Skip to content


Subversion checkout URL

You can clone with
Download ZIP
Fetching contributors…
Cannot retrieve contributors at this time
251 lines (219 sloc) 8.85 KB
#!/usr/bin/env python
# Copyright 2009 Facebook
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
"""A module to automatically restart the server when a module is modified.
Most applications should not call this module directly. Instead, pass the
keyword argument ``debug=True`` to the `tornado.web.Application` constructor.
This will enable autoreload mode as well as checking for changes to templates
and static resources.
This module depends on IOLoop, so it will not work in WSGI applications
and Google AppEngine. It also will not work correctly when HTTPServer's
multi-process mode is used.
from __future__ import with_statement
import functools
import logging
import os
import pkgutil
import sys
import types
import subprocess
from tornado import ioloop
from tornado import process
import signal
except ImportError:
signal = None
def start(io_loop=None, check_time=500):
"""Restarts the process automatically when a module is modified.
We run on the I/O loop, and restarting is a destructive operation,
so will terminate any pending requests.
io_loop = io_loop or ioloop.IOLoop.instance()
add_reload_hook(functools.partial(_close_all_fds, io_loop))
modify_times = {}
callback = functools.partial(_reload_on_update, modify_times)
scheduler = ioloop.PeriodicCallback(callback, check_time, io_loop=io_loop)
def wait():
"""Wait for a watched file to change, then restart the process.
Intended to be used at the end of scripts like unit test runners,
to run the tests again after any source file changes (but see also
the command-line interface in `main`)
io_loop = ioloop.IOLoop()
_watched_files = set()
def watch(filename):
"""Add a file to the watch list.
All imported modules are watched by default.
_reload_hooks = []
def add_reload_hook(fn):
"""Add a function to be called before reloading the process.
Note that for open file and socket handles it is generally
preferable to set the ``FD_CLOEXEC`` flag (using `fcntl` or
``) instead of using a reload
hook to close them.
def _close_all_fds(io_loop):
for fd in io_loop._handlers.keys():
except Exception:
_reload_attempted = False
def _reload_on_update(modify_times):
if _reload_attempted:
# We already tried to reload and it didn't work, so don't try again.
if process.task_id() is not None:
# We're in a child process created by fork_processes. If child
# processes restarted themselves, they'd all restart and then
# all call fork_processes again.
for module in sys.modules.values():
# Some modules play games with sys.modules (e.g. email/
# in the standard library), and occasionally this can cause strange
# failures in getattr. Just ignore anything that's not an ordinary
# module.
if not isinstance(module, types.ModuleType): continue
path = getattr(module, "__file__", None)
if not path: continue
if path.endswith(".pyc") or path.endswith(".pyo"):
path = path[:-1]
_check_file(modify_times, path)
for path in _watched_files:
_check_file(modify_times, path)
def _check_file(modify_times, path):
modified = os.stat(path).st_mtime
except Exception:
if path not in modify_times:
modify_times[path] = modified
if modify_times[path] != modified:"%s modified; restarting server", path)
def _reload():
global _reload_attempted
_reload_attempted = True
for fn in _reload_hooks:
if hasattr(signal, "setitimer"):
# Clear the alarm signal set by
# ioloop.set_blocking_log_threshold so it doesn't fire
# after the exec.
signal.setitimer(signal.ITIMER_REAL, 0, 0)
if sys.platform == 'win32':
# os.execv is broken on Windows and can't properly parse command line
# arguments and executable name if they contain whitespaces. subprocess
# fixes that behavior.
subprocess.Popen([sys.executable] + sys.argv)
os.execv(sys.executable, [sys.executable] + sys.argv)
except OSError:
# Mac OS X versions prior to 10.6 do not support execv in
# a process that contains multiple threads. Instead of
# re-executing in the current process, start a new one
# and cause the current process to exit. This isn't
# ideal since the new process is detached from the parent
# terminal and thus cannot easily be killed with ctrl-C,
# but it's better than not being able to autoreload at
# all.
# Unfortunately the errno returned in this case does not
# appear to be consistent, so we can't easily check for
# this error specifically.
os.spawnv(os.P_NOWAIT, sys.executable,
[sys.executable] + sys.argv)
_USAGE = """\
python -m tornado.autoreload -m [args...]
python -m tornado.autoreload path/to/ [args...]
def main():
"""Command-line wrapper to re-run a script whenever its source changes.
Scripts may be specified by filename or module name::
python -m tornado.autoreload -m tornado.test.runtests
python -m tornado.autoreload tornado/test/
Running a script with this wrapper is similar to calling
`tornado.autoreload.wait` at the end of the script, but this wrapper
can catch import-time problems like syntax errors that would otherwise
prevent the script from reaching its call to `wait`.
original_argv = sys.argv
sys.argv = sys.argv[:]
if len(sys.argv) >= 3 and sys.argv[1] == "-m":
mode = "module"
module = sys.argv[2]
del sys.argv[1:3]
elif len(sys.argv) >= 2:
mode = "script"
script = sys.argv[1]
sys.argv = sys.argv[1:]
print >>sys.stderr, _USAGE
if mode == "module":
import runpy
runpy.run_module(module, run_name="__main__", alter_sys=True)
elif mode == "script":
with open(script) as f:
global __file__
__file__ = script
# Use globals as our "locals" dictionary so that
# something that tries to import __main__ (e.g. the unittest
# module) will see the right things.
exec in globals(), globals()
except SystemExit, e:"Script exited with status %s", e.code)
except Exception, e:
logging.warning("Script exited with uncaught exception", exc_info=True)
if isinstance(e, SyntaxError):
else:"Script exited normally")
# restore sys.argv so subsequent executions will include autoreload
sys.argv = original_argv
if mode == 'module':
# runpy did a fake import of the module as __main__, but now it's
# no longer in sys.modules. Figure out where it is and watch it.
if __name__ == "__main__":
# If this module is run with "python -m tornado.autoreload", the current
# directory is automatically prepended to sys.path, but not if it is
# run as "path/to/tornado/". The processing for "-m" rewrites
# the former to the latter, so subsequent executions won't have the same
# path as the original. Modify os.environ here to ensure that the
# re-executed process will have the same path.
# Conversely, when run as path/to/tornado/, the directory
# containing gets added to the path, but we don't want
# tornado modules importable at top level, so remove it.
path_prefix = '.' + os.pathsep
if (sys.path[0] == '' and
not os.environ.get("PYTHONPATH", "").startswith(path_prefix)):
os.environ["PYTHONPATH"] = path_prefix + os.environ.get("PYTHONPATH", "")
elif sys.path[0] == os.path.dirname(__file__):
del sys.path[0]
Jump to Line
Something went wrong with that request. Please try again.