Add basic support for OCI registry based charts

.gitignore

@@ -7,3 +7,4 @@
 .idea
 *.DS_Store
 /fleet
+/.vscode

docs/gitrepo-structure.md

@@ -59,7 +59,8 @@ kustomize:
   dir: ./kustomize
 
 helm:
-  # Use a custom location for the Helm chart. This can refer to any go-getter URL.
+  # Use a custom location for the Helm chart. This can refer to any go-getter URL or
+  # OCI registry based helm chart URL e.g. "oci://ghcr.io/fleetrepoci/guestbook".
   # This allows one to download charts from most any location.  Also know that
   # go-getter URL supports adding a digest to validate the download. If repo
   # is set below this field is the name of the chart to lookup

e2e/assets/single-cluster/helm-oci.yaml

@@ -0,0 +1,16 @@
+kind: GitRepo
+apiVersion: fleet.cattle.io/v1alpha1
+metadata:
+  name: helm
+spec:
+  repo: https://github.com/rancher/fleet-examples
+  branch: add-helm-oci-example
+  paths:
+  - single-cluster/helm-oci
+  targets:
+  - clusterSelector:
+      matchExpressions:
+      - key: provider.cattle.io
+        operator: NotIn
+        values:
+        - harvester

e2e/single-cluster/single_cluster_test.go

@@ -32,6 +32,19 @@ var _ = Describe("Single Cluster Examples", func() {
 
 	})
 
+	Context("containing an oci based helm chart", func() {
+		BeforeEach(func() {
+			asset = "single-cluster/helm-oci.yaml"
+		})
+
+		It("deploys the helm chart", func() {
+			Eventually(func() string {
+				out, _ := k.Namespace("fleet-helm-oci-example").Get("pods")
+				return out
+			}, testenv.Timeout).Should(ContainSubstring("frontend-"))
+		})
+	})
+
 	When("creating a gitrepo resource", func() {
 		Context("containing a helm chart", func() {
 			BeforeEach(func() {

pkg/bundle/read.go

@@ -39,7 +39,7 @@ func Open(ctx context.Context, name, baseDir, file string, opts *Options) (*Bund
 	}
 
 	if file == "-" {
-		return Read(ctx, name, baseDir, os.Stdin, opts)
+		return mayCompress(ctx, name, baseDir, os.Stdin, opts)
 	}
 
 	var (
@@ -65,7 +65,7 @@ func Open(ctx context.Context, name, baseDir, file string, opts *Options) (*Bund
 		in = f
 	}
 
-	return Read(ctx, name, baseDir, in, opts)
+	return mayCompress(ctx, name, baseDir, in, opts)
 }
 
 // Try accessing the documented, primary fleet.yaml extension first. If that returns an "IsNotExist" error, then we
@@ -89,7 +89,7 @@ func setupIOReader(baseDir string) (*os.File, error) {
 	return nil, nil
 }
 
-func Read(ctx context.Context, name, baseDir string, bundleSpecReader io.Reader, opts *Options) (*Bundle, error) {
+func mayCompress(ctx context.Context, name, baseDir string, bundleSpecReader io.Reader, opts *Options) (*Bundle, error) {
 	if opts == nil {
 		opts = &Options{}
 	}

pkg/bundle/resources.go

@@ -12,6 +12,7 @@ import (
 	"net/url"
 	"os"
 	"path/filepath"
+	"regexp"
 	"sort"
 	"strings"
 	"sync"
@@ -21,6 +22,9 @@ import (
 	"github.com/pkg/errors"
 	"golang.org/x/sync/errgroup"
 	"golang.org/x/sync/semaphore"
+	"helm.sh/helm/v3/pkg/cli"
+	"helm.sh/helm/v3/pkg/downloader"
+	helmgetter "helm.sh/helm/v3/pkg/getter"
 	"helm.sh/helm/v3/pkg/repo"
 
 	"github.com/rancher/fleet/modules/cli/pkg/progress"
@@ -83,7 +87,7 @@ func readResources(ctx context.Context, spec *fleet.BundleSpec, compress bool, b
 	return result, nil
 }
 
