envoy.base.utils: Add utils.is_tarlike (#26)

Signed-off-by: Ryan Northey <ryan@synca.io>

envoy.base.utils/VERSION

@@ -1 +1 @@
-0.0.2-dev
+0.0.2

envoy.base.utils/envoy/base/utils/__init__.py

@@ -10,11 +10,18 @@
 from configparser import ConfigParser
 from contextlib import (
     ExitStack, contextmanager, redirect_stderr, redirect_stdout)
-from typing import Callable, Iterator, List, Optional, Union
+from typing import Callable, Iterator, List, Optional, Set, Union
 
 import yaml
 
 
+# See here for a list of known tar file extensions:
+#   https://en.wikipedia.org/wiki/Tar_(computing)#Suffixes_for_compressed_files
+# not all are listed here, and some extensions may require additional software
+# to handle. This list can be updated as required
+TAR_EXTS: Set[str] = {"tar", "tar.gz", "tar.xz", "tar.bz2"}
+
+
 class ExtractError(Exception):
     pass
 
@@ -136,3 +143,13 @@ def to_yaml(
     path = pathlib.Path(path)
     path.write_text(yaml.dump(data))
     return path
+
+
+def is_tarlike(path: Union[pathlib.Path, str]) -> bool:
+    """Returns a bool based on whether a file looks like a tar file depending
+    on its file extension.
+
+    This allows for a provided path to save to, to dynamically be either
+    considered a directory (to create) or a tar file (to create).
+    """
+    return any(str(path).endswith(ext) for ext in TAR_EXTS)

envoy.base.utils/tests/test_utils.py

@@ -226,3 +226,15 @@ def test_util_to_yaml(patches):
     assert (
         list(m_plib.Path.call_args)
         == [("PATH", ), {}])
+
+
+@pytest.mark.parametrize(
+    "path",
+    ["x.foo", "x.bar", "x.tar", "x.tar.xz", "x.xz"])
+def test_is_tarlike(patches, path):
+    matches = False
+    for ext in utils.TAR_EXTS:
+        if path.endswith(ext):
+            matches = True
+            break
+    assert utils.is_tarlike(path) == matches