"""IPython extension to reload modules before executing user code. ``autoreload`` reloads modules automatically before entering the execution of code typed at the IPython prompt. This makes for example the following workflow possible: .. sourcecode:: ipython In [1]: %load_ext autoreload In [2]: %autoreload 2 In [3]: from foo import some_function In [4]: some_function() Out[4]: 42 In [5]: # open foo.py in an editor and change some_function to return 43 In [6]: some_function() Out[6]: 43 The module was reloaded without reloading it explicitly, and the object imported with ``from foo import ...`` was also updated. Usage ===== The following magic commands are provided: ``%autoreload`` Reload all modules (except those excluded by ``%aimport``) automatically now. ``%autoreload 0`` Disable automatic reloading. ``%autoreload 1`` Reload all modules imported with ``%aimport`` every time before executing the Python code typed. ``%autoreload 2`` Reload all modules (except those excluded by ``%aimport``) every time before executing the Python code typed. ``%aimport`` List modules which are to be automatically imported or not to be imported. ``%aimport foo`` Import module 'foo' and mark it to be autoreloaded for ``%autoreload 1`` ``%aimport -foo`` Mark module 'foo' to not be autoreloaded. Caveats ======= Reloading Python modules in a reliable way is in general difficult, and unexpected things may occur. ``%autoreload`` tries to work around common pitfalls by replacing function code objects and parts of classes previously in the module with new versions. This makes the following things to work: - Functions and classes imported via 'from xxx import foo' are upgraded to new versions when 'xxx' is reloaded. - Methods and properties of classes are upgraded on reload, so that calling 'c.foo()' on an object 'c' created before the reload causes the new code for 'foo' to be executed. Some of the known remaining caveats are: - Replacing code objects does not always succeed: changing a @property in a class to an ordinary method or a method to a member variable can cause problems (but in old objects only). - Functions that are removed (eg. via monkey-patching) from a module before it is reloaded are not upgraded. - C extension modules cannot be reloaded, and so cannot be autoreloaded. """ from __future__ import print_function skip_doctest = True #----------------------------------------------------------------------------- # Copyright (C) 2000 Thomas Heller # Copyright (C) 2008 Pauli Virtanen # Copyright (C) 2012 The IPython Development Team # # Distributed under the terms of the BSD License. The full license is in # the file COPYING, distributed as part of this software. #----------------------------------------------------------------------------- # # This IPython module is written by Pauli Virtanen, based on the autoreload # code by Thomas Heller. #----------------------------------------------------------------------------- # Imports #----------------------------------------------------------------------------- import os import sys import traceback import types import weakref try: # Reload is not defined by default in Python3. reload except NameError: from imp import reload from IPython.utils import pyfile from IPython.utils.py3compat import PY3 #------------------------------------------------------------------------------ # Autoreload functionality #------------------------------------------------------------------------------ class ModuleReloader(object): enabled = False """Whether this reloader is enabled""" failed = {} """Modules that failed to reload: {module: mtime-on-failed-reload, ...}""" modules = {} """Modules specially marked as autoreloadable.""" skip_modules = {} """Modules specially marked as not autoreloadable.""" check_all = True """Autoreload all modules, not just those listed in 'modules'""" old_objects = {} """(module-name, name) -> weakref, for replacing old code objects""" def mark_module_skipped(self, module_name): """Skip reloading the named module in the future""" try: del self.modules[module_name] except KeyError: pass self.skip_modules[module_name] = True def mark_module_reloadable(self, module_name): """Reload the named module in the future (if it is imported)""" try: del self.skip_modules[module_name] except KeyError: pass self.modules[module_name] = True def aimport_module(self, module_name): """Import a module, and mark it reloadable Returns ------- top_module : module The imported module if it is top-level, or the top-level top_name : module Name of top_module """ self.mark_module_reloadable(module_name) __import__(module_name) top_name = module_name.split('.')