Expand ${...} image tags using availableVersions

pkg/lib/image.go

@@ -20,6 +20,7 @@ import (
 	"io"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 
@@ -119,11 +120,16 @@ func mapChartImages(rootDir string, values map[string]string, sh *shell.Session,
 	}
 }
 
+// placeholderRE matches a shell-style ${...} template placeholder.
+var placeholderRE = regexp.MustCompile(`\$\{[^}]*\}`)
+
 func collectImages(obj map[string]any, images map[string]string, srcGK string) {
 	for k, v := range obj {
 		if k == "image" {
 			if s, ok := v.(string); ok && strings.ContainsRune(s, ':') {
-				images[s] = srcGK
+				for _, img := range expandVersionedImage(s, obj) {
+					images[img] = srcGK
+				}
 			}
 		} else if m, ok := v.(map[string]any); ok {
 			collectImages(m, images, srcGK)
@@ -137,6 +143,34 @@ func collectImages(obj map[string]any, images map[string]string, srcGK string) {
 	}
 }
 
+// expandVersionedImage expands a ${...} placeholder in an image reference using
+// the sibling "availableVersions" list found on the same object (kubestash addon
+// Function resources carry a "v0.29.0_${DB_VERSION}"-style tag alongside the list
+// of versions the image is published for). If the reference has no placeholder,
+// or no usable availableVersions is present, it is returned unchanged; unexpanded
+// placeholders are dropped later by ListImages/GroupImages.
+func expandVersionedImage(image string, obj map[string]any) []string {
+	if !placeholderRE.MatchString(image) {
+		return []string{image}
+	}
+
+	versions, ok := obj["availableVersions"].([]any)
+	if !ok || len(versions) == 0 {
+		return []string{image}
+	}
+
+	out := make([]string, 0, len(versions))
+	for _, v := range versions {
+		if ver, ok := v.(string); ok {
+			out = append(out, placeholderRE.ReplaceAllString(image, ver))
+		}
+	}
+	if len(out) == 0 {
+		return []string{image}
+	}
+	return out
+}
+
 func GroupImages(images map[string]string) map[string][]string {
 	result := map[string][]string{}
 	for img, srcGK := range images {

pkg/lib/image_test.go

@@ -0,0 +1,103 @@
+/*
+Copyright AppsCode Inc. and Contributors
+
+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 lib
+
+import (
+	"sort"
+	"testing"
+)
+
+func TestCollectImagesExpandsVersionedImage(t *testing.T) {
+	// Shape of a rendered kubestash addons.kubestash.com/v1alpha1 Function.
+	fn := map[string]any{
+		"spec": map[string]any{
+			"availableVersions": []any{"16.4", "17.2", "18.2"},
+			"image":             "ghcr.io/kubedb/postgres-restic-plugin:v0.29.0_${DB_VERSION}",
+			"args": []any{
+				"physical-restore",
+				"--namespace=${namespace:=default}",
+			},
+		},
+	}
+
+	images := map[string]string{}
+	collectImages(fn, images, "Function.addons.kubestash.com")
+
+	got := make([]string, 0, len(images))
+	for img := range images {
+		got = append(got, img)
+	}
+	sort.Strings(got)
+
+	want := []string{
+		"ghcr.io/kubedb/postgres-restic-plugin:v0.29.0_16.4",
+		"ghcr.io/kubedb/postgres-restic-plugin:v0.29.0_17.2",
+		"ghcr.io/kubedb/postgres-restic-plugin:v0.29.0_18.2",
+	}
+	if len(got) != len(want) {
+		t.Fatalf("expected %d images, got %d: %v", len(want), len(got), got)
+	}
+	for i := range want {
+		if got[i] != want[i] {
+			t.Errorf("image[%d] = %q, want %q", i, got[i], want[i])
+		}
+	}
+}
+
+func TestExpandVersionedImage(t *testing.T) {
+	cases := []struct {
+		name  string
+		image string
+		obj   map[string]any
+		want  []string
+	}{
+		{
+			name:  "no placeholder returned unchanged",
+			image: "ghcr.io/kubedb/postgres-restic-plugin:v0.29.0",
+			obj:   map[string]any{"availableVersions": []any{"16.4"}},
+			want:  []string{"ghcr.io/kubedb/postgres-restic-plugin:v0.29.0"},
+		},
+		{
+			name:  "placeholder but no availableVersions kept as-is",
+			image: "repo/img:v1_${DB_VERSION}",
+			obj:   map[string]any{},
+			want:  []string{"repo/img:v1_${DB_VERSION}"},
+		},
+		{
+			name:  "generic placeholder expanded",
+			image: "repo/img:${VER}",
+			obj:   map[string]any{"availableVersions": []any{"1.0", "2.0"}},
+			want:  []string{"repo/img:1.0", "repo/img:2.0"},
+		},
+	}
+
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			got := expandVersionedImage(tc.image, tc.obj)
+			sort.Strings(got)
+			sort.Strings(tc.want)
+			if len(got) != len(tc.want) {
+				t.Fatalf("got %v, want %v", got, tc.want)
+			}
+			for i := range tc.want {
+				if got[i] != tc.want[i] {
+					t.Errorf("got[%d] = %q, want %q", i, got[i], tc.want[i])
+				}
+			}
+		})
+	}
+}