support setting configfile via envvar FROGMOUTH_CFG_FILE

frogmouth/data/config.py

@@ -1,7 +1,7 @@
 """Provides code for loading/saving configuration."""
-
 from __future__ import annotations
 
+import os
 from dataclasses import asdict, dataclass, field
 from functools import lru_cache
 from json import dumps, loads
@@ -29,13 +29,21 @@ class Config:
 def config_file() -> Path:
     """Get the path to the configuration file.
 
+    The location of the configfile can be explicitly set by the
+    environment variable ``FROGMOUTH_CFG_FILE``.
+    When this env-var is not set, we default to XDG-directories.
+
     Returns:
         The path to the configuration file.
 
     Note:
-        As a side-effect, the configuration directory will be created if it
+        As a side-effect, the default configuration xdg-directory will be created if it
         does not exist.
     """
+
+    if cfg_file := os.getenv("FROGMOUTH_CFG_FILE"):
+        return Path(cfg_file)
+
     (config_dir := xdg_config_home() / ORGANISATION_NAME / PACKAGE_NAME).mkdir(
         parents=True, exist_ok=True
     )

frogmouth/data/data_directory.py

@@ -1,5 +1,5 @@
 """Provides a function for working out the data directory location."""
-
+import os
 from pathlib import Path
 
 from xdg import xdg_data_home
@@ -10,12 +10,20 @@
 def data_directory() -> Path:
     """Get the location of the data directory.
 
+    The location of the configfile can be explicitly set by the
+    environment variable ``FROGMOUTH_DATA_DIR``.
+    When this env-var is not set, we default to XDG-directories.
+
     Returns:
         The location of the data directory.
 
     Note:
-        As a side effect, if the directory doesn't exist it will be created.
+        As a side effect, if the xdg-directory doesn't exist it will be created.
     """
+
+    if target_directory := os.getenv("FROGMOUTH_DATA_DIR"):
+        return Path(target_directory)
+
     (target_directory := xdg_data_home() / ORGANISATION_NAME / PACKAGE_NAME).mkdir(
         parents=True, exist_ok=True
     )