Completely rewritten plugin loader to accept absolute modules, or single file paths (6d464349) · Commits · OpenFlexure / openflexure-microscope-server

openflexure_microscope/plugins/init.py

+2 −2

Original line number	Diff line number	Diff line
		__all__ = ['search_plugin_dirs', 'find_plugins', 'load_plugin', 'PluginMount', 'MicroscopePlugin']
		__all__ = ['module_from_file', 'load_plugin_class', 'load_plugin_module', 'class_from_map', 'PluginMount', 'MicroscopePlugin']

		from .loader import search_plugin_dirs, find_plugins, load_plugin, PluginMount, MicroscopePlugin
		No newline at end of file
		from .loader import module_from_file, load_plugin_class, load_plugin_module, class_from_map, PluginMount, MicroscopePlugin
		No newline at end of file

openflexure_microscope/plugins/loader.py

+85 −124

Original line number	Diff line number	Diff line
		import importlib
		import os
		import warnings
		import inspect
		import logging

		from openflexure_microscope.config import USER_CONFIG_DIR

		MAIN_MODULE = '__init__'
		HERE = os.path.abspath(os.path.dirname(__file__))
		DEFAULT_PLUGIN_PATH = os.path.join(HERE, 'default')
		USER_PLUGIN_DIR = os.path.join(USER_CONFIG_DIR, "plugins")
		class bcolors:
		HEADER = '\033[95m'
		OKBLUE = '\033[94m'
		OKGREEN = '\033[92m'
		WARNING = '\033[93m'
		FAIL = '\033[91m'
		ENDC = '\033[0m'
		BOLD = '\033[1m'
		UNDERLINE = '\033[4m'


		def search_plugin_dirs(plugin_paths, include_default=True):
		"""
		Search through, and load from, a list of plugin directories.

		Args:
		plugin_paths (list): List of strings of plugin directories.
		include_default (bool): Also load plugins from the module default directory (DEFAULT_PLUGIN_PATH, USER_PLUGIN_DIR)
		"""
		global DEFAULT_PLUGIN_PATH, USER_PLUGIN_DIR

		if not os.path.exists(USER_PLUGIN_DIR): # If user config file already exists
		os.makedirs(USER_PLUGIN_DIR)

		if include_default: # If including default plugins
		plugin_paths.append(DEFAULT_PLUGIN_PATH) # Add default directory to the search paths
		plugin_paths.append(USER_PLUGIN_DIR) # Add user directory to the search paths

		logging.debug(plugin_paths)

		plugins = [] # List of loaded plugins
		for plugin_dir in plugin_paths: # For each plugin directory
		logging.debug("Searching {}".format(plugin_dir))
		plugins.extend(find_plugins(plugin_dir)) # Find plugin folders, and load into list

		return plugins


		def find_plugins_legacy(plugin_dir):
		"""
		Find all plugins residing within a directory
		def module_from_file(plugin_path):
		# Expand environment variables in path string
		plugin_path = os.path.expandvars(plugin_path)
		# Expand user directory in path string
		plugin_path = os.path.expanduser(plugin_path)

		Args:
		plugin_dir (str): String of directory to be searched
		"""
		plugins = []
		plugins_folders = os.listdir(plugin_dir)

		loader_details = (
		importlib.machinery.SourceFileLoader,
		importlib.machinery.SOURCE_SUFFIXES
		)

		for i in plugins_folders:
		plugin_folder = os.path.join(plugin_dir, i)
		logging.info(plugin_folder)

		if not os.path.isdir(plugin_folder): # If plugin folder doesn't exist
		continue # Skip this iteration
		if not MAIN_MODULE + '.py' in os.listdir(plugin_folder): # If no __init__ file in plugin folder
		continue # Skip this iteration

		module_spec = importlib.machinery.FileFinder(plugin_folder, loader_details).find_spec(MAIN_MODULE)
		# Check if the path is to a file
		if not os.path.isfile(plugin_path):
		logging.warning(bcolors.FAIL + "No valid plugin found at {}.".format(plugin_path) + bcolors.ENDC)
		return None, None, None

		plugins.append(module_spec)
		return plugins


		def find_plugins(plugin_dir):
		"""
		Find all plugins residing within a directory
		else:
		# Get name of plugin from the file
		plugin_name = os.path.splitext(os.path.basename(plugin_path))[0]

		Args:
		plugin_dir (str): String of directory to be searched
		"""
		plugins = []
		plugins_folders = os.listdir(plugin_dir)
		plugin_spec = importlib.util.spec_from_file_location(plugin_name, plugin_path)
		plugin_module = importlib.util.module_from_spec(plugin_spec)

		loader_details = (
		importlib.machinery.SourceFileLoader,
		importlib.machinery.SOURCE_SUFFIXES
		)
		return plugin_spec, plugin_module, plugin_name

		for i in plugins_folders:
		plugin_folder = os.path.join(plugin_dir, i)
		logging.info(plugin_folder)

		if not os.path.isdir(plugin_folder): # If plugin folder doesn't exist
		continue # Skip this iteration
		if not MAIN_MODULE + '.py' in os.listdir(plugin_folder): # If no __init__ file in plugin folder
		continue # Skip this iteration
		def load_plugin_module(plugin_path):
		# First, try importing from standard modules
		try:
		plugin_module = importlib.import_module(plugin_path)
		except ModuleNotFoundError:
		plugin_spec, plugin_module, plugin_name = module_from_file(plugin_path)

