From a53f8853e3aa2e666b62607e972bbd401d3b57d6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?St=C3=A9phane=20Graber?= <stgraber@stgraber.org>
Date: Mon, 4 Nov 2024 16:07:36 -0500
Subject: [PATCH] fedora: Add support for OCI images
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Stéphane Graber <stgraber@stgraber.org>
---
 sources/fedora-http.go | 76 ++++++++++++++++++++++++++++++++++--------
 1 file changed, 62 insertions(+), 14 deletions(-)

diff --git a/sources/fedora-http.go b/sources/fedora-http.go
index 7da3e993..9eab0203 100644
--- a/sources/fedora-http.go
+++ b/sources/fedora-http.go
@@ -9,9 +9,11 @@ import (
 	"os"
 	"path/filepath"
 	"regexp"
+	"slices"
 	"sort"
 
 	"github.com/lxc/distrobuilder/shared"
+	"github.com/lxc/incus/v6/shared/subprocess"
 )
 
 type fedora struct {
@@ -20,8 +22,14 @@ type fedora struct {
 
 // Run downloads a container base image and unpacks it and its layers.
 func (s *fedora) Run() error {
-	baseURL := fmt.Sprintf("%s/packages/Fedora-Container-Base",
-		s.definition.Source.URL)
+	base := "Fedora-Container-Base-Generic"
+	extension := "oci.tar.xz"
+	if slices.Contains([]string{"39", "40"}, s.definition.Image.Release) {
+		base = "Fedora-Container-Base"
+		extension = "tar.xz"
+	}
+
+	baseURL := fmt.Sprintf("%s/packages/%s", s.definition.Source.URL, base)
 
 	// Get latest build
 	build, err := s.getLatestBuild(baseURL, s.definition.Image.Release)
@@ -29,8 +37,7 @@ func (s *fedora) Run() error {
 		return fmt.Errorf("Failed to get latest build: %w", err)
 	}
 
-	fname := fmt.Sprintf("Fedora-Container-Base-%s-%s.%s.tar.xz",
-		s.definition.Image.Release, build, s.definition.Image.ArchitectureMapped)
+	fname := fmt.Sprintf("%s-%s-%s.%s.%s", base, s.definition.Image.Release, build, s.definition.Image.ArchitectureMapped, extension)
 
 	// Download image
 	sourceURL := fmt.Sprintf("%s/%s/%s/images/%s", baseURL, s.definition.Image.Release, build, fname)
@@ -42,18 +49,59 @@ func (s *fedora) Run() error {
 
 	s.logger.WithField("file", filepath.Join(fpath, fname)).Info("Unpacking image")
 
-	// Unpack the base image
-	err = shared.Unpack(filepath.Join(fpath, fname), s.rootfsDir)
-	if err != nil {
-		return fmt.Errorf("Failed to unpack %q: %w", filepath.Join(fpath, fname), err)
-	}
+	if extension == "oci.tar.xz" {
+		// Unpack the OCI image.
+		ociDir, err := os.MkdirTemp(s.getTargetDir(), "oci.")
+		if err != nil {
+			return fmt.Errorf("Failed to create OCI path: %q: %w", ociDir, err)
+		}
 
-	s.logger.Info("Unpacking layers")
+		err = os.Mkdir(filepath.Join(ociDir, "image"), 0755)
+		if err != nil {
+			return fmt.Errorf("Failed to create OCI path: %q: %w", ociDir, err)
+		}
 
-	// Unpack the rest of the image (/bin, /sbin, /usr, etc.)
-	err = s.unpackLayers(s.rootfsDir)
-	if err != nil {
-		return fmt.Errorf("Failed to unpack: %w", err)
+		err = shared.Unpack(filepath.Join(fpath, fname), filepath.Join(ociDir, "image"))
+		if err != nil {
+			return fmt.Errorf("Failed to unpack %q: %w", filepath.Join(fpath, fname), err)
+		}
+
+		// Extract the image to a temporary path.
+		err = os.Mkdir(filepath.Join(ociDir, "content"), 0755)
+		if err != nil {
+			return fmt.Errorf("Failed to create OCI path: %q: %w", ociDir, err)
+		}
+
+		_, err = subprocess.RunCommand("umoci", "unpack", "--keep-dirlinks", "--image", fmt.Sprintf("%s:fedora:%s", filepath.Join(ociDir, "image"), s.definition.Image.Release), filepath.Join(ociDir, "content"))
+		if err != nil {
+			return fmt.Errorf("Failed to run umoci: %w", err)
+		}
+
+		// Transfer the content.
+		_, err = subprocess.RunCommand("rsync", "-avP", fmt.Sprintf("%s/rootfs/", filepath.Join(ociDir, "content")), s.rootfsDir)
+		if err != nil {
+			return fmt.Errorf("Failed to run rsync: %w", err)
+		}
+
+		// Delete the temporary directory.
+		err = os.RemoveAll(ociDir)
+		if err != nil {
+			return fmt.Errorf("Failed to wipe OCI directory: %w", err)
+		}
+	} else {
+		// Handle simple rootfs tarballs.
+		err = shared.Unpack(filepath.Join(fpath, fname), s.rootfsDir)
+		if err != nil {
+			return fmt.Errorf("Failed to unpack %q: %w", filepath.Join(fpath, fname), err)
+		}
+
+		s.logger.Info("Unpacking layers")
+
+		// Unpack the rest of the image (/bin, /sbin, /usr, etc.)
+		err = s.unpackLayers(s.rootfsDir)
+		if err != nil {
+			return fmt.Errorf("Failed to unpack: %w", err)
+		}
 	}
 
 	return nil