eventlet.pathcer.monkey_patch

gistfile1.py

# from eventlet/pathcer.py

def monkey_patch(**on):
    """Globally patches certain system modules to be greenthread-friendly.

    The keyword arguments afford some control over which modules are patched.
    If no keyword arguments are supplied, all possible modules are patched.
    If keywords are set to True, only the specified modules are patched.  E.g.,
    ``monkey_patch(socket=True, select=True)`` patches only the select and 
    socket modules.  Most arguments patch the single module of the same name 
    (os, time, select).  The exceptions are socket, which also patches the ssl 
    module if present; and thread, which patches thread, threading, and Queue.

    It's safe to call monkey_patch multiple times.
    """    
    accepted_args = set(('os', 'select', 'socket', 
                         'thread', 'time', 'psycopg', 'MySQLdb'))
    default_on = on.pop("all",None)
    for k in on.iterkeys():
        if k not in accepted_args:
            raise TypeError("monkey_patch() got an unexpected "\
                                "keyword argument %r" % k)
    if default_on is None:
        default_on = not (True in on.values())
    for modname in accepted_args:
        if modname == 'MySQLdb':
            # MySQLdb is only on when explicitly patched for the moment
            on.setdefault(modname, False)
        on.setdefault(modname, default_on)
        
    modules_to_patch = []
    patched_thread = False
    if on['os'] and not already_patched.get('os'):
        modules_to_patch += _green_os_modules()
        already_patched['os'] = True
    if on['select'] and not already_patched.get('select'):
        modules_to_patch += _green_select_modules()
        already_patched['select'] = True
    if on['socket'] and not already_patched.get('socket'):
        modules_to_patch += _green_socket_modules()
        already_patched['socket'] = True
    if on['thread'] and not already_patched.get('thread'):
        patched_thread = True
        modules_to_patch += _green_thread_modules()
        already_patched['thread'] = True
    if on['time'] and not already_patched.get('time'):
        modules_to_patch += _green_time_modules()
        already_patched['time'] = True
    if on.get('MySQLdb') and not already_patched.get('MySQLdb'):
        modules_to_patch += _green_MySQLdb()
        already_patched['MySQLdb'] = True
    if on['psycopg'] and not already_patched.get('psycopg'):
        try:
            from eventlet.support import psycopg2_patcher
            psycopg2_patcher.make_psycopg_green()
            already_patched['psycopg'] = True
        except ImportError:
            # note that if we get an importerror from trying to
            # monkeypatch psycopg, we will continually retry it
            # whenever monkey_patch is called; this should not be a
            # performance problem but it allows is_monkey_patched to
            # tell us whether or not we succeeded
            pass

    imp.acquire_lock()
    try:
        for name, mod in modules_to_patch:
            orig_mod = sys.modules.get(name)
            if orig_mod is None:
                orig_mod = __import__(name)
            for attr_name in mod.__patched__:
                patched_attr = getattr(mod, attr_name, None)
                if patched_attr is not None:
                    setattr(orig_mod, attr_name, patched_attr)

        # hacks ahead; this is necessary to prevent a KeyError on program exit
        if patched_thread:
            _patch_main_thread(sys.modules['threading'])
    finally:
        imp.release_lock()