		module_spec = importlib.machinery.FileFinder(plugin_folder, loader_details).find_spec(MAIN_MODULE)
		# If a valid plugin was found
		if plugin_spec and plugin_module:
		# Execute the module, so we have access to it
		plugin_spec.loader.exec_module(plugin_module)
		else:
		plugin_name = plugin_path.split('.')[-1]

		plugins.append(module_spec)
		return plugins
		return plugin_module, plugin_name


		def load_plugin(module_spec):
		"""
		Load a source file from a given spec.
		def load_plugin_class(plugin_path, plugin_class_name):
		plugin_module, plugin_name = load_plugin_module(plugin_path)
		if plugin_module:
		# Now try to extract the class
		try:
		plugin_class = getattr(plugin_module, plugin_class_name)
		except AttributeError:
		logging.warning(bcolors.FAIL + "Class {} does not exist in plugin {}. Skipping.".format(plugin_class_name, plugin_path) + bcolors.ENDC)
		return None, None
		else:
		return plugin_class, plugin_name
		else:
		return None, None

		Args:
		module_spec: Module spec of module to be returned
		"""
		module = importlib.util.module_from_spec(module_spec)
		module_spec.loader.exec_module(module)
		return module

		def class_from_map(plugin_map):
		plugin_arr = plugin_map.split(':')

		def load_plugin_legacy(module_spec):
		"""
		Load a source file from a given spec.
		if not len(plugin_arr) == 2:
		logging.warning(bcolors.WARNING + "Malformed plugin map {}. Skipping.".format(plugin_map) + bcolors.ENDC)
		return None, None
		else:
		return load_plugin_class(*plugin_arr)

		Args:
		module_spec: Module spec of module to be returned
		"""
		module = importlib.util.module_from_spec(module_spec)
		module_spec.loader.exec_module(module)
		return module

		class PluginMount(object):
		"""
		@@ -130,44 +87,45 @@ class PluginMount(object):
		"""
		def __init__(self, parent):
		self.parent = parent
		self.plugins = []
		print("Creating plugin mount")

		def attach(self, plugin_module):
		@property
		def members(self):
		plugin_array = []
		for obj_name in dir(self):
		if not obj_name == "plugins" and not obj_name[:2] == '__':
		obj = getattr(self, obj_name)
		if isinstance(obj, MicroscopePlugin):
		plugin_members = [member for member in inspect.getmembers(obj) if not member[0][:2] == '__']
		plugin_info = (obj_name, plugin_members)
		plugin_array.append(plugin_info)
		return plugin_array

		def attach(self, plugin_map):
		"""
		Attach a MicroscopePlugin instance to the plugin mount.

		Args:
		plugin_module: A loaded module to be attached. Module can be loaded using :py:meth:`openflexure_microscope.plugins.load_plugin`
		plugin_map (str): A plugin map describing the file or module to load a MicroscopePlugin child from. Maps should be in the format 'module.to.load:ClassName' or '/path/to/file:ClassName'.
		"""
		print("LOADING MODULE {}".format(plugin_module.__name__))
		plugin_class, plugin_name = class_from_map(plugin_map)

		if hasattr(plugin_module, 'PLUGINS') and isinstance(plugin_module.PLUGINS, dict):
		if plugin_class and plugin_name:
		plugin_object = plugin_class()

		for plugin_name, plugin_class in plugin_module.PLUGINS.items():
		if hasattr(self, plugin_name): # If a plugin with the same name is already attached.
		logging.warning(bcolors.WARNING + "A plugin named {} has already been loaded. Skipping {}.".format(plugin_name, plugin_map) + bcolors.ENDC)

		plugin_object = plugin_class()
		if hasattr(self, plugin_name):
		warnings.warn("A plugin named {} has already been loaded. Skipping {}.".format(plugin_name, plugin_class))
		else:
		elif isinstance(plugin_object, MicroscopePlugin): # If plugin_object is an instance of MicroscopePlugin
		# Attach plugin_object to the plugin mount
		setattr(self, plugin_name, plugin_object)
		self.plugins.append((plugin_name, plugin_object))

		# Grant plugin access to the hardware
		assert(isinstance(plugin_object, MicroscopePlugin))
		plugin_object.microscope = self.parent

		print("Adding plugin: {}".format(plugin_name))
		else:
		warnings.warn("No valid PLUGINS dictionary found in {}".format(plugin_module))


		class PluginGroup():
		"""
		A class used to group plugin methods within a PluginMount.

		Currently useless aside from creating a namespace in which plugin methods will reside.
		"""
		def __init__(self):
		pass
		logging.info(bcolors.OKGREEN + "Plugin {} loaded as {}.".format(plugin_map, plugin_name) + bcolors.ENDC)


		class MicroscopePlugin():
		@@ -177,5 +135,8 @@ class MicroscopePlugin():
		Initially only defines an empty object for microscope. All plugins
		must be an instance of this class to successfully attach to PluginMount.
		"""

		api_views = {} # Initially empty dictionary of API views associated with the plugin

		def __init__(self):
		self.microscope = None #: :py:class:`openflexure_microscope.microscope.Microscope`: Microscope object