utils.py: migrate from pkg_resources to importlib_resources

The former is being phased out, it already provokes (when? where?)

    DeprecationWarning: pkg_resources is deprecated as an API

bldr/bldr.py

@@ -1,3 +1,4 @@
+import importlib_resources
 import logging
 import os
 import pwd
@@ -10,7 +11,7 @@
 from tempfile import TemporaryDirectory
 
 from .docker_utils import create_docker_client, DockerImageBuilder, DockerImage, DockerContainer, DEFAULT_DOCKER_TIMEOUT
-from .utils import BLDRError, BLDRSetupFailed, escape_docker_image_tag, get_resource
+from .utils import BLDRError, BLDRSetupFailed, escape_docker_image_tag
 
 
 PRE_BUILD_HOOK = "/hooks/pre-build"
@@ -106,7 +107,10 @@ def _build_image(self, tag: str, control_file: Optional[Path] = None) -> DockerI
 
         with TemporaryDirectory(prefix="bldr_docker_dir_") as tmp_dir:
             docker_files_dir = Path(tmp_dir).joinpath('docker_files')
-            shutil.copytree(str(get_resource('.')), str(docker_files_dir))
+            with importlib_resources.as_file(
+                    importlib_resources.files().joinpath('data')
+            ) as resource_dir:
+                shutil.copytree(resource_dir, docker_files_dir)
             if control_file is None:
                 docker_files_dir.joinpath('control').write_text('')
             else:

bldr/utils.py

@@ -1,7 +1,6 @@
 import os
 import pwd
 from pathlib import Path
-from pkg_resources import resource_filename
 
 
 class BLDRError(Exception):
@@ -19,10 +18,6 @@ def __init__(self, msg: str, exitcode: int = 1) -> None:
         super().__init__(msg, exitcode)
 
 
-def get_resource(path: str) -> Path:
-    return Path(resource_filename('bldr', str(Path('data', path))))
-
-
 def escape_docker_image_tag(tag: str) -> str:
     return tag.replace(":", "-").replace("/", "-")
 

requirements.in

@@ -1,2 +1,3 @@
 docker
 dockerpty
+importlib_resources

test/unit/test_resources.py

@@ -0,0 +1,5 @@
+import importlib_resources
+
+
+def test_data_resource():
+    assert importlib_resources.files('bldr').joinpath('data').is_dir()