refactor: Bind stacker binary into container in SetupBuildContainerCo…

…nfig

Previously there were 3 individual calls to bind stacker into
tools/static-stacker.  This just changes that to 1 place, so
after calling SetupBuildContainerConfig you can use stacker inside.

Signed-off-by: Scott Moser <smoser@brickies.net>

pkg/stacker/bom.go

@@ -38,16 +38,7 @@ func BuildLayerArtifacts(sc types.StackerConfig, storage types.Storage, l types.
 		return err
 	}
 
-	binary, err := os.Readlink("/proc/self/exe")
-	if err != nil {
-		return err
-	}
-
-	if err := c.BindMount(binary, "/stacker/tools/static-stacker", ""); err != nil {
-		return err
-	}
-
-	cmd := []string{"/stacker/tools/static-stacker"}
+	cmd := []string{insideStaticStacker}
 
 	if sc.Debug {
 		cmd = append(cmd, "--debug")
@@ -92,16 +83,7 @@ func VerifyLayerArtifacts(sc types.StackerConfig, storage types.Storage, l types
 		return err
 	}
 
-	binary, err := os.Readlink("/proc/self/exe")
-	if err != nil {
-		return err
-	}
-
-	if err := c.BindMount(binary, "/stacker/tools/static-stacker", ""); err != nil {
-		return err
-	}
-
-	cmd := []string{"/stacker/tools/static-stacker"}
+	cmd := []string{insideStaticStacker}
 
 	if sc.Debug {
 		cmd = append(cmd, "--debug")

pkg/stacker/build.go

@@ -21,7 +21,10 @@ import (
 	"stackerbuild.io/stacker/pkg/types"
 )
 
-const DefaultShell = "/bin/sh"
+const (
+	DefaultShell        = "/bin/sh"
+	insideStaticStacker = "/stacker/tools/static-stacker"
+)
 
 type BuildArgs struct {
 	Config               types.StackerConfig
@@ -687,6 +690,16 @@ func SetupBuildContainerConfig(config types.StackerConfig, storage types.Storage
 		return err
 	}
 
+	binary, err := os.Readlink("/proc/self/exe")
+	if err != nil {
+		return err
+	}
+
+	// make stacker binary available inside container
+	if err := c.BindMount(binary, insideStaticStacker, ""); err != nil {
+		return err
+	}
+
 	rootfs, err := storage.GetLXCRootfsConfig(name)
 	if err != nil {
 		return err
@@ -749,19 +762,6 @@ func SetupLayerConfig(config types.StackerConfig, c *container.Container, l type
 		} else {
 			log.Debugf("not bind mounting %s into container", artifactsDir)
 		}
-
-		// make stacker also available to run the internal bom cmds
-		binary, err := os.Readlink("/proc/self/exe")
-		if err != nil {
-			return errors.Wrapf(err, "couldn't find executable for bind mount")
-		}
-
-		err = c.BindMount(binary, "/stacker/tools/static-stacker", "")
-		if err != nil {
-			return err
-		}
-
-		log.Debugf("bind mounting %s into container", binary)
 	}
 
 	for k, v := range env {

pkg/stacker/grab.go

@@ -6,7 +6,6 @@ import (
 	"os"
 	"path"
 
-	"github.com/pkg/errors"
 	"stackerbuild.io/stacker/pkg/container"
 	"stackerbuild.io/stacker/pkg/types"
 )
@@ -26,22 +25,12 @@ func Grab(sc types.StackerConfig, storage types.Storage, name string, source str
 	}
 	defer os.Remove(path.Join(sc.RootFSDir, name, "rootfs", "stacker"))
 
-	binary, err := os.Readlink("/proc/self/exe")
-	if err != nil {
-		return errors.Wrapf(err, "couldn't find executable for bind mount")
-	}
-
-	err = c.BindMount(binary, "/stacker/tools/static-stacker", "")
-	if err != nil {
-		return err
-	}
-
 	err = SetupBuildContainerConfig(sc, storage, c, name)
 	if err != nil {
 		return err
 	}
 
-	bcmd := []string{"/stacker/tools/static-stacker", "internal-go"}
+	bcmd := []string{insideStaticStacker, "internal-go"}
 	err = c.Execute(append(bcmd, "cp", source, "/stacker/"+path.Base(source)), nil)
 	if err != nil {
 		return err