[0] top_module = sys.modules[top_name] return top_module, top_name def check(self, check_all=False): """Check whether some modules need to be reloaded.""" if not self.enabled and not check_all: return if check_all or self.check_all: modules = sys.modules.keys() else: modules = self.modules.keys() for modname in modules: m = sys.modules.get(modname, None) if modname in self.skip_modules: continue if not hasattr(m, '__file__'): continue if m.__name__ == '__main__': # we cannot reload(__main__) continue filename = m.__file__ path, ext = os.path.splitext(filename) if ext.lower() == '.py': pyc_filename = pyfile.cache_from_source(filename) py_filename = filename else: pyc_filename = filename try: py_filename = pyfile.source_from_cache(filename) except ValueError: continue try: pymtime = os.stat(py_filename).st_mtime if pymtime <= os.stat(pyc_filename).st_mtime: continue if self.failed.get(py_filename, None) == pymtime: continue except OSError: continue try: superreload(m, reload, self.old_objects) if py_filename in self.failed: del self.failed[py_filename] except: print("[autoreload of %s failed: %s]" % ( modname, traceback.format_exc(1)), file=sys.stderr) self.failed[py_filename] = pymtime #------------------------------------------------------------------------------ # superreload #------------------------------------------------------------------------------ if PY3: func_attrs = ['__code__', '__defaults__', '__doc__', '__closure__', '__globals__', '__dict__'] else: func_attrs = ['func_code', 'func_defaults', 'func_doc', 'func_closure', 'func_globals', 'func_dict'] def update_function(old, new): """Upgrade the code object of a function""" for name in func_attrs: try: setattr(old, name, getattr(new, name)) except (AttributeError, TypeError): pass def update_class(old, new): """Replace stuff in the __dict__ of a class, and upgrade method code objects""" for key in old.__dict__.keys(): old_obj = getattr(old, key) try: new_obj = getattr(new, key) except AttributeError: # obsolete attribute: remove it try: delattr(old, key) except (AttributeError, TypeError): pass continue if update_generic(old_obj, new_obj): continue try: setattr(old, key, getattr(new, key)) except (AttributeError, TypeError): pass # skip non-writable attributes def update_property(old, new): """Replace get/set/del functions of a property""" update_generic(old.fdel, new.fdel) update_generic(old.fget, new.fget) update_generic(old.fset, new.fset) def isinstance2(a, b, typ): return isinstance(a, typ) and isinstance(b, typ) UPDATE_RULES = [ (lambda a, b: isinstance2(a, b, type), update_class), (lambda a, b: isinstance2(a, b, types.FunctionType), update_function), (lambda a, b: isinstance2(a, b, property), update_property), ] if PY3: UPDATE_RULES.extend([(lambda a, b: isinstance2(a, b, types.MethodType), lambda a, b: update_function(a.__func__, b.__func__)), ]) else: UPDATE_RULES.extend([(lambda a, b: isinstance2(a, b, types.ClassType), update_class), (lambda a, b: isinstance2(a, b, types.MethodType), lambda a, b: update_function(a.im_func, b.im_func)), ]) def update_generic(a, b): for type_check, update in UPDATE_RULES: if type_check(a, b): update(a, b) return True return False class StrongRef(object): def __init__(self, obj): self.obj = obj def __call__(self): return self.obj def superreload(module, reload=reload, old_objects={}): """Enhanced version of the builtin reload function. superreload remembers objects previously in the module, and - upgrades the class dictionary of every old class in the module - upgrades the code object of every old function and method - clears the module's namespace before reloading """ # collect old objects in the module for name, obj in module.__dict__.items(): if not hasattr(obj, '__module__') or obj.__module__ != module.__name__: continue key = (module.__name__, name) try: old_objects.setdefault(key, []).append(weakref.ref(obj)) except TypeError: # weakref doesn't work for all types; # create strong references for 'important' cases if not PY3 and isinstance(obj, types.ClassType): old_objects.setdefault(key, []).append(StrongRef(obj)) # reload module try: # clear namespace first from old cruft old_dict = module.