Agent 326: Fix releaseImage mirror handling with unit test

Based on #6272, this
fixes the mirror generation to handle release images that
include the sha256 checksum, e.g:
quay.io/openshift-release-dev/ocp-release@sha256:300bce8246cf880e792e106607925de0a404484637627edf5f517375517d54a4

Author: bfournie

pkg/asset/agent/image/ignition.go

@@ -6,6 +6,7 @@ import (
 	"net/url"
 	"path"
 	"path/filepath"
+	"regexp"
 	"strings"
 
 	"github.com/coreos/ignition/v2/config/util"
@@ -139,15 +140,7 @@ func (a *Ignition) Generate(dependencies asset.Parents) error {
 	registryCABundle := &mirror.CaBundle{}
 	dependencies.Get(registriesConfig, registryCABundle)
 
-	// Get the mirror for release image
-	releaseImageMirror := ""
-	source := strings.Split(agentManifests.ClusterImageSet.Spec.ReleaseImage, ":")
-	for _, config := range registriesConfig.MirrorConfig {
-		if config.Location == source[0] {
-			// include the tag with the build release image
-			releaseImageMirror = fmt.Sprintf("%s:%s", config.Mirror, source[1])
-		}
-	}
+	releaseImageMirror := getMirrorFromRelease(agentManifests.ClusterImageSet.Spec.ReleaseImage, registriesConfig)
 
 	infraEnvID := uuid.New().String()
 	logrus.Debug("Generated random infra-env id ", infraEnvID)
@@ -387,3 +380,22 @@ func RetrieveRendezvousIP(agentConfig *agent.Config, nmStateConfigs []*v1beta1.N
 	}
 	return rendezvousIP, err
 }
+
+func getMirrorFromRelease(releaseImage string, registriesConfig *mirror.RegistriesConf) string {
+
+	releaseImageMirror := ""
+	source := regexp.MustCompile(`^(.+?)(@sha256)?:(.+)`).FindStringSubmatch(releaseImage)
+	for _, config := range registriesConfig.MirrorConfig {
+		if config.Location == source[1] {
+			// include the tag with the build release image
+			if len(source) == 4 {
+				// Has Sha256
+				releaseImageMirror = fmt.Sprintf("%s%s:%s", config.Mirror, source[2], source[3])
+			} else if len(source) == 3 {
+				releaseImageMirror = fmt.Sprintf("%s:%s", config.Mirror, source[2])
+			}
+		}
+	}
+
+	return releaseImageMirror
+}

pkg/asset/agent/image/ignition_test.go

@@ -414,3 +414,84 @@ func buildIgnitionAssetDefaultDependencies() []asset.Asset {
 		&tls.AdminKubeConfigClientCertKey{},
 	}
 }
+
+func TestIgnition_getMirrorFromRelease(t *testing.T) {
+
+	cases := []struct {
+		name           string
+		release        string
+		registriesConf mirror.RegistriesConf
+		expectedMirror string
+	}{
+		{
+			name:           "no-mirror",
+			release:        "registry.ci.openshift.org/ocp/release:latest",
+			registriesConf: mirror.RegistriesConf{},
+			expectedMirror: "",
+		},
+		{
+			name:    "mirror-no-match",
+			release: "registry.ci.openshift.org/ocp/release:4.11.0-0.nightly-foo",
+			registriesConf: mirror.RegistriesConf{
+				File: &asset.File{
+					Filename: "registries.conf",
+					Data:     []byte(""),
+				},
+				MirrorConfig: []mirror.RegistriesConfig{
+					{
+						Location: "some.registry.org/release",
+						Mirror:   "some.mirror.org",
+					},
+				},
+			},
+			expectedMirror: "",
+		},
+		{
+			name:    "mirror-match",
+			release: "registry.ci.openshift.org/ocp/release:4.11.0-0.nightly-foo",
+			registriesConf: mirror.RegistriesConf{
+				File: &asset.File{
+					Filename: "registries.conf",
+					Data:     []byte(""),
+				},
+				MirrorConfig: []mirror.RegistriesConfig{
+					{
+						Location: "registry.ci.openshift.org/ocp/release",
+						Mirror:   "virthost.ostest.test.metalkube.org:5000/localimages/local-release-image",
+					},
+				},
+			},
+			expectedMirror: "virthost.ostest.test.metalkube.org:5000/localimages/local-release-image:4.11.0-0.nightly-foo",
+		},
+		{
+			name:    "mirror-match-with-checksum",
+			release: "quay.io/openshift-release-dev/ocp-release@sha256:300bce8246cf880e792e106607925de0a404484637627edf5f517375517d54a4",
+			registriesConf: mirror.RegistriesConf{
+				File: &asset.File{
+					Filename: "registries.conf",
+					Data:     []byte(""),
+				},
+				MirrorConfig: []mirror.RegistriesConfig{
+					{
+						Location: "quay.io/openshift-release-dev/ocp-v4.0-art-dev",
+						Mirror:   "localhost:5000/openshift4/openshift/release",
+					},
+					{
+						Location: "quay.io/openshift-release-dev/ocp-release",
+						Mirror:   "localhost:5000/openshift-release-dev/ocp-release",
+					},
+				},
+			},
+			expectedMirror: "localhost:5000/openshift-release-dev/ocp-release@sha256:300bce8246cf880e792e106607925de0a404484637627edf5f517375517d54a4",
+		},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+
+			mirror := getMirrorFromRelease(tc.release, &tc.registriesConf)
+
+			assert.Equal(t, tc.expectedMirror, mirror)
+
+		})
+	}
+}