      string
+		input     string
+		repo      string
+		imageName string
+		tag       string
+		digest    string
+		wantError bool
+	}{
+		{
+			name:      "input with path and tag",
+			input:     "k8s.gcr.io/dev/coredns:1.6.2",
+			repo:      "k8s.gcr.io/dev",
+			imageName: "coredns",
+			tag:       "1.6.2",
+			wantError: false,
+		},
+		{
+			name:      "input with name only",
+			input:     "example.com/root",
+			repo:      "example.com",
+			imageName: "root",
+			wantError: false,
+		},
+		{
+			name:      "input with name and tag without path",
+			input:     "example.com/root:tag",
+			repo:      "example.com",
+			imageName: "root",
+			tag:       "tag",
+			wantError: false,
+		},
+		{
+			name:      "input with name and digest without tag",
+			input:     "example.com/root@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			repo:      "example.com",
+			imageName: "root",
+			digest:    "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			wantError: false,
+		},
+		{
+			name:      "input with path and name",
+			input:     "example.com/user/repo",
+			repo:      "example.com/user",
+			imageName: "repo",
+			wantError: false,
+		},
+		{
+			name:      "input with path, anme and tag",
+			input:     "example.com/user/repo:tag",
+			repo:      "example.com/user",
+			imageName: "repo",
+			tag:       "tag",
+			wantError: false,
+		},
+		{
+			name:      "input with path, name, tag and digest",
+			input:     "example.com/user/repo@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			repo:      "example.com/user",
+			imageName: "repo",
+			digest:    "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			wantError: false,
+		},
+		{
+			name:      "input with url with port",
+			input:     "url:5000/repo",
+			repo:      "url:5000",
+			imageName: "repo",
+			wantError: false,
+		},
+		{
+			name:      "input with url with port and tag",
+			input:     "url:5000/repo:tag",
+			repo:      "url:5000",
+			imageName: "repo",
+			tag:       "tag",
+			wantError: false,
+		},
+		{
+			name:      "input with url with port and digest",
+			input:     "url:5000/repo@sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			repo:      "url:5000",
+			imageName: "repo",
+			digest:    "sha256:e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855",
+			wantError: false,
+		},
+		{
+			name:      "input with invalid image name",
+			input:     "url$#",
+			repo:      "",
+			imageName: "",
+			tag:       "",
+			wantError: true,
+		},
+	}
+	for _, tc := range testCases {
+		g := NewWithT(t)
+
+		t.Run(tc.name, func(t *testing.T) {
+			image, err := ParseImageName(tc.input)
+			if tc.wantError {
+				g.Expect(err).To(HaveOccurred())
+			} else {
+				g.Expect(err).NotTo(HaveOccurred())
+			}
+			g.Expect(image.Repository).To(Equal(tc.repo))
+			g.Expect(image.Name).To(Equal(tc.imageName))
+			g.Expect(image.Tag).To(Equal(tc.tag))
+			g.Expect(image.Digest).To(Equal(tc.digest))
+		})
+	}
+}

util/util.go

@@ -40,6 +40,7 @@ import (
 	"k8s.io/apimachinery/pkg/runtime/schema"
 	"k8s.io/apimachinery/pkg/version"
 	clusterv1 "sigs.k8s.io/cluster-api/api/v1alpha3"
+	"sigs.k8s.io/cluster-api/util/container"
 	ctrl "sigs.k8s.io/controller-runtime"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
@@ -149,17 +150,16 @@ func ModifyImageTag(imageName, tagName string) (string, error) {
 
 // ModifyImageRepository takes an imageName (e.g., repository/image:tag), and returns an image name with updated repository
 func ModifyImageRepository(imageName, repositoryName string) (string, error) {
-	namedRef, err := reference.ParseNamed(imageName)
+	imageRef, err := container.ParseImageName(imageName)
 	if err != nil {
 		return "", errors.Wrap(err, "failed to parse image name")
 	}
-	_, nameOnly := path.Split(reference.Path(namedRef))
-	nameUpdated, err := reference.WithName(path.Join(repositoryName, nameOnly))
+	nameUpdated, err := reference.WithName(path.Join(repositoryName, imageRef.Name))
 	if err != nil {
 		return "", errors.Wrap(err, "failed to update repository name")
 	}
-	if tagged, ok := namedRef.(reference.NamedTagged); ok {
-		retagged, err := reference.WithTag(nameUpdated, tagged.Tag())
+	if imageRef.Tag != "" {
+		retagged, err := reference.WithTag(nameUpdated, imageRef.Tag)
 		if err != nil {
 			// this shouldn't be possible since we parsed it already above
 			return "", errors.Wrap(err, "failed to parse image tag")