feat: add the ability to load plugins in config

henworth · henworth · commit 2fdea8909012 · 2025-01-07T11:13:40.000-05:00
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
@@ -13,7 +13,7 @@ feature request][issue]. It's great to hear about new ideas.
 
 If you are inclined to do so, you're welcome to [fork][fork] Dotbot, work on
 implementing the feature yourself, and submit a patch. In this case, it's
-*highly recommended* that you first [open an issue][issue] describing your
+_highly recommended_ that you first [open an issue][issue] describing your
 enhancement to get early feedback on the new feature that you are implementing.
 This will help avoid wasted efforts and ensure that your work is incorporated
 into the code base.
@@ -35,7 +35,7 @@ Want to hack on Dotbot? Awesome!
 If there are [open issues][issues], you're more than welcome to work on those -
 this is probably the best way to contribute to Dotbot. If you have your own
 ideas, that's great too! In that case, before working on substantial changes to
-the code base, it is *highly recommended* that you first [open an issue][issue]
+the code base, it is _highly recommended_ that you first [open an issue][issue]
 describing what you intend to work on.
 
 **Patches are generally submitted as pull requests.** Patches are also
@@ -50,6 +50,45 @@ demonstrate that the bug is fixed (or that the feature works).
 See the [Dotbot development guide][development] to learn how to run the tests,
 type checking, and more.
 
+When preparing a patch, it's recommended that you add unit tests
+that demonstrate the bug is fixed (or that the feature works).
+You can run the tests on your local machine by installing the `dev` extras.
+The steps below do this using a virtual environment:
+
+```shell
+# Create a local virtual environment
+$ python -m venv .venv
+
+# Activate the virtual environment
+# Cygwin, Linux, and MacOS:
+$ . .venv/bin/activate
+# Windows Powershell:
+$ & .venv\Scripts\Activate.ps1
+
+# Update pip and setuptools
+(.venv) $ python -m pip install -U pip setuptools
+
+# Install dotbot and its development dependencies
+(.venv) $ python -m pip install -e .[dev]
+
+# Run the unit tests
+(.venv) $ tox
+```
+
+If you prefer to run the tests in an isolated container using Docker, you can
+do so with the following:
+
+```shell
+docker run -it --rm -v "${PWD}:/dotbot" -w /dotbot python:3.10-alpine /bin/sh
+```
+
+If the machine you are running Docker on has SELinux in the enforcing state, you
+will have to disable that on the container. This can be done by adding
+`--security-opt label:disable` to the above command.
+
+After spawning the container, follow the same instructions as above (create a
+virtualenv, ..., run the tests).
+
 ---
 
 If you have any questions about anything, feel free to [ask][email]!
diff --git a/README.md b/README.md
@@ -429,12 +429,27 @@ should do something and return whether or not it completed successfully.
 All built-in Dotbot directives are written as plugins that are loaded by
 default, so those can be used as a reference when writing custom plugins.
 
-Plugins are loaded using the `--plugin` and `--plugin-dir` options, using
-either absolute paths or paths relative to the base directory. It is
-recommended that these options are added directly to the `install` script.
-
 See [here][plugins] for a current list of plugins.
 
+#### Format
+
+Plugins can be loaded either by the command-line arguments `--plugin` or
+`--plugin-dir` or by the `plugins` directive. Each of these take either
+absolute paths or paths relative to the base directory.
+
+When using command-line arguments to load multiple plugins you must add
+one argument for each plugin to be loaded. It is recommended to place
+these command-line arguments directly in the `install` script.
+
+The `plugins` config directive is specified as an array of paths to load.
+
+#### Example
+
+```yaml
+- plugins:
+    - dotbot-plugins/dotbot-template 
+```
+
 ## Command-line Arguments
 
 Dotbot takes a number of command-line arguments; you can run Dotbot with
diff --git a/src/dotbot/cli.py b/src/dotbot/cli.py
@@ -9,7 +9,7 @@
 from dotbot.config import ConfigReader, ReadingError
 from dotbot.dispatcher import Dispatcher, DispatchError, _all_plugins
 from dotbot.messenger import Level, Messenger
-from dotbot.plugins import Clean, Create, Link, Shell
+from dotbot.plugins import Clean, Create, Link, Plugins, Shell
 from dotbot.util import module
 
