Move archive helpers to artifact

This allow in the future to swap and provide archive/compression methods without hijacking the code.

Refers to #33

pkg/compiler/artifact.go

@@ -16,6 +16,8 @@
 package compiler
 
 import (
+	"archive/tar"
+	"io"
 	"io/ioutil"
 	"os"
 	"path"
@@ -148,6 +150,48 @@ func (a *PackageArtifact) SetPath(p string) {
 	a.Path = p
 }
 
+// Compress Archives and compress (TODO) to the artifact path
+func (a *PackageArtifact) Compress(src string) error {
+	return helpers.Tar(src, a.Path)
+}
+
+// Unpack Untar and decompress (TODO) to the given path
+func (a *PackageArtifact) Unpack(dst string, keepPerms bool) error {
+	return helpers.Untar(a.GetPath(), dst, keepPerms)
+}
+
+func (a *PackageArtifact) FileList() ([]string, error) {
+
+	tarFile, err := os.Open(a.GetPath())
+	if err != nil {
+		return []string{}, errors.Wrap(err, "Could not open package archive")
+	}
+	defer tarFile.Close()
+	tr := tar.NewReader(tarFile)
+
+	var files []string
+	// untar each segment
+	for {
+		hdr, err := tr.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return []string{}, err
+		}
+		// determine proper file path info
+		finfo := hdr.FileInfo()
+		fileName := hdr.Name
+		if finfo.Mode().IsDir() {
+			continue
+		}
+		files = append(files, fileName)
+
+		// if a dir, create it, then go to next segment
+	}
+	return files, nil
+}
+
 type CopyJob struct {
 	Src, Dst string
 	Artifact string

pkg/compiler/compiler.go

@@ -339,13 +339,12 @@ func (cs *LuetCompiler) compileWithImage(image, buildertaggedImage, packageImage
 			// strip from includes
 			cs.stripIncludesFromRootfs(p.GetIncludes(), rootfs)
 		}
-
-		err = helpers.Tar(rootfs, p.Rel(p.GetPackage().GetFingerPrint()+".package.tar"))
+		artifact = NewPackageArtifact(p.Rel(p.GetPackage().GetFingerPrint() + ".package.tar"))
+		err = artifact.Compress(rootfs)
 		if err != nil {
 			return nil, errors.Wrap(err, "Error met while creating package archive")
 		}
 
-		artifact = NewPackageArtifact(p.Rel(p.GetPackage().GetFingerPrint() + ".package.tar"))
 		artifact.SetCompileSpec(p)
 	} else {
 		Info(pkgTag, "Generating delta")
@@ -404,8 +403,10 @@ func (cs *LuetCompiler) packageFromImage(p CompilationSpec, tag string, keepPerm
 	if err != nil {
 		return nil, errors.Wrap(err, "Could not extract rootfs")
 	}
+	artifact := NewPackageArtifact(p.Rel(p.GetPackage().GetFingerPrint() + ".package.tar"))
+	artifact.SetCompileSpec(p)
 
-	err = helpers.Tar(rootfs, p.Rel(p.GetPackage().GetFingerPrint()+".package.tar"))
+	err = artifact.Compress(rootfs)
 	if err != nil {
 		return nil, errors.Wrap(err, "Error met while creating package archive")
 	}
@@ -422,8 +423,7 @@ func (cs *LuetCompiler) packageFromImage(p CompilationSpec, tag string, keepPerm
 	}
 
 	Info(pkgTag, "   :white_check_mark: Done")
-	artifact := NewPackageArtifact(p.Rel(p.GetPackage().GetFingerPrint() + ".package.tar"))
-	artifact.SetCompileSpec(p)
+
 	err = artifact.WriteYaml(p.GetOutputPath())
 	if err != nil {
 		return artifact, err

pkg/compiler/interface.go

@@ -62,6 +62,9 @@ type Artifact interface {
 	SetCompileSpec(as CompilationSpec)
 	GetCompileSpec() CompilationSpec
 	WriteYaml(dst string) error
+	Unpack(dst string, keepPerms bool) error
+	Compress(src string) error
+	FileList() ([]string, error)
 }
 
 type ArtifactNode struct {