feat: Support legacy 'import' directive and use 'imports' for future

This changes the behavior of the 'import' target to behave as it did
before the breaking change that moved imports into /stacker/imports/

So now, if the stacker file uses 'import', then imports will
be placed in /stacker.  If the stacker file uses 'imports' (plural)
then they will be placed in /stacker/imports.

What we actually get in both cases is all the binds being done into
either /.stacker (legacy) or /stacker (new).  In the legacy case, the
imports are also bind-mounted into /stacker

Legacy (for those that used 'import:')
    stacker: /.stacker/bin/stacker
    imports: /.stacker/imports -> /stacker
    runscript: /.stacker/imports/.stacker-run.sh
    artifacts: /.stacker/artifacts

new (for those that use 'imports:')
    stacker: /stacker/bin/stacker
    imports: /stacker/imports
    runscript: /stacker/imports/.stacker-run.sh
    artifacts: /stacker/artifacts

TODO:
 * update tests
 * update docs
 * ideally get runscript into /stacker/bin

Makefile

@@ -17,7 +17,7 @@ STACKER_OPTS=--oci-dir=$(BUILD_D)/oci --roots-dir=$(BUILD_D)/roots --stacker-dir
 build_stacker = go build -tags "$(BUILD_TAGS) $1" -ldflags "-X main.version=$(VERSION_FULL) -X main.lxc_version=$(LXC_VERSION) $2" -o $3 ./cmd/stacker
 
 # See doc/hacking.md for how to use a local oci or docker repository.
-STACKER_DOCKER_BASE?=docker://
+STACKER_DOCKER_BASE ?= oci:$(CLONE_D):
 # They default to their image name in STACKER_DOCKER_BASE
 STACKER_BUILD_BASE_IMAGE?=$(STACKER_DOCKER_BASE)alpine:edge
 STACKER_BUILD_CENTOS_IMAGE?=$(STACKER_DOCKER_BASE)centos:latest
@@ -44,7 +44,7 @@ STAGE1_STACKER ?= ./stacker-dynamic
 
 STACKER_DEPS = $(GO_SRC) go.mod go.sum
 
-stacker: $(STAGE1_STACKER) $(STACKER_DEPS) cmd/stacker/lxc-wrapper/lxc-wrapper.c
+stacker: $(STAGE1_STACKER) $(STACKER_DEPS)
 	$(STAGE1_STACKER) --debug $(STACKER_OPTS) build \
 		-f build.yaml \
 		--substitute BUILD_D=$(BUILD_D) \

cmd/stacker/bom.go

@@ -10,6 +10,7 @@ import (
 	"stackerbuild.io/stacker-bom/pkg/bom"
 	"stackerbuild.io/stacker-bom/pkg/distro"
 	"stackerbuild.io/stacker-bom/pkg/fs"
+	"stackerbuild.io/stacker/pkg/types"
 )
 
 var bomCmd = cli.Command{
@@ -39,7 +40,7 @@ func doBomDiscover(ctx *cli.Context) error {
 	author := "stacker-internal"
 	org := "stacker-internal"
 
-	if err := fs.Discover(author, org, "/stacker/artifacts/installed-packages.json"); err != nil {
+	if err := fs.Discover(author, org, types.InternalStackerDir+"/artifacts/installed-packages.json"); err != nil {
 		return nil
 	}
 
@@ -57,7 +58,8 @@ func doBomGenerate(ctx *cli.Context) error {
 	org := "stacker-internal"
 	lic := "unknown"
 
-	if err := distro.ParsePackage(input, author, org, lic, fmt.Sprintf("/stacker/artifacts/%s.json", filepath.Base(input))); err != nil {
+	if err := distro.ParsePackage(input, author, org, lic, fmt.Sprintf("%s/artifacts/%s.json",
+		types.InternalStackerDir, filepath.Base(input))); err != nil {
 		return nil
 	}
 
@@ -98,16 +100,17 @@ func doBomVerify(ctx *cli.Context) error {
 	org := ctx.Args().Get(3)
 
 	// first merge all individual sbom artifacts that may have been generated
-	if err := bom.MergeDocuments("/stacker/artifacts", name, author, org, dest); err != nil {
+	iDir := types.InternalStackerDir
+	if err := bom.MergeDocuments(iDir+"/artifacts", name, author, org, dest); err != nil {
 		return err
 	}
 
 	// check against inventory
 	if err := fs.GenerateInventory("/",
-		[]string{"/proc", "/sys", "/dev", "/etc/resolv.conf", "/stacker"},
-		"/stacker/artifacts/inventory.json"); err != nil {
+		[]string{"/proc", "/sys", "/dev", "/etc/resolv.conf", iDir},
+		iDir+"/artifacts/inventory.json"); err != nil {
 		return err
 	}
 
