Add convert command using bib

Add convert command that uses bootc image builder (bib)
to create disk images

Signed-off-by: German Maglione <[email protected]>

Author: germag

cmd/convert.go

@@ -0,0 +1,67 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/containers/podman-bootc/pkg/bib"
+	"github.com/containers/podman-bootc/pkg/user"
+	"github.com/containers/podman-bootc/pkg/utils"
+
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+var (
+	convertCmd = &cobra.Command{
+		Use:   "convert <image>",
+		Short: "Creates a disk image using bootc-image-builder",
+		Long:  "Creates a disk image using bootc-image-builder",
+		Args:  cobra.ExactArgs(1),
+		RunE:  doConvert,
+	}
+	options bib.BuildOption
+	quiet   bool
+)
+
+func init() {
+	RootCmd.AddCommand(convertCmd)
+	convertCmd.Flags().BoolVar(&quiet, "quiet", false, "Suppress output from disk image creation")
+	convertCmd.Flags().StringVar(&options.Config, "config", "", "Image builder config file")
+	convertCmd.Flags().StringVar(&options.Output, "output", ".", "output directory (default \".\")")
+	// Corresponds to bib '--rootfs', we don't use 'rootfs' so to not be confused with podman's 'rootfs' options
+	// Note: we cannot provide a default value for the filesystem, since this options will overwrite the one defined in
+	// the image
+	convertCmd.Flags().StringVar(&options.Filesystem, "filesystem", "", "Overrides the root filesystem (e.g. xfs, btrfs, ext4)")
+	// Corresponds to bib '--type', using '--format' to be consistent with podman
+	convertCmd.Flags().StringVar(&options.Format, "format", "qcow2", "Disk image type (ami, anaconda-iso, iso, qcow2, raw, vmdk) [default: qcow2]")
+	// Corresponds to bib '--target-arch', using '--arch' to be consistent with podman
+	convertCmd.Flags().StringVar(&options.Arch, "arch", "", "Build for the given target architecture (experimental)")
+
+	options.BibContainerImage = os.Getenv("PODMAN_BOOTC_BIB_IMAGE")
+	options.BibExtraArgs = strings.Fields(os.Getenv("PODMAN_BOOTC_BIB_EXTRA"))
+}
+
+func doConvert(_ *cobra.Command, args []string) (err error) {
+	//get user info who is running the podman bootc command
+	user, err := user.NewUser()
+	if err != nil {
+		return fmt.Errorf("unable to get user: %w", err)
+	}
+
+	machine, err := utils.GetMachineContext()
+	if err != nil {
+		println(utils.PodmanMachineErrorMessage)
+		logrus.Errorf("failed to connect to podman machine. Is podman machine running?\n%s", err)
+		return err
+	}
+
+	idOrName := args[0]
+	err = bib.Build(machine.Ctx, user, idOrName, quiet, options)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

