class Environment(Component, ComponentManager):
"""The environment loads plugins """
commands = ExtensionPoint(IShellCommandProvider)
console_objects = ExtensionPoint(IShellConsoleObjectProvider)
env_objects = ExtensionPoint(IEnvObjectProvider)
def __init__(self, config=None, entry_point=None, plugins=None,
logger=None, locals=None):
"""Initialize the Dustbowl environment.
@param config: the absolute path to a configuration file.
@param entry_point: The entry point used to locate plugins.
@param plugins: a list of tuples containing paths in which to look for
plugins and a boolean indicating whether or not
plugins loaded from the specified path should be
auto-enabled.
@param logger: a Python logger instance.
``sys.path`` will be automatically added to the list of plugin
directories. All entries of ``sys.path`` will not be auto-enabled.
"""
ComponentManager.__init__(self)
self.setup_config(config)
self.setup_log(logger)
# Load plugins
self.plugin_data = dict()
if not plugins:
plugins = list()
self.load_modules(plugins, entry_point=entry_point)
if locals:
self.parent_locals = locals
for provider in self.console_objects:
for key, value in provider.get_console_objects():
self.add_console_object(key, value, provider.__class__.__name__)
continue
continue
for provider in self.env_objects:
for key, value in provider.get_env_objects():
self.add_env_object(key, value, provider.__class__.__name__)
continue
continue
def component_activated(self, component):
"""Initialize additional member variables for components.
Every component activated through the `Environment` object gets three
member variables: `env` (the environment object), `config` (the
environment configuration) and `log` (a logger object)."""
component.env = self
component.config = self.config
component.log = self.log
def is_component_enabled(self, cls):
"""Implemented to only allow activation of components that are not
disabled in the configuration.
This is called by the `ComponentManager` base class when a component is
about to be activated. If this method returns false, the component does
not get activated."""
if not isinstance(cls, basestring):
component_name = (cls.__module__ + '.' + cls.__name__).lower()
else:
component_name = cls.lower()
for key, value in self.plugin_data.iteritems():
if component_name == key or component_name.startswith(key + '.'):
value['activated'] = True
return value['loaded']
return False
def setup_config(self, configpath):
"""Load the configuration file."""
self.config = Configuration(configpath)
def setup_log(self, logger):
"""Initialize the logging sub-system."""
if logger:
self.log = logger
else:
self.log = NullLogger()
def is_enabled(self, module_name):
""" Return whether a module is enabled in the config.
"""
for key, value in self.config.options('components'):
k = key.lower()
mod = module_name.lower()
if mod == k or k.endswith('*') and mod.startswith(k[:-1]):
return self.config.getbool('components', key)
return False
def load_modules(self, plugins=None, entry_point='dustbowl.modules'):
""" Load plugins """
def _log_error(item, e):
ue = format_exception(e)
if isinstance(e, DistributionNotFound):
self.log.debug('Skipping "%s": ("%s" not found)', item, ue)
elif isinstance(e, VersionConflict):
self.log.error('Skipping "%s": (version conflict "%s")',
item, ue)
elif isinstance(e, UnknownExtra):
self.log.error('Skipping "%s": (unknown extra "%s")', item, ue)
elif isinstance(e, ImportError):
self.log.error('Skipping "%s": (can\'t import "%s")', item, ue)
else:
self.log.error('Skipping "%s": (error "%s")', item, ue)
ws = pkg_resources.WorkingSet(sys.path)
# Look for core modules
ws.add_entry(os.path.dirname(
pkg_resources.resource_filename(__name__, '')))
for entry in ws.iter_entry_points(entry_point):
if entry.name.startswith('dustbowl.plugins'):
entry_data = {
'entry' : entry,
'loaded' : False,
'activated' : False,
'auto_enable' : True,
}
self.plugin_data.setdefault(entry.name, entry_data)
# Look for modules in sys.path
for p in sys.path:
ws.add_entry(p)
for entry in ws.iter_entry_points(entry_point):
entry_data = {
'entry' : entry,
'loaded' : False,
'activated' : False,
'auto_enable' : False,
}
self.plugin_data.setdefault(entry.name, entry_data)
# Look for modules from plugin dir specified in the config or on the
# command line
distributions, errors = ws.find_plugins(
pkg_resources.Environment(plugins))
for dist in distributions:
self.log.debug('Found plugin %s at %s', dist, dist.location)
ws.add(dist)
for entry in ws.iter_entry_points(entry_point):
entry_data = {
'entry' : entry,
'loaded' : False,
'activated' : False,
'auto_enable' : False,
}
self.plugin_data.setdefault(entry.name, entry_data)
for entry_name, data in self.plugin_data.iteritems():
if data['auto_enable'] or self.is_enabled(entry_name):
try:
self.log.debug('Loading %s from %s', data['entry'].name,
data['entry'].dist)
# We need to make sure the distribution is on the path
# before we can load it.
data['entry'].dist.activate()
data['entry'].load(require=True)
data['loaded'] = True
except (ImportError, DistributionNotFound, VersionConflict,
UnknownExtra), e:
# Print the last traceback to the debug buffer
_log_error(data['entry'], e)
continue
for dist, e in errors.iteritems():
_log_error(dist, e)
def setup_log(self, logger):
"""Initialize the logging sub-system."""
if logger:
self.log = logger
else:
self.log = NullLogger()
