andrea crotti於 2012年7月19日星期四UTC+8下午6時15分11秒寫道： > We need to be able to reload code on a live system. This live system > has a daemon process always running but it runs many subprocesses with > multiprocessing, and the subprocesses might have a short life... > > Now I found a way to reload the code successfully, as you can see from > this testcase: > > > def func(): > from . import a > print(a.ret()) > > > class TestMultiProc(unittest.TestCase): > def setUp(self): > open(path.join(cur_dir, 'a.py'), 'w').write(old_a) > > def tearDown(self): > remove(path.join(cur_dir, 'a.py')) > > def test_reloading(self): > """Starting a new process gives a different result > """ > p1 = Process(target=func) > p2 = Process(target=func) > p1.start() > res = p1.join() > open(path.join(cur_dir, 'a.py'), 'w').write(new_a) > remove(path.join(cur_dir, 'a.pyc')) > > p2.start() > res = p2.join() > > > As long as I import the code in the function and make sure to remove the > "pyc" files everything seems to work.. > Are there any possible problems which I'm not seeing in this approach or > it's safe? > > Any other better ways otherwise?
If a byte code interpreter is embedded in the executable, then the program can obtain or reload code objects in the run time. In C/C++, unless one can swap some DLL safely or spawn in another process with new executables obtained from other places, or a script interpreter is embedded, otherwise it's not easy for an instance in C/C++ to get new methods dynamically. or -- http://mail.python.org/mailman/listinfo/python-list