pkg/bib/build.go

@@ -0,0 +1,230 @@
+package bib
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/containers/podman-bootc/pkg/user"
+	"github.com/containers/podman-bootc/pkg/utils"
+
+	"github.com/containers/podman/v5/pkg/bindings/containers"
+	"github.com/containers/podman/v5/pkg/bindings/images"
+	"github.com/containers/podman/v5/pkg/domain/entities/types"
+	"github.com/containers/podman/v5/pkg/specgen"
+	"github.com/opencontainers/runtime-spec/specs-go"
+	"github.com/sirupsen/logrus"
+)
+
+const defaultBibImage = "quay.io/centos-bootc/bootc-image-builder"
+
+type BuildOption struct {
+	BibContainerImage string
+	Config            string
+	Output            string
+	Filesystem        string
+	Format            string
+	Arch              string
+	BibExtraArgs      []string
+}
+
+func Build(ctx context.Context, user user.User, imageNameOrId string, quiet bool, buildOption BuildOption) error {
+	outputInfo, err := os.Stat(buildOption.Output)
+	if err != nil {
+		return fmt.Errorf("output directory %s: %w", buildOption.Output, err)
+	}
+
+	if !outputInfo.IsDir() {
+		return fmt.Errorf("%s is not a directory ", buildOption.Output)
+	}
+
+	_, err = os.Stat(buildOption.Config)
+	if err != nil {
+		return fmt.Errorf("config file %s: %w", buildOption.Config, err)
+	}
+
+	// Let's convert both the config file and the output directory to their absolute paths.
+	buildOption.Output, err = filepath.Abs(buildOption.Output)
+	if err != nil {
+		return fmt.Errorf("getting output directory absolute path: %w", err)
+	}
+
+	buildOption.Config, err = filepath.Abs(buildOption.Config)
+	if err != nil {
+		return fmt.Errorf("getting config file absolute path: %w", err)
+	}
+
+	// We assume the user's home directory is accessible from the podman machine VM, this
+	// will fail if any of the output or the config file are outside the user's home directory.
+	if !strings.HasPrefix(buildOption.Output, user.HomeDir()) {
+		return errors.New("the output directory must be inside the user's home directory")
+	}
+
+	if !strings.HasPrefix(buildOption.Config, user.HomeDir()) {
+		return errors.New("the output directory must be inside the user's home directory")
+	}
+
+	// Let's pull the bootc image container if necessary
+	imageInspect, err := utils.PullAndInspect(ctx, imageNameOrId)
+	if err != nil {
+		return fmt.Errorf("pulling image: %w", err)
+	}
+	imageFullName := imageInspect.RepoTags[0]
+
+	if buildOption.BibContainerImage == "" {
+		label, found := imageInspect.Labels["bootc.diskimage-builder"]
+		if found && label != "" {
+			buildOption.BibContainerImage = label
+		} else {
+			buildOption.BibContainerImage = defaultBibImage
+		}
+	}
+
+	// Let's pull the Bootc Image Builder if necessary
+	_, err = utils.PullAndInspect(ctx, buildOption.BibContainerImage)
+	if err != nil {
+		return fmt.Errorf("pulling bootc image builder image: %w", err)
+	}
+
+	// BIB doesn't work with just the image ID or short name, it requires the image full name
+	bibContainer, err := createBibContainer(ctx, buildOption.BibContainerImage, imageFullName, buildOption)
+	if err != nil {
+		return fmt.Errorf("failed to create image builder container: %w", err)
+	}
+
+	err = containers.Start(ctx, bibContainer.ID, &containers.StartOptions{})
+	if err != nil {
+		return fmt.Errorf("failed to start image builder container: %w", err)
+	}
+
+	// Ensure we've cancelled the container attachment when exiting this function, as
+	// it takes over stdout/stderr handling
+	attachCancelCtx, cancelAttach := context.WithCancel(ctx)
+	defer cancelAttach()
+
+	if !quiet {
+		attachOpts := new(containers.AttachOptions).WithStream(true)
+		if err := containers.Attach(attachCancelCtx, bibContainer.ID, os.Stdin, os.Stdout, os.Stderr, nil, attachOpts); err != nil {
+			return fmt.Errorf("attaching image builder container: %w", err)
+		}
+	}
+
+	exitCode, err := containers.Wait(ctx, bibContainer.ID, nil)
+	if err != nil {
+		return fmt.Errorf("failed to wait for image builder container: %w", err)
+	}
+
+	if exitCode != 0 {
+		return fmt.Errorf("failed to run image builder")
+	}
+
+	return nil
+}
+
+// pullImage fetches the container image if not present
+func pullImage(ctx context.Context, imageNameOrId string) (imageFullName string, err error) {
+	pullPolicy := "missing"
+	ids, err := images.Pull(ctx, imageNameOrId, &images.PullOptions{Policy: &pullPolicy})
+	if err != nil {
+		return "", fmt.Errorf("failed to pull image: %w", err)
+	}
+
+	if len(ids) == 0 {
+		return "", fmt.Errorf("no ids returned from image pull")
+	}
+
+	if len(ids) > 1 {
+		return "", fmt.Errorf("multiple ids returned from image pull")
+	}
+
+	imageInfo, err := images.GetImage(ctx, imageNameOrId, &images.GetOptions{})
+	if err != nil {
+		return "", fmt.Errorf("failed to get image: %w", err)
+	}
+
+	return imageInfo.RepoTags[0], nil
+}
+
+func createBibContainer(ctx context.Context, bibContainerImage, imageFullName string, buildOption BuildOption) (types.ContainerCreateResponse, error) {
+	privileged := true
+	autoRemove := true
+	labelNested := true
+	terminal := true // Allocate pty so we can show progress bars, spinners etc.
+
+	bibArgs := bibArguments(imageFullName, buildOption)
+
+	s := &specgen.SpecGenerator{
+		ContainerBasicConfig: specgen.ContainerBasicConfig{
+			Remove:       &autoRemove,
+			Annotations:  map[string]string{"io.podman.annotations.label": "type:unconfined_t"},
+			Terminal:     &terminal,
+			Command:      bibArgs,
+			SdNotifyMode: "container", // required otherwise crun will fail to open the sd-bus
+		},
+		ContainerStorageConfig: specgen.ContainerStorageConfig{
+			Image: bibContainerImage,
+			Mounts: []specs.Mount{
+				{
+					Source:      buildOption.Config,
+					Destination: "/config.toml",
+					Type:        "bind",
+				},
+				{
+					Source:      buildOption.Output,
+					Destination: "/output",
+					Type:        "bind",
+					Options:     []string{"nosuid", "nodev"},
+				},
+				{
+					Source:      "/var/lib/containers/storage",
+					Destination: "/var/lib/containers/storage",
+					Type:        "bind",
+				},
+			},
+		},
+		ContainerSecurityConfig: specgen.ContainerSecurityConfig{
+			Privileged:  &privileged,
+			LabelNested: &labelNested,
+			SelinuxOpts: []string{"type:unconfined_t"},
+		},
+		ContainerNetworkConfig: specgen.ContainerNetworkConfig{
+			NetNS: specgen.Namespace{
+				NSMode: specgen.Bridge,
+			},
+		},
+	}
+
+	logrus.Debugf("Installing %s using %s", imageFullName, bibContainerImage)
+	createResponse, err := containers.CreateWithSpec(ctx, s, &containers.CreateOptions{})
+	if err != nil {
+		return createResponse, fmt.Errorf("failed to create image builder container: %w", err)
+	}
+	return createResponse, nil
+}
+
+func bibArguments(imageNameOrId string, buildOption BuildOption) []string {
+	args := []string{
+		"--local", // we pull the image if necessary, so don't pull it from a registry
+	}
+
+	if buildOption.Filesystem != "" {
+		args = append(args, "--rootfs", buildOption.Filesystem)
+	}
+
+	if buildOption.Arch != "" {
+		args = append(args, "--target-arch", buildOption.Arch)
+	}
+
+	if buildOption.Format != "" {
+		args = append(args, "--type", buildOption.Format)
+	}
+
+	args = append(args, buildOption.BibExtraArgs...)
+	args = append(args, imageNameOrId)
+
+	logrus.Debugf("BIB arguments: %v", args)
+	return args
+}