修改 CherryPy 的关机程序

Question

所以我有一个封装状态机的cherry py 服务器。在幕后，这个状态机完成了管理进程、线程和缓存的所有繁重工作，而且它是线程安全的。因此，在启动我的樱桃 py 时，我将其附加到应用程序中，并且请求调用 app.state_machine.methods。

在伪代码中我这样做：

from flask_app import app
import cherrypy

#configure app

app.state_machine = State_Machine.start()
try:
    cherrypy.tree.graft(app, "/")
    cherrypy.server.unsubscribe()

    server = cherrypy._cpserver.Server()
    server.socket_host="0.0.0.0"
    server.socket_port = 5001
    server.thread_pool = 10
    server.subscribe()

    cherrypy.engine.start()
    cherrypy.engine.block()
except KeyboardInterrupt:
    logging.getLogger(__name__).warn("Recieved keyboard interrupt")
except Exception:
    logging.getLogger(__name__).exception("Unknown exception from app")
finally:
    logging.getLogger(__name__).info("Entering Finally Block")
    state_machine.shutdown()

这里的意图是键盘中断应该传播到应用程序并调用 state_machine.shutdown，它适用于例如烧瓶开发服务器。

但是，cherrypy 吞下 KeyBoard 中断并等待其子线程关闭，因为它们包含对 app.state_machine 的引用，它们将无限期地死锁，直到调用 app.state_machine.shutdown()。

那么如何修改cherrypy的关闭程序，让它正确调用shutdown呢？

Answer 1

根据 web ninja 的建议，答案是使用插件。

from cherrypy.process import wspbus, plugins

class StateMachinePlugin(plugins.SimplePlugin) :

    def __init__(self, bus, state_machine):
        plugins.SimplePlugin.__init__(self, bus)
        self.state_manager = state_machine

    def start(self):
        self.bus.log("Starting state_machine")
        self.state_machine.run()

    def stop(self):
        self.bus.log("Shutting down state_machine")
        self.state_machine.shutdown()
        self.bus.log("Successfully shut down state_machine")

那就做吧：

from flask_app import app
import cherrypy

#configure app

app.state_machine = State_Machine.start()
try:
    cherrypy.tree.graft(app, "/")
    cherrypy.server.unsubscribe()

    server = cherrypy._cpserver.Server()
    server.socket_host="0.0.0.0"
    server.socket_port = 5001
    server.thread_pool = 10
    server.subscribe()

 ###########################Added This line####################
 StateMachinePlugin(cherrypy.engine, app.state_machine).subscribe()
 #####################End Additions##########################

    cherrypy.engine.start()
    cherrypy.engine.block()
except KeyboardInterrupt:
     logging.getLogger(__name__).warn("Recieved keyboard interrupt")
except Exception:
     logging.getLogger(__name__).exception("Unknown exception from app")
finally:
    logging.getLogger(__name__).info("Entering Finally Block")
    state_machine.shutdown()