matthew/enhanced-discord.py
1
0
Fork 0
Code Issues 4 Pull Requests 21 Projects Releases Wiki Activity

[commands] Add Bot.reload_extension for atomic loading.

Browse Source 
Also do atomic loading in Bot.load_extension
This commit is contained in:
Rapptz 2019-03-19 06:21:39 -04:00
parent d221ca5f7d
commit 26e9b5bfac
2 changed files with 109 additions and 47 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

149
discord/ext/commands/bot.py
View File

@ -523,6 +523,65 @@ class BotBase(GroupMixin):
# extensions
def _remove_module_references(self, name):
# find all references to the module
# remove the cogs registered from the module
for cogname, cog in self._cogs.copy().items():
if _is_submodule(name, cog.__module__):
self.remove_cog(cogname)
# remove all the commands from the module
for cmd in self.all_commands.copy().values():
if cmd.module is not None and _is_submodule(name, cmd.module):
if isinstance(cmd, GroupMixin):
cmd.recursively_remove_all_commands()
self.remove_command(cmd.name)
# remove all the listeners from the module
for event_list in self.extra_events.copy().values():
remove = []
for index, event in enumerate(event_list):
if event.__module__ is not None and _is_submodule(name, event.__module__):
remove.append(index)
for index in reversed(remove):
del event_list[index]
def _call_module_finalizers(self, lib, key):
try:
func = getattr(lib, 'teardown')
except AttributeError:
pass
else:
try:
func(self)
except Exception:
pass
finally:
self._extensions.pop(key, None)
sys.modules.pop(key, None)
name = lib.__name__
for module in list(sys.modules.keys()):
if _is_submodule(name, module):
del sys.modules[module]
def _load_from_module_spec(self, lib, key):
# precondition: key not in self._extensions
try:
setup = getattr(lib, 'setup')
except AttributeError:
del sys.modules[key]
raise discord.ClientException('extension {!r} ({!r}) does not have a setup function.'.format(key, lib))
try:
setup(self)
except Exception:
self._remove_module_references(lib.__name__)
self._call_module_finalizers(lib, key)
raise
else:
self._extensions[key] = lib
def load_extension(self, name):
"""Loads an extension.
@ -546,19 +605,16 @@ class BotBase(GroupMixin):
The extension does not have a setup function.
ImportError
The extension could not be imported.
Exception
Any other exception raised by the extension will be raised back
to the caller.
"""
if name in self._extensions:
return
lib = importlib.import_module(name)
if not hasattr(lib, 'setup'):
del lib
del sys.modules[name]
raise discord.ClientException('extension does not have a setup function')
lib.setup(self)
self._extensions[name] = lib
self._load_from_module_spec(lib, name)
def unload_extension(self, name):
"""Unloads an extension.
@ -583,49 +639,56 @@ class BotBase(GroupMixin):
if lib is None:
return
lib_name = lib.__name__
self._remove_module_references(lib.__name__)
self._call_module_finalizers(lib, name)
# find all references to the module
def reload_extension(self, name):
"""Atomically reloads an extension.
# remove the cogs registered from the module
for cogname, cog in self._cogs.copy().items():
if _is_submodule(lib_name, cog.__module__):
self.remove_cog(cogname)
This replaces the extension with the same extension, only refreshed. This is
equivalent to a :meth:`unload_extension` followed by a :meth:`load_extension`
except done in an atomic way. That is, if an operation fails mid-reload then
the bot will roll-back to the prior working state.
# remove all the commands from the module
for cmd in self.all_commands.copy().values():
if cmd.module is not None and _is_submodule(lib_name, cmd.module):
if isinstance(cmd, GroupMixin):
cmd.recursively_remove_all_commands()
self.remove_command(cmd.name)
Parameters
------------
name: :class:`str`
The extension name to reload. It must be dot separated like
regular Python imports if accessing a sub-module. e.g.
``foo.test`` if you want to import ``foo/test.py``.
# remove all the listeners from the module
for event_list in self.extra_events.copy().values():
remove = []
for index, event in enumerate(event_list):
if event.__module__ is not None and _is_submodule(lib_name, event.__module__):
remove.append(index)
Raises
-------
Exception
Any exception raised by the extension will be raised back
to the caller.
"""
for index in reversed(remove):
del event_list[index]
lib = self._extensions.get(name)
if lib is None:
return
# get the previous module states from sys modules
modules = {
name: module
for name, module in sys.modules.items()
if _is_submodule(lib.__name__, name)
}
try:
func = getattr(lib, 'teardown')
except AttributeError:
pass
else:
try:
func(self)
except Exception:
pass
finally:
# finally remove the import..
del lib
del self._extensions[name]
del sys.modules[name]
for module in list(sys.modules.keys()):
if _is_submodule(lib_name, module):
del sys.modules[module]
# Unload and then load the module...
self._remove_module_references(lib.__name__)
self._call_module_finalizers(lib, name)
self.load_extension(name)
except Exception as e:
# if the load failed, the remnants should have been
# cleaned from the load_extension function call
# so let's load it from our old compiled library.
self._load_from_module_spec(lib, name)
# revert sys.modules back to normal and raise back to caller
sys.modules.update(modules)
raise
@property
def extensions(self):

7
docs/ext/commands/extensions.rst
View File

@ -41,14 +41,13 @@ In this example we define a simple command, and when the extension is loaded thi
Reloading
-----------
The act of reloading an extension is actually quite simple -- it is as simple as unloading it and then reloading it.
When you make a change to the extension and want to reload the references, the library comes with a function to do this for you, :meth:`Bot.reload_extension`.
.. code-block:: python3
>>> bot.unload_extension('hello')
>>> bot.load_extension('hello')
>>> bot.reload_extension('hello')
Once we remove and load the extension, any changes that we did will be applied upon load. This is useful if we want to add or remove functionality without restarting our bot.
Once the extension reloads, any changes that we did will be applied. This is useful if we want to add or remove functionality without restarting our bot. If an error occurred during the reloading process, the bot will pretend as if the reload never happened.
Cleaning Up
-------------