-func ChartPath(helm *fleet.HelmOptions) string {
+func checksum(helm *fleet.HelmOptions) string {
 	if helm == nil {
 		return "none"
 	}
@@ -186,11 +190,12 @@ func addCharts(directories []directory, base string, charts []*fleet.HelmOptions
 			}
 
 			directories = append(directories, directory{
-				prefix: ChartPath(chart),
-				base:   base,
-				path:   chartURL,
-				key:    ChartPath(chart),
-				auth:   auth,
+				prefix:  checksum(chart),
+				base:    base,
+				path:    chartURL,
+				key:     checksum(chart),
+				auth:    auth,
+				version: chart.Version,
 			})
 		}
 	}
@@ -216,11 +221,12 @@ func addDirectory(directories []directory, base, customDir, defaultDir string) (
 }
 
 type directory struct {
-	prefix string
-	base   string
-	path   string
-	key    string
-	auth   Auth
+	prefix  string
+	base    string
+	path    string
+	key     string
+	version string
+	auth    Auth
 }
 
 func readDirectories(ctx context.Context, compress bool, directories ...directory) (map[string][]fleet.BundleResource, error) {
@@ -241,7 +247,7 @@ func readDirectories(ctx context.Context, compress bool, directories ...director
 		dir := dir
 		eg.Go(func() error {
 			defer sem.Release(1)
-			resources, err := readDirectory(ctx, compress, dir.prefix, dir.base, dir.path, dir.auth)
+			resources, err := readDirectory(ctx, compress, dir.prefix, dir.base, dir.path, dir.version, dir.auth)
 			if err != nil {
 				return err
 			}
@@ -261,10 +267,10 @@ func readDirectories(ctx context.Context, compress bool, directories ...director
 	return result, eg.Wait()
 }
 
-func readDirectory(ctx context.Context, compress bool, prefix, base, name string, auth Auth) ([]fleet.BundleResource, error) {
+func readDirectory(ctx context.Context, compress bool, prefix, base, name, version string, auth Auth) ([]fleet.BundleResource, error) {
 	var resources []fleet.BundleResource
 
-	files, err := readContent(ctx, base, name, auth)
+	files, err := readContent(ctx, base, name, version, auth)
 	if err != nil {
 		return nil, err
 	}
@@ -295,21 +301,36 @@ func readDirectory(ctx context.Context, compress bool, prefix, base, name string
 	return resources, nil
 }
 
-func readContent(ctx context.Context, base, name string, auth Auth) (map[string][]byte, error) {
+func readContent(ctx context.Context, base, name, version string, auth Auth) (map[string][]byte, error) {
 	temp, err := os.MkdirTemp("", "fleet")
 	if err != nil {
 		return nil, err
 	}
 	defer os.RemoveAll(temp)
 
+	src := name
+
+	// go-getter does not support downloading OCI registry based files yet
+	// until this is implemented we use Helm to download charts from OCI based registries
+	// and provide the downloaded file to go-getter locally
+	hasOCIURL, err := regexp.MatchString(`^oci:\/\/`, name)
+	if err != nil {
+		return nil, err
+	}
+	if hasOCIURL {
+		src, err = downloadOCIChart(name, version, temp)
+		if err != nil {
+			return nil, err
+		}
+	}
+
 	temp = filepath.Join(temp, "content")
 
 	base, err = filepath.Abs(base)
 	if err != nil {
 		return nil, err
 	}
 
-	src := name
 	if auth.SSHPrivateKey != nil {
 		if !strings.ContainsAny(src, "?") {
 			src += "?"
@@ -387,6 +408,21 @@ func readContent(ctx context.Context, base, name string, auth Auth) (map[string]
 	return files, nil
 }
 
+// downloadOciChart uses Helm to download charts from OCI based registries
+func downloadOCIChart(name, version, path string) (string, error) {
+	c := downloader.ChartDownloader{
+		Verify:  downloader.VerifyNever,
+		Getters: helmgetter.All(&cli.EnvSettings{}),
+	}
+
+	saved, _, err := c.DownloadTo(name, version, path)
+	if err != nil {
+		return "", err
+	}
+
+	return saved, nil
+}
+
 func newHttpGetter(auth Auth) *getter.HttpGetter {
 	httpGetter := &getter.HttpGetter{
 		Client: &http.Client{},

pkg/bundle/style.go

@@ -20,7 +20,7 @@ func chartPath(options fleet.BundleDeploymentOptions) (string, string) {
 	if options.Helm == nil || options.Helm.Chart == "" {
 		return chartYAML, ""
 	}
-	return joinAndClean(options.Helm.Chart, chartYAML), ChartPath(options.Helm) + "/"
+	return joinAndClean(options.Helm.Chart, chartYAML), checksum(options.Helm) + "/"
 }
 
 func kustomizePath(options fleet.BundleDeploymentOptions) string {