-	return fs.Verify(dest, "/stacker/artifacts/inventory.json", "")
+	return fs.Verify(dest, iDir+"/artifacts/inventory.json", "")
 }

cmd/stacker/chroot.go

@@ -98,11 +98,11 @@ func doChroot(ctx *cli.Context) error {
 	}
 	defer c.Close()
 
-	err = stacker.SetupBuildContainerConfig(config, s, c, name)
+	err = stacker.SetupBuildContainerConfig(config, s, c, types.InternalStackerDir, name)
 	if err != nil {
 		return err
 	}
-	err = stacker.SetupLayerConfig(config, c, layer, name)
+	err = stacker.SetupLayerConfig(config, c, layer, types.InternalStackerDir, name)
 	if err != nil {
 		return err
 	}

pkg/stacker/bom.go

@@ -5,6 +5,7 @@ import (
 	"io"
 	"os"
 	"path"
+	"path/filepath"
 
 	"stackerbuild.io/stacker/pkg/container"
 	"stackerbuild.io/stacker/pkg/log"
@@ -27,24 +28,25 @@ func BuildLayerArtifacts(sc types.StackerConfig, storage types.Storage, l types.
 	}
 	defer c.Close()
 
-	err = SetupBuildContainerConfig(sc, storage, c, tag)
+	inDir := types.InternalStackerDir
+	err = SetupBuildContainerConfig(sc, storage, c, inDir, tag)
 	if err != nil {
 		log.Errorf("build container %v", err)
 		return err
 	}
 
-	err = SetupLayerConfig(sc, c, l, tag)
+	err = SetupLayerConfig(sc, c, l, inDir, tag)
 	if err != nil {
 		return err
 	}
 
-	cmd := []string{insideStaticStacker}
+	cmd := []string{filepath.Join(inDir, types.BinStacker)}
 
 	if sc.Debug {
 		cmd = append(cmd, "--debug")
 	}
 
-	cmd = append(cmd, "bom", "build", "/stacker/artifacts",
+	cmd = append(cmd, "bom", "build", filepath.Join(inDir, "artifacts"),
 		l.Annotations[types.AuthorAnnotation],
 		l.Annotations[types.OrgAnnotation],
 		l.Annotations[types.LicenseAnnotation],
@@ -71,25 +73,26 @@ func VerifyLayerArtifacts(sc types.StackerConfig, storage types.Storage, l types
 	}
 	defer c.Close()
 
-	err = SetupBuildContainerConfig(sc, storage, c, tag)
+	inDir := types.InternalStackerDir
+	err = SetupBuildContainerConfig(sc, storage, c, inDir, tag)
 	if err != nil {
 		log.Errorf("build container %v", err)
 		return err
 	}
 
-	err = SetupLayerConfig(sc, c, l, tag)
+	err = SetupLayerConfig(sc, c, l, inDir, tag)
 	if err != nil {
 		return err
 	}
 
-	cmd := []string{insideStaticStacker}
+	cmd := []string{filepath.Join(inDir, types.BinStacker)}
 
 	if sc.Debug {
 		cmd = append(cmd, "--debug")
 	}
 
 	cmd = append(cmd, "bom", "verify",
-		fmt.Sprintf("/stacker/artifacts/%s.json", tag),
+		fmt.Sprintf(types.InternalStackerDir+"/artifacts/%s.json", tag),
 		tag, l.Annotations[types.AuthorAnnotation], l.Annotations[types.OrgAnnotation])
 
 	err = c.Execute(cmd, os.Stdin)

pkg/stacker/build.go

@@ -7,6 +7,7 @@ import (
 	"os/exec"
 	"os/user"
 	"path"
+	"path/filepath"
 	"strings"
 	"time"
 
@@ -22,8 +23,7 @@ import (
 )
 
 const (
-	DefaultShell        = "/bin/sh"
-	insideStaticStacker = "/stacker/tools/static-stacker"
+	DefaultShell = "/bin/sh"
 )
 
 type BuildArgs struct {
@@ -114,6 +114,11 @@ func (b *Builder) updateOCIConfigForOutput(sf *types.Stackerfile, s types.Storag
 		imageConfig.Labels = map[string]string{}
 	}
 
+	inDir := types.InternalStackerDir
+	if l.WasLegacyImport {
+		inDir = types.LegacyInternalStackerDir
+	}
+
 	if len(l.GenerateLabels) > 0 {
 		writable, cleanup, err := s.TemporaryWritableSnapshot(name)
 		if err != nil {
@@ -133,24 +138,26 @@ func (b *Builder) updateOCIConfigForOutput(sf *types.Stackerfile, s types.Storag
 		}
 		defer c.Close()
 
