| # |
| # Copyright (C) 2016 Codethink Limited |
| # |
| # This program is free software; you can redistribute it and/or |
| # modify it under the terms of the GNU Lesser General Public |
| # License as published by the Free Software Foundation; either |
| # version 2 of the License, or (at your option) any later version. |
| # |
| # This library is distributed in the hope that it will be useful, |
| # but WITHOUT ANY WARRANTY; without even the implied warranty of |
| # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| # Lesser General Public License for more details. |
| # |
| # You should have received a copy of the GNU Lesser General Public |
| # License along with this library. If not, see <http://www.gnu.org/licenses/>. |
| # |
| # Authors: |
| # Tristan Van Berkom <tristan.vanberkom@codethink.co.uk> |
| |
| import os |
| import inspect |
| |
| from ._exceptions import PluginError |
| from . import utils |
| |
| |
| # A Context for loading plugin types |
| # |
| # Args: |
| # plugin_base (PluginBase): The main PluginBase object to work with |
| # base_type (type): A base object type for this context |
| # site_plugin_path (str): Path to where buildstream keeps plugins |
| # plugin_origins (list): Data used to search for plugins |
| # |
| # Since multiple pipelines can be processed recursively |
| # within the same interpretor, it's important that we have |
| # one context associated to the processing of a given pipeline, |
| # this way sources and element types which are particular to |
| # a given BuildStream project are isolated to their respective |
| # Pipelines. |
| # |
| class PluginContext(): |
| |
| def __init__(self, plugin_base, base_type, site_plugin_path, plugin_origins=None, dependencies=None): |
| |
| # The plugin kinds which were loaded |
| self.loaded_dependencies = [] |
| |
| # |
| # Private members |
| # |
| self._dependencies = dependencies |
| self._base_type = base_type # The base class plugins derive from |
| self._types = {} # Plugin type lookup table by kind |
| self._plugin_origins = plugin_origins or [] |
| |
| # The PluginSource object |
| self._plugin_base = plugin_base |
| self._site_source = plugin_base.make_plugin_source(searchpath=site_plugin_path) |
| self._alternate_sources = {} |
| |
| # lookup(): |
| # |
| # Fetches a type loaded from a plugin in this plugin context |
| # |
| # Args: |
| # kind (str): The kind of Plugin to create |
| # |
| # Returns: the type associated with the given kind |
| # |
| # Raises: PluginError |
| # |
| def lookup(self, kind): |
| return self._ensure_plugin(kind) |
| |
| def _get_local_plugin_source(self, path): |
| if ('local', path) not in self._alternate_sources: |
| # key by a tuple to avoid collision |
| source = self._plugin_base.make_plugin_source(searchpath=[path]) |
| # Ensure that sources never get garbage collected, |
| # as they'll take the plugins with them. |
| self._alternate_sources[('local', path)] = source |
| else: |
| source = self._alternate_sources[('local', path)] |
| return source |
| |
| def _get_pip_plugin_source(self, package_name, kind): |
| defaults = None |
| if ('pip', package_name) not in self._alternate_sources: |
| import pkg_resources |
| # key by a tuple to avoid collision |
| try: |
| package = pkg_resources.get_entry_info(package_name, |
| 'buildstream.plugins', |
| kind) |
| except pkg_resources.DistributionNotFound as e: |
| raise PluginError("Failed to load {} plugin '{}': {}" |
| .format(self._base_type.__name__, kind, e)) from e |
| |
| if package is None: |
| raise PluginError("Pip package {} does not contain a plugin named '{}'" |
| .format(package_name, kind)) |
| |
| location = package.dist.get_resource_filename( |
| pkg_resources._manager, |
| package.module_name.replace('.', os.sep) + '.py' |
| ) |
| |
| # Also load the defaults - required since setuptools |
| # may need to extract the file. |
