import os import sys import time import subprocess import threading from itertools import chain from werkzeug._internal import _log from werkzeug._compat import PY2, iteritems, text_type def _iter_module_files(): """This iterates over all relevant Python files. It goes through all loaded files from modules, all files in folders of already loaded modules as well as all files reachable through a package. """ # The list call is necessary on Python 3 in case the module # dictionary modifies during iteration. for module in list(sys.modules.values()): if module is None: continue filename = getattr(module, '__file__', None) if filename: old = None while not os.path.isfile(filename): old = filename filename = os.path.dirname(filename) if filename == old: break else: if filename[-4:] in ('.pyc', '.pyo'): filename = filename[:-1] yield filename def _find_observable_paths(extra_files=None): """Finds all paths that should be observed.""" rv = set(os.path.abspath(x) for x in sys.path) for filename in extra_files or (): rv.add(os.path.dirname(os.path.abspath(filename))) for module in list(sys.modules.values()): fn = getattr(module, '__file__', None) if fn is None: continue fn = os.path.abspath(fn) rv.add(os.path.dirname(fn)) return _find_common_roots(rv) def _get_args_for_reloading(): """Returns the executable. This contains a workaround for windows if the executable is incorrectly reported to not have the .exe extension which can cause bugs on reloading. """ rv = [sys.executable] py_script = sys.argv[0] if os.name == 'nt' and not os.path.exists(py_script) and \ os.path.exists(py_script + '.exe'): py_script += '.exe' rv.append(py_script) rv.extend(sys.argv[1:]) return rv def _find_common_roots(paths): """Out of some paths it finds the common roots that need monitoring.""" paths = [x.split(os.path.sep) for x in paths] root = {} for chunks in sorted(paths, key=len, reverse=True): node = root for chunk in chunks: node = node.setdefault(chunk, {}) node.clear() rv = set() def _walk(node, path): for prefix, child in iteritems(node): _walk(child, path + (prefix,)) if not node: rv.add('/'.join(path)) _walk(root, ()) return rv class ReloaderLoop(object): name = None # monkeypatched by testsuite. wrapping with `staticmethod` is required in # case time.sleep has been replaced by a non-c function (e.g. by # `eventlet.monkey_patch`) before we get here _sleep = staticmethod(time.sleep) def __init__(self, extra_files=None, interval=1): self.extra_files = set(os.path.abspath(x) for x in extra_files or ()) self.interval = interval def run(self): pass def restart_with_reloader(self): """Spawn a new Python interpreter with the same arguments as this one, but running the reloader thread. """ while 1: _log('info', ' * Restarting with %s' % self.name) args = _get_args_for_reloading() new_environ = os.environ.copy() new_environ['WERKZEUG_RUN_MAIN'] = 'true' # a weird bug on windows. sometimes unicode strings end up in the # environment and subprocess.call does not like this, encode them # to latin1 and continue. if os.name == 'nt' and PY2: for key, value in iteritems(new_environ): if isinstance(value, text_type): new_environ[key] = value.encode('iso-8859-1') exit_code = subprocess.call(args, env=new_environ, close_fds=False) if exit_code != 3: return exit_code def trigger_reload(self, filename): self.log_reload(filename) sys.exit(3) def log_reload(self, filename): filename = os.path.abspath(filename) _log('info', ' * Detected change in %r, reloading' % filename) class StatReloaderLoop(ReloaderLoop): name = 'stat' def run(self): mtimes = {} while 1: for filename in chain(_iter_module_files(), self.extra_files): try: mtime = os.stat(filename).st_mtime except OSError: continue old_time = mtimes.get(filename) if old_time is None: mtimes[filename] = mtime continue elif mtime > old_time: self.trigger_reload(filename) self._sleep(self.interval) class WatchdogReloaderLoop(ReloaderLoop): def __init__(self, *args, **kwargs): ReloaderLoop.__init__(self, *args, **kwargs) from watchdog.observers import Observer from watchdog.events import FileSystemEventHandler self.observable_paths = set() def _check_modification(filename): if filename in self.extra_files: self.trigger_reload(filename) dirname = os.path.dirname(filename) if dirname.startswith(tuple(self.observable_paths)): if filename.endswith(('.pyc', '.pyo')): self.trigger_reload(filename[:-1]) elif filename.endswith('.py'): self.trigger_reload(filename) class _CustomHandler(FileSystemEventHandler): def on_created(self, event): _check_modification(event.src_path) def on_modified(self, event): _check_modification(event.src_path) def on_moved(self, event): _check_modification(event.src_path) _check_modification(event.dest_path) def on_deleted(self, event): _check_modification(event.src_path) reloader_name = Observer.__name__.lower() if reloader_name.endswith('observer'): reloader_name = reloader_name[:-8] reloader_name += ' reloader' self.name = reloader_name self.observer_class = Observer self.event_handler = _CustomHandler() self.should_reload = False def trigger_reload(self, filename): # This is called inside an event handler, which means throwing # SystemExit has no effect. # https://github.com/gorakhargosh/watchdog/issues/294 self.should_reload = True self.log_reload(filename) def run(self): watches = {} observer = self.observer_class() observer.start() while not self.should_reload: to_delete = set(watches) paths = _find_observable_paths(self.extra_files) for path in paths: if path not in watches: try: watches[path] = observer.schedule( self.event_handler, path, recursive=True) except OSError: # Clear this path from list of watches We don't want # the same error message showing again in the next # iteration. watches[path] = None to_delete.discard(path) for path in to_delete: watch = watches.pop(path, None) if watch is not None: observer.unschedule(watch) self.observable_paths = paths self._sleep(self.interval) sys.exit(3) reloader_loops = { 'stat': StatReloaderLoop, 'watchdog': WatchdogReloaderLoop, } try: __import__('watchdog.observers') except ImportError: reloader_loops['auto'] = reloader_loops['stat'] else: reloader_loops['auto'] = reloader_loops['watchdog'] def run_with_reloader(main_func, extra_files=None, interval=1, reloader_type='auto'): """Run the given function in an independent python interpreter.""" import signal reloader = reloader_loops[reloader_type](extra_files, interval) signal.signal(signal.SIGTERM, lambda *args: sys.exit(0)) try: if os.environ.get('WERKZEUG_RUN_MAIN') == 'true': t = threading.Thread(target=main_func, args=()) t.setDaemon(True) t.start() reloader.run() else: sys.exit(reloader.restart_with_reloader()) except KeyboardInterrupt: pass