// BuildSnapfsSnap the given sourceDirectory and return the generated snap file
func BuildSnapfsSnap(sourceDir, targetDir string) (string, error) {
// create build dir
buildDir, err := ioutil.TempDir("", "snappy-build-")
if err != nil {
return "", err
}
defer os.RemoveAll(buildDir)
snapName, err := prepare(sourceDir, targetDir, buildDir)
if err != nil {
return "", err
}
d := snapfs.New(snapName)
if err = d.Build(buildDir); err != nil {
return "", err
}
return snapName, nil
}
// OpenPackageFile opens a given snap file with the right backend
func OpenPackageFile(path string) (PackageFile, error) {
f, err := os.Open(path)
if err != nil {
return nil, err
}
defer f.Close()
// look, libmagic!
header := make([]byte, 20)
if _, err := f.Read(header); err != nil {
return nil, err
}
// note that we only support little endian squashfs for now
if bytes.HasPrefix(header, []byte{'h', 's', 'q', 's'}) {
return snapfs.New(path), nil
}
if strings.HasPrefix(string(header), "!<arch>\ndebian") {
return clickdeb.Open(path)
}
return nil, fmt.Errorf("unknown header %v", header)
}