From 72652c0f44ba1e471e3491c62162613b433bbe71 Mon Sep 17 00:00:00 2001
From: Luis Davim <luis.davim@sendoso.com>
Date: Fri, 17 Sep 2021 09:26:43 +0100
Subject: [PATCH] feat: support the new OCI implementation from helm 3.7.0

Signed-off-by: Luis Davim <luis.davim@sendoso.com>
---
 internal/app/helm_helpers.go | 11 ++++++++++
 internal/app/utils.go        | 40 ++++++++++++++++++++++++++++++++----
 internal/app/utils_test.go   | 40 ++++++++++++++++++++++++++++++++++++
 3 files changed, 87 insertions(+), 4 deletions(-)

diff --git a/internal/app/helm_helpers.go b/internal/app/helm_helpers.go
index 598f906d..43af55b2 100644
--- a/internal/app/helm_helpers.go
+++ b/internal/app/helm_helpers.go
@@ -111,6 +111,7 @@ func updateChartDep(chartPath string) error {
 }
 
 // helmExportChart pulls chart and exports it to the specified destination
+// this is only compatible with hlem versions lower than 3.0.7
 func helmExportChart(chart, dest string) error {
 	cmd := helmCmd([]string{"chart", "pull", chart}, "Pulling chart [ "+chart+" ] to local registry cache")
 	if _, err := cmd.Exec(); err != nil {
@@ -123,6 +124,16 @@ func helmExportChart(chart, dest string) error {
 	return nil
 }
 
+// helmPullChart pulls chart and exports it to the specified destination
+// this should only be used with helm versions greater or equal to 3.7.0
+func helmPullChart(chart, dest string) error {
+	cmd := helmCmd([]string{"chart", "pull", chart, "-d", dest}, "Pulling chart [ "+chart+" ] to "+dest)
+	if _, err := cmd.Exec(); err != nil {
+		return err
+	}
+	return nil
+}
+
 // addHelmRepos adds repositories to Helm if they don't exist already.
 // Helm does not mind if a repo with the same name exists. It treats it as an update.
 func addHelmRepos(repos map[string]string) error {
diff --git a/internal/app/utils.go b/internal/app/utils.go
index 78cc3df9..da5ce729 100644
--- a/internal/app/utils.go
+++ b/internal/app/utils.go
@@ -15,6 +15,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/Masterminds/semver"
 	"github.com/Praqma/helmsman/internal/aws"
@@ -198,6 +199,25 @@ func sliceContains(slice []string, s string) bool {
 	return false
 }
 
+// replaceAtIndex replaces the charecter at the given index in the string with the given rune
+func replaceAtIndex(in string, r rune, i int) (string, error) {
+	if i < 0 || i >= utf8.RuneCountInString(in) {
+		return in, fmt.Errorf("index out of bounds")
+	}
+	out := []rune(in)
+	out[i] = r
+	return string(out), nil
+}
+
+// ociRefToFilename computes the helm package filename for a given OCI ref
+func ociRefToFilename(ref string) (string, error) {
+	var err error
+	fileName := filepath.Base(ref)
+	i := strings.LastIndex(fileName, ":")
+	fileName, err = replaceAtIndex(fileName, '-', i)
+	return fmt.Sprintf("%s.tgz", fileName), err
+}
+
 // downloadFile downloads a file from a URL, GCS, Azure or AWS buckets and saves it with a
 // given outfile name and in a given dir
 // If the file path is local file system path, it returns the absolute path to the file
@@ -210,11 +230,23 @@ func downloadFile(file string, dir string, outfile string) string {
 	switch u.Scheme {
 	case "oci":
 		dest := filepath.Dir(outfile)
-		fileName := strings.Split(filepath.Base(file), ":")[0]
-		if err := helmExportChart(strings.ReplaceAll(file, "oci://", ""), dest); err != nil {
-			log.Fatal(err.Error())
+		switch {
+		case checkHelmVersion("<3.7.0"):
+			fileName := strings.Split(filepath.Base(file), ":")[0]
+			if err := helmExportChart(strings.ReplaceAll(file, "oci://", ""), dest); err != nil {
+				log.Fatal(err.Error())
+			}
+			return filepath.Join(dest, fileName)
+		default:
+			fileName, err := ociRefToFilename(file)
+			if err != nil {
+				log.Fatal(err.Error())
+			}
+			if err := helmPullChart(file, dest); err != nil {
+				log.Fatal(err.Error())
+			}
+			return filepath.Join(dest, fileName)
 		}
-		return filepath.Join(dest, fileName)
 	case "https", "http":
 		if err := downloadFileFromURL(file, outfile); err != nil {
 			log.Fatal(err.Error())
diff --git a/internal/app/utils_test.go b/internal/app/utils_test.go
index ae079c70..1e282016 100644
--- a/internal/app/utils_test.go
+++ b/internal/app/utils_test.go
@@ -5,6 +5,46 @@ import (
 	"testing"
 )
 
+func TestOciRefToFilename(t *testing.T) {
+	tests := []struct {
+		name string
+		in   string
+		want string
+	}{
+		{
+			name: "no_repo",
+			in:   "my-chart:1.2.3",
+			want: "my-chart-1.2.3.tgz",
+		},
+		{
+			name: "two_colons",
+			in:   "my:chart:1.2.3",
+			want: "my:chart-1.2.3.tgz",
+		},
+		{
+			name: "with_Host",
+			in:   "my-repo.example.com/charts/my-chart:1.2.3",
+			want: "my-chart-1.2.3.tgz",
+		},
+		{
+			name: "full_url",
+			in:   "oci://my-repo.example.com/charts/my-chart:1.2.3",
+			want: "my-chart-1.2.3.tgz",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := ociRefToFilename(tt.in)
+			if err != nil {
+				t.Errorf("ociRefToFilename() unexpected error: %v", err)
+			}
+			if got != tt.want {
+				t.Errorf("ociRefToFilename() got = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
 func Test_isOfType(t *testing.T) {
 	type args struct {
 		filename  string