-		err = SetupBuildContainerConfig(opts.Config, s, c, writable)
+		err = SetupBuildContainerConfig(opts.Config, s, c, inDir, writable)
 		if err != nil {
 			return err
 		}
 
-		err = c.BindMount(dir, "/stacker/oci-labels", "")
+		// /stacker/oci-labels
+		labelInDir := filepath.Join(inDir, "oci-labels")
+		const script = ".stacker-run.sh"
+		err = c.BindMount(dir, labelInDir, "")
 		if err != nil {
 			return err
 		}
 
-		rootfs := path.Join(opts.Config.RootFSDir, writable, "rootfs")
-		runPath := path.Join(dir, ".stacker-run.sh")
-		err = generateShellForRunning(rootfs, l.GenerateLabels, runPath)
+		rootfs := filepath.Join(opts.Config.RootFSDir, writable, "rootfs")
+		err = generateShellForRunning(rootfs, l.GenerateLabels, filepath.Join(dir, script))
 		if err != nil {
 			return err
 		}
 
-		err = c.Execute([]string{"/stacker/oci-labels/.stacker-run.sh"}, nil)
+		err = c.Execute([]string{filepath.Join(labelInDir, script)}, nil)
 		if err != nil {
 			return err
 		}
@@ -165,7 +172,7 @@ func (b *Builder) updateOCIConfigForOutput(sf *types.Stackerfile, s types.Storag
 				continue
 			}
 
-			content, err := os.ReadFile(path.Join(dir, ent.Name()))
+			content, err := os.ReadFile(filepath.Join(dir, ent.Name()))
 			if err != nil {
 				return errors.Wrapf(err, "couldn't read label %s", ent.Name())
 			}
@@ -361,6 +368,10 @@ func (b *Builder) build(s types.Storage, file string) error {
 		}
 
 		log.Infof("preparing image %s...", name)
+		inDir := types.InternalStackerDir
+		if l.WasLegacyImport {
+			inDir = types.LegacyInternalStackerDir
+		}
 
 		// We need to run the imports first since we now compare
 		// against imports for caching layers. Since we don't do
@@ -450,18 +461,18 @@ func (b *Builder) build(s types.Storage, file string) error {
 		}
 		defer c.Close()
 
-		err = SetupBuildContainerConfig(opts.Config, s, c, name)
+		err = SetupBuildContainerConfig(opts.Config, s, c, inDir, name)
 		if err != nil {
 			return err
 		}
 
-		err = SetupLayerConfig(opts.Config, c, l, name)
+		err = SetupLayerConfig(opts.Config, c, l, inDir, name)
 		if err != nil {
 			return err
 		}
 
 		if opts.SetupOnly {
-			err = c.SaveConfigFile(path.Join(opts.Config.RootFSDir, name, "lxc.conf"))
+			err = c.SaveConfigFile(filepath.Join(opts.Config.RootFSDir, name, "lxc.conf"))
 			if err != nil {
 				return errors.Wrapf(err, "error saving config file for %s", name)
 			}
@@ -471,15 +482,15 @@ func (b *Builder) build(s types.Storage, file string) error {
 		}
 
 		if len(l.Run) != 0 {
-			rootfs := path.Join(opts.Config.RootFSDir, name, "rootfs")
-			shellScript := path.Join(opts.Config.StackerDir, "imports", name, ".stacker-run.sh")
+			rootfs := filepath.Join(opts.Config.RootFSDir, name, "rootfs")
+			shellScript := filepath.Join(opts.Config.StackerDir, "imports", name, ".stacker-run.sh")
 			err = generateShellForRunning(rootfs, l.Run, shellScript)
 			if err != nil {
 				return err
 			}
 
 			// These should all be non-interactive; let's ensure that.
-			err = c.Execute([]string{"/stacker/imports/.stacker-run.sh"}, nil)
+			err = c.Execute([]string{filepath.Join(inDir, "imports", ".stacker-run.sh")}, nil)
 			if err != nil {
 				if opts.OnRunFailure != "" {
 					err2 := c.Execute([]string{opts.OnRunFailure}, os.Stdin)
@@ -654,7 +665,7 @@ func runInternalGoSubcommand(config types.StackerConfig, args []string) error {
 	return errors.WithStack(c.Run())
 }
 
-func SetupBuildContainerConfig(config types.StackerConfig, storage types.Storage, c *container.Container, name string) error {
+func SetupBuildContainerConfig(config types.StackerConfig, storage types.Storage, c *container.Container, inDir string, name string) error {
 	rootfsPivot := path.Join(config.StackerDir, "rootfsPivot")
 	if err := os.MkdirAll(rootfsPivot, 0755); err != nil {
 		return err
@@ -695,7 +706,7 @@ func SetupBuildContainerConfig(config types.StackerConfig, storage types.Storage
 	}
 