 
@@ -101,7 +101,7 @@ def main() -> None:
         plugins = []
         plugin_directories = list(options.plugin_dirs)
         if not options.disable_built_in_plugins:
-            plugins.extend([Clean, Create, Link, Shell])
+            plugins.extend([Clean, Create, Link, Plugins, Shell])
         plugin_paths = []
         for directory in plugin_directories:
             plugin_paths.extend(glob.glob(os.path.join(directory, "*.py")))
diff --git a/src/dotbot/dispatcher.py b/src/dotbot/dispatcher.py
@@ -62,6 +62,7 @@ def dispatch(self, tasks: List[Dict[str, Any]]) -> bool:
                     self._context.set_defaults(task[action])  # replace, not update
                     handled = True
                     # keep going, let other plugins handle this if they want
+
                 for plugin in self._plugins:
                     if plugin.can_handle(action):
                         try:
@@ -76,14 +77,27 @@ def dispatch(self, tasks: List[Dict[str, Any]]) -> bool:
                             self._log.error(f"An error was encountered while executing action {action}")
                             self._log.debug(str(err))
                             if self._exit:
-                                # There was an execption exit
+                                # There was an exception exit
                                 return False
+
+                if action == "plugins":
+                    # Create a list of loaded plugin names
+                    loaded_plugins = [
+                        plugin.__class__.__name__ for plugin in self._plugins
+                    ]
+
+                    # Load plugins that haven't been loaded yet
+                    for plugin in Plugin.__subclasses__():
+                        if plugin.__name__ not in loaded_plugins:
+                            self._plugins.append(plugin(self._context))
+
                 if not handled:
                     success = False
                     self._log.error(f"Action {action} not handled")
                     if self._exit:
                         # Invalid action exit
                         return False
+
         return success
 
 
diff --git a/src/dotbot/plugins/__init__.py b/src/dotbot/plugins/__init__.py
@@ -1,6 +1,7 @@
 from dotbot.plugins.clean import Clean
 from dotbot.plugins.create import Create
 from dotbot.plugins.link import Link
+from dotbot.plugins.plugins import Plugins
 from dotbot.plugins.shell import Shell
 
-__all__ = ["Clean", "Create", "Link", "Shell"]
+__all__ = ["Clean", "Create", "Link", "Plugins", "Shell"]
diff --git a/src/dotbot/plugins/plugins.py b/src/dotbot/plugins/plugins.py
@@ -0,0 +1,47 @@
+import glob
+import os
+from typing import Any
+
+from dotbot.plugin import Plugin
+from dotbot.util import module
+
+
+class Plugins(Plugin):
+    """
+    Load plugins from a list of paths.
+    """
+
+    _directive = "plugins"
+    _has_shown_override_message = False
+
+    def can_handle(self, directive: str) -> bool:
+        return directive == self._directive
+
+    def handle(self, directive: str, data: Any) -> bool:
+        if directive != self._directive:
+            raise ValueError(f"plugins cannot handle directive {directive}")
+        return self._process_plugins(data)
+
+    def _process_plugins(self, data: Any) -> bool:
+        success = True
+        plugin_paths = []
+        for item in data:
+            self._log.lowinfo(f"Loading plugin from {item}")
+
+            plugin_path_globs = glob.glob(os.path.join(item, "*.py"))
+            if not plugin_path_globs:
+                success = False
+                self._log.warning(f"Failed to load plugin from {item}")
+            else:
+                for plugin_path in plugin_path_globs:
+                    plugin_paths.append(plugin_path)
+
+        for plugin_path in plugin_paths:
+            abspath = os.path.abspath(plugin_path)
+            module.load(abspath)
+
+        if success:
+            self._log.info("All commands have been executed")
+        else:
+            self._log.error("Some commands were not successfully executed")
+        return success
diff --git a/tests/dotbot_plugin_config_file.py b/tests/dotbot_plugin_config_file.py
@@ -0,0 +1,19 @@
+"""Test that a plugin can be loaded by config file.
+
+This file is copied to a location with the name "config_file.py",
+and is then loaded from within the `test_cli.py` code.
+"""
+
+import os.path
+
+import dotbot
+
+
+class ConfigFile(dotbot.Plugin):
+    def can_handle(self, directive):
+        return directive == "plugin_config_file"
+
+    def handle(self, directive, data):
+        with open(os.path.abspath(os.path.expanduser("~/flag")), "w") as file:
+            file.write("config file plugin loading works")
+        return True
