feat: Resolve Path to both Local and Remote Source

Added ready method to resolve path to a local or remote stub. In the case of a remote, the source is
first downloaded/unpacked into a temporary directory.

micropy/stubs/__init__.py

@@ -8,6 +8,7 @@
 to stub files/frozen modules and their usage in MicropyCli
 """
 
+from . import source
 from .stubs import StubManager
 
-__all__ = ['StubManager']
+__all__ = ['StubManager', 'source']

micropy/stubs/source.py

@@ -9,18 +9,50 @@
 """
 
 
+import io
+import shutil
+import tarfile
+import tempfile
+from contextlib import contextmanager
+from functools import partial
+from pathlib import Path
+
+import requests
+
 from micropy import utils
 from micropy.logger import Log
 
 
 class StubSource:
-    """Stub Source Base Class"""
+    """Abstract Base Class for Stub Sources"""
 
     def __init__(self, location):
         self.location = location
         _name = self.__class__.__name__
         self.log = Log.add_logger(_name)
 
+    @contextmanager
+    def ready(self, path=None, teardown=None):
+        """Yields prepared Stub Source
+
+        Allows StubSource subclasses to have a preperation
+        method before providing a local path to itself.
+
+        Args:
+            path (str, optional): path to stub source.
+                Defaults to location.
+            teardown (func, optional): callback to execute on exit.
+                Defaults to None.
+
+        Yields:
+            Resolved PathLike object to stub source
+        """
+        _path = path or self.location
+        path = Path(_path).resolve()
+        yield path
+        if teardown:
+            teardown()
+
 
 class LocalStubSource(StubSource):
     """Stub Source Subclass for local locations
@@ -51,6 +83,42 @@ def __init__(self, url):
         location = utils.ensure_valid_url(url)
         return super().__init__(location)
 
+    def _unpack_archive(self, file_bytes, path):
+        """Unpack archive from bytes buffer
+
+        Args:
+            file_bytes (bytes): Byte array to extract from
+                Must be from tarfile with gzip compression
+            path (str): path to extract file to
+
+        Returns:
+            path: path extracted to
+        """
+        tar_bytes_obj = io.BytesIO(file_bytes)
+        with tarfile.open(fileobj=tar_bytes_obj, mode="r:gz") as tar:
+            tar.extractall(path)
+        return path
+
+    def ready(self):
+        """Retrieves and unpacks source
+
+        Prepares remote stub resource by downloading and
+        unpacking it into a temporary directory.
+        This directory is removed on exit of the superclass
+        context manager
+
+        Returns:
+            callable: StubSource.ready parent method
+        """
+        tmp_dir = tempfile.mkdtemp()
+        tmp_path = Path(tmp_dir)
+        filename = utils.get_url_filename(self.location).split(".tar.gz")[0]
+        outpath = tmp_path / filename
+        resp = requests.get(self.location)
+        source_path = self._unpack_archive(resp.content, outpath)
+        teardown = partial(shutil.rmtree, tmp_path)
+        return super().ready(path=source_path, teardown=teardown)
+
 
 def get_source(location, **kwargs):
     """Factory for StubSource Instance