use importlib.resources for config.templates

CHANGES

@@ -3,7 +3,13 @@
 ==============================
 
 2024-??-??      0.9.1
+orbeckst
 
+* templates in `config.templates` are now stored as
+  `importlib.resources.abc.Traversable` (PosixPath-like) objects instead of
+  strings of paths to files in the file system because we switched from
+  pkg_resources to importlib.resources for managing access to included files
+  (#282)
 * fixed reporting of failures of GromacsCommand and DeprecationWarnings for use
   of \s in regular expression strings (#285)
 

gromacs/config.py

@@ -232,8 +232,7 @@
 import sys
 
 from configparser import ConfigParser
-
-from pkg_resources import resource_filename, resource_listdir
+from importlib import resources
 
 from . import utilities
 
@@ -307,37 +306,36 @@
 
 
 def _generate_template_dict(dirname):
-    """Generate a list of included files *and* extract them to a temp space.
+    """Generate a list of included files *and* make them available.
+
+    Template files are stored inside the package. They are made available as
+    :class:` importlib.resources.abc.Traversable` object with
+    :mod:`pathlib.Path`-like methods. They can normally be read with the usual
+    :func:`open` function but if a real file needs to be present, use
+    :func:`importlib.resources.as_file`.
+
+    All template entries are stored in :data:`config.templates`.
+
+    .. SeeAlso:: importlib.resources
 
-    Templates have to be extracted from the egg because they are used
-    by external code. All template filenames are stored in
-    :data:`config.templates`.
     """
     return dict(
-        (resource_basename(fn), resource_filename(__name__, dirname + "/" + fn))
-        for fn in resource_listdir(__name__, dirname)
-        if not fn.endswith("~")
+        (entry.name, entry)
+        for entry in resources.files(__name__).joinpath(dirname).iterdir()
+        if not entry.name.endswith(("~", "__pycache__", "__init__.py"))
     )
 
 
-def resource_basename(resource):
-    """Last component of a resource (which always uses '/' as sep)."""
-    if resource.endswith("/"):
-        resource = resource[:-1]
-    parts = resource.split("/")
-    return parts[-1]
-
-
 templates = _generate_template_dict("templates")
 """*GromacsWrapper* comes with a number of templates for run input files
 and queuing system scripts. They are provided as a convenience and
 examples but **WITHOUT ANY GUARANTEE FOR CORRECTNESS OR SUITABILITY FOR
 ANY PURPOSE**.
 
-All template filenames are stored in
-:data:`gromacs.config.templates`. Templates have to be extracted from
-the GromacsWrapper python egg file because they are used by external
-code: find the actual file locations from this variable.
+All templates are stored in :data:`gromacs.config.templates` as :class:`
+importlib.resources.abc.Traversable` objects with :mod:`pathlib.Path`-like
+methods. They can normally be read with the usual :func:`open` function but if
+a real file needs to be present, use :func:`importlib.resources.as_file`.
 
 **Gromacs mdp templates**
 
@@ -357,6 +355,7 @@ def resource_basename(resource):
    The queing system scripts are highly specific and you will need to add your
    own into :data:`gromacs.config.qscriptdir`.
    See :mod:`gromacs.qsub` for the format and how these files are processed.
+
 """
 
 #: The default template for SGE/PBS run scripts.