__dict__.copy() old_name = module.__name__ module.__dict__.clear() module.__dict__['__name__'] = old_name module.__dict__['__loader__'] = old_dict['__loader__'] except (TypeError, AttributeError, KeyError): pass try: module = reload(module) except: # restore module dictionary on failed reload module.__dict__.update(old_dict) raise # iterate over all objects and update functions & classes for name, new_obj in module.__dict__.items(): key = (module.__name__, name) if key not in old_objects: continue new_refs = [] for old_ref in old_objects[key]: old_obj = old_ref() if old_obj is None: continue new_refs.append(old_ref) update_generic(old_obj, new_obj) if new_refs: old_objects[key] = new_refs else: del old_objects[key] return module #------------------------------------------------------------------------------ # IPython connectivity #------------------------------------------------------------------------------ from IPython.core.hooks import TryNext from IPython.core.magic import Magics, magics_class, line_magic @magics_class class AutoreloadMagics(Magics): def __init__(self, *a, **kw): super(AutoreloadMagics, self).__init__(*a, **kw) self._reloader = ModuleReloader() self._reloader.check_all = False @line_magic def autoreload(self, parameter_s=''): r"""%autoreload => Reload modules automatically %autoreload Reload all modules (except those excluded by %aimport) automatically now. %autoreload 0 Disable automatic reloading. %autoreload 1 Reload all modules imported with %aimport every time before executing the Python code typed. %autoreload 2 Reload all modules (except those excluded by %aimport) every time before executing the Python code typed. Reloading Python modules in a reliable way is in general difficult, and unexpected things may occur. %autoreload tries to work around common pitfalls by replacing function code objects and parts of classes previously in the module with new versions. This makes the following things to work: - Functions and classes imported via 'from xxx import foo' are upgraded to new versions when 'xxx' is reloaded. - Methods and properties of classes are upgraded on reload, so that calling 'c.foo()' on an object 'c' created before the reload causes the new code for 'foo' to be executed. Some of the known remaining caveats are: - Replacing code objects does not always succeed: changing a @property in a class to an ordinary method or a method to a member variable can cause problems (but in old objects only). - Functions that are removed (eg. via monkey-patching) from a module before it is reloaded are not upgraded. - C extension modules cannot be reloaded, and so cannot be autoreloaded. """ if parameter_s == '': self._reloader.check(True) elif parameter_s == '0': self._reloader.enabled = False elif parameter_s == '1': self._reloader.check_all = False self._reloader.enabled = True elif parameter_s == '2': self._reloader.check_all = True self._reloader.enabled = True @line_magic def aimport(self, parameter_s='', stream=None): """%aimport => Import modules for automatic reloading. %aimport List modules to automatically import and not to import. %aimport foo Import module 'foo' and mark it to be autoreloaded for %autoreload 1 %aimport -foo Mark module 'foo' to not be autoreloaded for %autoreload 1 """ modname = parameter_s if not modname: to_reload = self._reloader.modules.keys() to_reload.sort() to_skip = self._reloader.skip_modules.keys() to_skip.sort() if stream is None: stream = sys.stdout if self._reloader.check_all: stream.write("Modules to reload:\nall-except-skipped\n") else: stream.write("Modules to reload:\n%s\n" % ' '.join(to_reload)) stream.write("\nModules to skip:\n%s\n" % ' '.join(to_skip)) elif modname.startswith('-'): modname = modname[1:] self._reloader.mark_module_skipped(modname) else: top_module, top_name = self._reloader.aimport_module(modname) # Inject module to user namespace self.shell.push({top_name: top_module}) def pre_run_code_hook(self, ip): if not self._reloader.enabled: raise TryNext try: self._reloader.check() except: pass def load_ipython_extension(ip): """Load the extension in IPython.""" auto_reload = AutoreloadMagics(ip) ip.register_magics(auto_reload) ip.set_hook('pre_run_code_hook', auto_reload.pre_run_code_hook)