django/utils/autoreload.py

   1 # Autoreloading launcher.
   2 # Borrowed from Peter Hunt and the CherryPy project (http://www.cherrypy.org).
   3 # Some taken from Ian Bicking's Paste (http://pythonpaste.org/).
   4 #
   5 # Portions copyright (c) 2004, CherryPy Team (team@cherrypy.org)
   6 # All rights reserved.
   7 #
   8 # Redistribution and use in source and binary forms, with or without modification,
   9 # are permitted provided that the following conditions are met:
  10 #
  11 #     * Redistributions of source code must retain the above copyright notice,
  12 #       this list of conditions and the following disclaimer.
  13 #     * Redistributions in binary form must reproduce the above copyright notice,
  14 #       this list of conditions and the following disclaimer in the documentation
  15 #       and/or other materials provided with the distribution.
  16 #     * Neither the name of the CherryPy Team nor the names of its contributors
  17 #       may be used to endorse or promote products derived from this software
  18 #       without specific prior written permission.
  19 #
  20 # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  21 # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  22 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  23 # DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE
  24 # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25 # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  26 # SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  27 # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  28 # OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  29 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  30
  31 import os, sys, time
  32
  33 try:
  34     import thread
  35 except ImportError:
  36     import dummy_thread as thread
  37
  38 # This import does nothing, but it's necessary to avoid some race conditions
  39 # in the threading module. See http://code.djangoproject.com/ticket/2330 .
  40 try:
  41     import threading
  42 except ImportError:
  43     pass
  44
  45
  46 RUN_RELOADER = True
  47
  48 _mtimes = {}
  49 _win = (sys.platform == "win32")
  50
  51 def code_changed():
  52     global _mtimes, _win
  53     for filename in filter(lambda v: v, map(lambda m: getattr(m, "__file__", None), sys.modules.values())):
  54         if filename.endswith(".pyc") or filename.endswith(".pyo"):
  55             filename = filename[:-1]
  56         if not os.path.exists(filename):
  57             continue # File might be in an egg, so it can't be reloaded.
  58         stat = os.stat(filename)
  59         mtime = stat.st_mtime
  60         if _win:
  61             mtime -= stat.st_ctime
  62         if filename not in _mtimes:
  63             _mtimes[filename] = mtime
  64             continue
  65         if mtime != _mtimes[filename]:
  66             _mtimes = {}
  67             return True
  68     return False
  69
  70 def reloader_thread():
  71     while RUN_RELOADER:
  72         if code_changed():
  73             sys.exit(3) # force reload
  74         time.sleep(1)
  75
  76 def restart_with_reloader():
  77     while True:
  78         args = [sys.executable] + sys.argv
  79         if sys.platform == "win32":
  80             args = ['"%s"' % arg for arg in args]
  81         new_environ = os.environ.copy()
  82         new_environ["RUN_MAIN"] = 'true'
  83         exit_code = os.spawnve(os.P_WAIT, sys.executable, args, new_environ)
  84         if exit_code != 3:
  85             return exit_code
  86
  87 def python_reloader(main_func, args, kwargs):
  88     if os.environ.get("RUN_MAIN") == "true":
  89         thread.start_new_thread(main_func, args, kwargs)
  90         try:
  91             reloader_thread()
  92         except KeyboardInterrupt:
  93             pass
  94     else:
  95         try:
  96             sys.exit(restart_with_reloader())
  97         except KeyboardInterrupt:
  98             pass
  99
 100 def jython_reloader(main_func, args, kwargs):
 101     from _systemrestart import SystemRestart
 102     thread.start_new_thread(main_func, args)
 103     while True:
 104         if code_changed():
 105             raise SystemRestart
 106         time.sleep(1)
 107
 108
 109 def main(main_func, args=None, kwargs=None):
 110     if args is None:
 111         args = ()
 112     if kwargs is None:
 113         kwargs = {}
 114     if sys.platform.startswith('java'):
 115         reloader = jython_reloader
 116     else:
 117         reloader = python_reloader
 118     reloader(main_func, args, kwargs)
 119