Support custom config file locations via environment variables

CHANGELOG.md

@@ -11,6 +11,7 @@
 - Add support for SketchyBar (via @LarsRefsgaard)
 - Add support for nvm (via @Wxh16144)
 - Add support for PHPStorm 2023.3 (via @damosse31)
+- Add support for changing the config file location via environment variables (via @northisup)
 
 ## Mackup 0.8.40
 

doc/README.md

@@ -1,14 +1,24 @@
 # Configuration
 
 All the configuration is done in a file named `.mackup.cfg` stored at the
-root of your home folder.
+root of your home folder. This location can be overridden via environment
+variables.
 
 To configure Mackup, create a file named `.mackup.cfg` in your home directory.
 
 ```bash
 vi ~/.mackup.cfg
 ```
 
+### Configuration file location
+
+Config files are searched in the following order. If none is found, Mackup will
+use the default config location of `~/.mackup.cfg`
+
+- `~/.mackup.cfg`
+- `$MACKUP_CONFIG`
+- `$XDG_CONFIG_HOME/mackup/mackup.cfg` or `~/.config/mackup/mackup.cfg`
+
 ## Storage
 
 You can specify the storage type Mackup will use to store your configuration

mackup/config.py

@@ -2,17 +2,17 @@
 
 import os
 import os.path
+from pathlib import Path
 
 from .constants import (
     CUSTOM_APPS_DIR,
-    MACKUP_BACKUP_PATH,
-    MACKUP_CONFIG_FILE,
     ENGINE_DROPBOX,
+    ENGINE_FS,
     ENGINE_GDRIVE,
     ENGINE_ICLOUD,
-    ENGINE_FS,
+    MACKUP_BACKUP_PATH,
+    MACKUP_CONFIG_FILE,
 )
-
 from .utils import (
     error,
     get_dropbox_folder_location,
@@ -140,17 +140,64 @@ def _setup_parser(self, filename=None):
         """
         assert isinstance(filename, str) or filename is None
 
-        # If we are not overriding the config filename
-        if not filename:
-            filename = MACKUP_CONFIG_FILE
-
         parser = configparser.ConfigParser(
             allow_no_value=True, inline_comment_prefixes=(";", "#")
         )
-        parser.read(os.path.join(os.path.join(os.environ["HOME"], filename)))
+        parser.read(self._best_config_path(filename))
 
         return parser
 
+    def _best_config_path(self, filename=None):
+        """
+        If no filename is provided, we try to find one in according to the following
+        order, note that we will always check the original default of `~/.mackup.cfg`
+        first before checking the other options:
+
+        - ~/.mackup.cfg
+        - $MACKUP_CONFIG
+        - $XDG_CONFIG_HOME/mackup/mackup.cfg
+        - ~/.config/mackup/mackup.cfg
+
+        if none of these files exist, we create ~/.mackup.cfg
+
+        Args:
+            filename (_type_, optional): _description_. Defaults to None.
+
+        Returns:
+            str: the absolute path to the config file
+        """
+        assert isinstance(filename, str) or filename is None
+
+        # If we are not overriding the config filename
+        if not filename:
+            default = Path.home() / MACKUP_CONFIG_FILE
+            search_paths = [
+                # 1. the default config file is ~/.mackup.cfg
+                default,
+                # 2. check for the MACKUP_CONFIG envvar
+                Path(os.environ.get("MACKUP_CONFIG", "")).expanduser(),
+                # 3. check for a config file in the XDG_CONFIG_HOME directory
+                (
+                    Path(os.environ.get("XDG_CONFIG_HOME", "~/.config")).expanduser()
+                    / "mackup"
+                    / MACKUP_CONFIG_FILE.lstrip(".")
+                ),
+            ]
+            filename = next((p for p in search_paths if p.is_file()), default)
+        else:
+            filename = Path.home() / filename
+
+        try:
+            # Make sure the config file is in the home directory
+            filename.relative_to(Path.home())
+        except ValueError:
+            error(
+                f"The config file '{filename}' is not in your home directory. Aborting."
+            )
+
+        # return the absolute path to the config file
+        return str(filename.absolute())
+
     def _warn_on_old_config(self):
         """Warn the user if an old config format is detected."""
         # Is an old section in the config file?

tests/test_config.py

@@ -1,20 +1,72 @@
-import unittest
+import os
 import os.path
+import unittest
+from pathlib import Path
 
+from mackup.config import Config, ConfigError
 from mackup.constants import (
     ENGINE_DROPBOX,
+    ENGINE_FS,
     ENGINE_GDRIVE,
     ENGINE_ICLOUD,
-    ENGINE_FS,
+    MACKUP_CONFIG_FILE,
 )
-from mackup.config import Config, ConfigError
+
+
+def assert_correct_config_read(testtype):
+    assert testtype == Config()._parser.get("test", "testtype")
 
 
 class TestConfig(unittest.TestCase):
     def setUp(self):
         realpath = os.path.dirname(os.path.realpath(__file__))
         os.environ["HOME"] = os.path.join(realpath, "fixtures")
 
+        # these may be set on some user's systems
+        os.environ.pop("XDG_CONFIG_HOME", None)
+        os.environ.pop("MACKUP_CONFIG", None)
+
+    def test_config_envvar(self):
+        os.environ["MACKUP_CONFIG"] = "~/mackup-envarcheck.cfg"
+        assert_correct_config_read("test_config_envvar")
+
+    def test_config_xdg(self):
+        os.environ["XDG_CONFIG_HOME"] = "~/xdg-config-home/"
+        assert_correct_config_read("test_config_xdg")
+
+    def test_config_find_correct_default(self):
+        config_path = Path.home() / MACKUP_CONFIG_FILE
+
+        try:
+            # create a default config file, this must be cleaned up after the test
+            config_path.write_text(f"[test]\ntesttype = test_config_default")
+
+            # nothing else set, should find the default file
+            assert_correct_config_read("test_config_default")
+
+            # set MACKUP_CONFIG, but should still find the default file
+            os.environ["MACKUP_CONFIG"] = "~/mackup-envarcheck.cfg"
+            assert_correct_config_read("test_config_default")
+
+            # set XDG_CONFIG_HOME, but should still find the default file
+            os.environ["XDG_CONFIG_HOME"] = "~/xdg-config-home/"
+            assert_correct_config_read("test_config_default")
+        except Exception:
+            raise
+        finally:
+            config_path.unlink(missing_ok=True)
+
+        assert config_path.exists() is False
+
+    def test_config_finds_correct_envvar(self):
+        # set XDG_CONFIG_HOME, but should still find the default file
+        os.environ["XDG_CONFIG_HOME"] = "~/xdg-config-home/"
+        assert_correct_config_read("test_config_xdg")
+
+        # set MACKUP_CONFIG, but should still find the default file
+        os.environ["MACKUP_CONFIG"] = "~/mackup-envarcheck.cfg"
+        assert_correct_config_read("test_config_envvar")
+
     def test_config_no_config(self):
         cfg = Config()