 	// make stacker binary available inside container
-	if err := c.BindMount(binary, insideStaticStacker, ""); err != nil {
+	if err := c.BindMount(binary, filepath.Join(inDir, "bin/stacker"), ""); err != nil {
 		return err
 	}
 
@@ -732,19 +743,27 @@ func SetupBuildContainerConfig(config types.StackerConfig, storage types.Storage
 	return nil
 }
 
-func SetupLayerConfig(config types.StackerConfig, c *container.Container, l types.Layer, name string) error {
+func SetupLayerConfig(config types.StackerConfig, c *container.Container, l types.Layer, inDir, name string) error {
 	env, err := l.BuildEnvironment(name)
 	if err != nil {
 		return err
 	}
 
 	importsDir := path.Join(config.StackerDir, "imports", name)
 	if _, err := os.Stat(importsDir); err == nil {
-		log.Debugf("bind mounting %s into container", importsDir)
-		err = c.BindMount(importsDir, "/stacker/imports", "ro")
+		d := filepath.Join(inDir, "imports")
+		log.Debugf("bind mounting %s into container at %s", importsDir, d)
+		err = c.BindMount(importsDir, d, "ro")
 		if err != nil {
 			return err
 		}
+		// legacy expect imports in /stacker
+		if inDir == types.LegacyInternalStackerDir {
+			err = c.BindMount(importsDir, types.InternalStackerDir, "ro")
+			if err != nil {
+				return err
+			}
+		}
 	} else {
 		log.Debugf("not bind mounting %s into container", importsDir)
 	}
@@ -753,8 +772,9 @@ func SetupLayerConfig(config types.StackerConfig, c *container.Container, l type
 	if l.Bom != nil {
 		artifactsDir := path.Join(config.StackerDir, "artifacts", name)
 		if _, err := os.Stat(artifactsDir); err == nil {
-			log.Debugf("bind mounting %s into container", artifactsDir)
-			err = c.BindMount(artifactsDir, "/stacker/artifacts", "rw")
+			d := filepath.Join(inDir, "artifacts")
+			log.Debugf("bind mounting %s dir into container at %s", artifactsDir, d)
+			err = c.BindMount(artifactsDir, d, "rw")
 			if err != nil {
 				return err
 			}

pkg/stacker/grab.go

@@ -5,6 +5,7 @@ import (
 	"io/fs"
 	"os"
 	"path"
+	"path/filepath"
 
 	"stackerbuild.io/stacker/pkg/container"
 	"stackerbuild.io/stacker/pkg/types"
@@ -19,30 +20,31 @@ func Grab(sc types.StackerConfig, storage types.Storage, name string, source str
 	}
 	defer c.Close()
 
-	err = c.BindMount(targetDir, "/stacker", "")
+	err = c.BindMount(targetDir, types.InternalStackerDir, "")
 	if err != nil {
 		return err
 	}
 	defer os.Remove(path.Join(sc.RootFSDir, name, "rootfs", "stacker"))
 
-	err = SetupBuildContainerConfig(sc, storage, c, name)
+	err = SetupBuildContainerConfig(sc, storage, c, types.InternalStackerDir, name)
 	if err != nil {
 		return err
 	}
 
-	bcmd := []string{insideStaticStacker, "internal-go"}
+	bcmd := []string{filepath.Join(types.InternalStackerDir, types.BinStacker), "internal-go"}
 
+	iDestName := filepath.Join(types.InternalStackerDir, path.Base(source))
 	if idest == "" || source[len(source)-1:] != "/" {
-		err = c.Execute(append(bcmd, "cp", source, "/stacker/"+path.Base(source)), nil)
+		err = c.Execute(append(bcmd, "cp", source, iDestName), nil)
 	} else {
-		err = c.Execute(append(bcmd, "cp", source, "/stacker/"), nil)
+		err = c.Execute(append(bcmd, "cp", source, types.InternalStackerDir+"/"), nil)
 	}
 	if err != nil {
 		return err
 	}
 
 	if mode != nil {
-		err = c.Execute(append(bcmd, "chmod", fmt.Sprintf("%o", *mode), "/stacker/"+path.Base(source)), nil)
+		err = c.Execute(append(bcmd, "chmod", fmt.Sprintf("%o", *mode), iDestName), nil)
 		if err != nil {
 			return err
 		}
@@ -54,7 +56,7 @@ func Grab(sc types.StackerConfig, storage types.Storage, name string, source str
 			owns += fmt.Sprintf(":%d", gid)
 		}
 
-		err = c.Execute(append(bcmd, "chown", owns, "/stacker/"+path.Base(source)), nil)
+		err = c.Execute(append(bcmd, "chown", owns, iDestName), nil)
 		if err != nil {
 			return err
 		}