| try: |
| defaults = package.dist.get_resource_filename( |
| pkg_resources._manager, |
| package.module_name.replace('.', os.sep) + '.yaml' |
| ) |
| except KeyError: |
| # The plugin didn't have an accompanying YAML file |
| defaults = None |
| |
| source = self._plugin_base.make_plugin_source(searchpath=[os.path.dirname(location)]) |
| self._alternate_sources[('pip', package_name)] = source |
| |
| else: |
| source = self._alternate_sources[('pip', package_name)] |
| |
| return source, defaults |
| |
| def _ensure_plugin(self, kind): |
| |
| if kind not in self._types: |
| # Check whether the plugin is specified in plugins |
| source = None |
| defaults = None |
| loaded_dependency = False |
| for origin in self._plugin_origins: |
| if kind not in origin['plugins']: |
| continue |
| |
| if origin['origin'] == 'local': |
| source = self._get_local_plugin_source(origin['path']) |
| elif origin['origin'] == 'pip': |
| source, defaults = self._get_pip_plugin_source(origin['package-name'], kind) |
| else: |
| raise PluginError("Failed to load plugin '{}': " |
| "Unexpected plugin origin '{}'" |
| .format(kind, origin['origin'])) |
| loaded_dependency = True |
| break |
| |
| # Fall back to getting the source from site |
| if not source: |
| if kind not in self._site_source.list_plugins(): |
| raise PluginError("No {} type registered for kind '{}'" |
| .format(self._base_type.__name__, kind)) |
| |
| source = self._site_source |
| |
| self._types[kind] = self._load_plugin(source, kind, defaults) |
| if loaded_dependency: |
| self.loaded_dependencies.append(kind) |
| |
| return self._types[kind] |
| |
| def _load_plugin(self, source, kind, defaults): |
| |
| try: |
| plugin = source.load_plugin(kind) |
| |
| if not defaults: |
| plugin_file = inspect.getfile(plugin) |
| plugin_dir = os.path.dirname(plugin_file) |
| plugin_conf_name = "{}.yaml".format(kind) |
| defaults = os.path.join(plugin_dir, plugin_conf_name) |
| |
| except ImportError as e: |
| raise PluginError("Failed to load {} plugin '{}': {}" |
| .format(self._base_type.__name__, kind, e)) from e |
| |
| try: |
| plugin_type = plugin.setup() |
| except AttributeError as e: |
| raise PluginError("{} plugin '{}' did not provide a setup() function" |
| .format(self._base_type.__name__, kind)) from e |
| except TypeError as e: |
| raise PluginError("setup symbol in {} plugin '{}' is not a function" |
| .format(self._base_type.__name__, kind)) from e |
| |
| self._assert_plugin(kind, plugin_type) |
| self._assert_version(kind, plugin_type) |
| return (plugin_type, defaults) |
| |
| def _assert_plugin(self, kind, plugin_type): |
| if kind in self._types: |
| raise PluginError("Tried to register {} plugin for existing kind '{}' " |
| "(already registered {})" |
| .format(self._base_type.__name__, kind, self._types[kind].__name__)) |
| try: |
| if not issubclass(plugin_type, self._base_type): |
| raise PluginError("{} plugin '{}' returned type '{}', which is not a subclass of {}" |
| .format(self._base_type.__name__, kind, |
| plugin_type.__name__, |
| self._base_type.__name__)) |
| except TypeError as e: |
| raise PluginError("{} plugin '{}' returned something that is not a type (expected subclass of {})" |
| .format(self._base_type.__name__, kind, |
| self._base_type.__name__)) from e |
| |
| def _assert_version(self, kind, plugin_type): |
| |
| # Now assert BuildStream version |
| bst_major, bst_minor = utils.get_bst_version() |
| |
| if bst_major < plugin_type.BST_REQUIRED_VERSION_MAJOR or \ |
| (bst_major == plugin_type.BST_REQUIRED_VERSION_MAJOR and |
| bst_minor < plugin_type.BST_REQUIRED_VERSION_MINOR): |
| raise PluginError("BuildStream {}.{} is too old for {} plugin '{}' (requires {}.{})" |
| .format( |
| bst_major, bst_minor, |
| self._base_type.__name__, kind, |
| plugin_type.BST_REQUIRED_VERSION_MAJOR, |
| plugin_type.BST_REQUIRED_VERSION_MINOR)) |
