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import imp
import logging
from collections import defaultdict
from cloudcontrol.common.client.tags import Tag
from cloudcontrol.common.jobs import Job
from cloudcontrol.common.tql.db.helpers import taggify
logger = logging.getLogger(__name__)
def _tag_direct_use_error(*args, **kwargs):
raise RuntimeError('Plugins tags can\'t be called directly')
class Plugin(object):
""" Represent a loaded cloudcontrol plugin.
"""
def __init__(self, logger, tag_db, name, sha1, plugin_body):
self.logger = logger
self.name = name
self.sha1 = sha1
self.tag_db = tag_db
self.methods = {}
self.events = defaultdict(lambda: [])
self._load_module(plugin_body)
self.trigger('install', self)
def _load_module(self, plugin_body):
# load the code into a module:
module = imp.new_module(self.name)
module.logger = self.logger
module.tag = self._decorator_tag
module.method = self._decorator_method
module.on = self._decorator_event
try:
exec plugin_body in module.__dict__
except Exception as exc:
err_msg = 'Error during plugin installation (%s): %s' % (
self.name, exc)
# make sure all tags are stopped
self.tag_db.set_parent(None)
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raise RuntimeError(err_msg)
else:
# prevents module from being garbage collected
self.module = module
def _decorator_tag(self, ttl=-1, refresh=None, name=None):
def decorator(func):
tag = Tag(func.__name__ if name is None else name,
lambda: taggify(func()), ttl=ttl, refresh=refresh)
self.tag_db.add_tag(tag)
return _tag_direct_use_error
return decorator
def _decorator_method(self, name=None):
def decorator(func):
self.methods[func.__name__ if name is None else name] = func
return func
return decorator
def _decorator_event(self, event):
def decorator(func):
self.events[event].append(func)
return func
return decorator
def trigger(self, event, *args, **kwargs):
"""Trigger an event."""
for func in self.events[event]:
func(*args, **kwargs)
def uninstall(self):
self.trigger('uninstall')
# shutdown the tags database:
self.tag_db.set_parent(None)
class PluginMethodJob(Job):
"""Job that run a plugin method."""
def job(self, plugin_name, method_name, method, method_kwargs):
kwargs_str = ', '.join(('%s=%s' % (k, v) for k, v in method_kwargs.iteritems()))
self.title = 'Plugin: %s.%s(%s)' % (plugin_name, method_name, kwargs_str)
try:
returned = method(self, **method_kwargs)
except Exception:
self.logger.exception('Error while executing method')
raise
if returned is not None:
self.attachment('output').write(returned)