python 看门狗模块在 redhat 服务器下无法与 django/mod_wsgi 一起使用

python watchdog module doesn't work with django/mod_wsgi under redhat server

我们在redhat服务器的apache2下使用django(1.7.5)和mod_wsgi，并尝试使用watchdog来监控文件。

在本地使用python manager.py runserver命令可以正常工作，而当我将它部署到产品环境时，在wsgi模式下没有触发事件

# wsgi.py
from django.core.wsgi import get_wsgi_application
application = get_wsgi_application()

LOGGER.debug("Starting to watch for config file changes.")
fw = FileWatcher()

# filewatcher
path = settings.PROJECT_ROOT
filename = 'config.json'
class ConfigHandler(FileSystemEventHandler):
    def on_modified(self, event):
        if not event.is_directory and event.src_path.endswith(filename):
            LOGGER.debug("The config has changed!, Reloading")

class FileWatcher(object):

    _instance = None
    _watching = False

    def __new__(cls, *args, **kwargs):
        if not cls._instance:
            LOGGER.debug("Creating new FileWatcher")
            cls._instance = super(FileWatcher, cls).__new__(cls, *args, **kwargs)

            cls.start_watching()

        return cls._instance

    @classmethod
    def start_watching(cls):
        if not cls._watching:
            LOGGER.debug("Starting to monitor the file: %s",
                        os.path.join(path, filename))
            event_handler = ConfigHandler()
            observer = Observer()
            observer.schedule(event_handler, path=path, recursive=False)
            observer.start()

            cls._watching = True

找到路由原因，默认的 Observer (inotify.InotifyObserver) 在具有旧 linux 内核的旧 redhat 服务器中不起作用

在http://pythonhosted.org/watchdog/api.html#module-watchdog.observers

中说明

inotify.InotifyObserver Linux 2.6.13+   inotify(7) based observer
polling.PollingObserver Any fallback implementation

所以我把它改成了通用的

    from watchdog.observers.polling import PollingObserver
    # http://pythonhosted.org/watchdog/api.html#module-watchdog.observers
    observer = PollingObserver()

python 看门狗模块在 redhat 服务器下无法与 django/mod_wsgi 一起使用

python watchdog module doesn't work with django/mod_wsgi under redhat server

python

django

mod-wsgi

python-2.7