def mounts_from_meta()

in antlir/compiler/items/mount.py [0:0]

• 33 lines of code
• 8 McCabe index (conditional complexity)

def mounts_from_meta(volume_path: Path) -> Iterator[Mount]:
    """
    Returns a list of constructed `MountItem`s built from the a .meta/ dir
    directly under the provided path.
    """
    mounts_path = volume_path / META_MOUNTS_DIR
    if not mounts_path.exists():
        return

    for path, _next_dirs, _files in os.walk(
        # We are not `chroot`ed, so following links could access outside the
        # image; `followlinks=False` is the default -- explicit for safety.
        mounts_path,
        onerror=_raise,
        followlinks=False,
    ):
        relpath = Path(path).relpath(mounts_path)
        if relpath.basename() == MOUNT_MARKER:
            mountpoint = relpath.dirname()
            assert not mountpoint.endswith(b"/"), mountpoint

            # Deserialize the mount madness
            cfg = procfs_serde.deserialize_untyped(
                volume_path, Path(META_MOUNTS_DIR / relpath).decode()
            )

            # Convert config info proper types and create a Mount
            mount = Mount(
                mountpoint=mountpoint.decode(),
                build_source=BuildSource(**cfg.pop("build_source")),
                is_directory={"0": False, "1": True}[cfg.pop("is_directory")],
                runtime_source=(
                    RuntimeSource(**cfg.pop("runtime_source"))
                    if "runtime_source" in cfg
                    else None
                ),
                layer_publisher=(
                    LayerPublisher(**cfg.pop("layer_publisher"))
                    if "layer_publisher" in cfg
                    else None
                ),
            )

            assert not cfg, cfg
            yield mount