Question

我正在尝试将bottle.py作为脚本中的进程运行，但我感到很沮丧，因为它不能像我预期的那样工作。这是我的脚本的假设/缩短表示。我试着添加尽可能多的评论。

magball.py

import serial
from bottle import route, run, template, request
import multiprocessing
import logging
import datetime


#Here are the most important variables which will be used in the entire script
global lastcommand #The last command received from bottle web interface
global status #What is the current status

lastcommand = 'Go Home' #Options: Start Drawing, Go Home, Next Drawing
status = 'home' #Options: home, homing (means going home), drawing

def log_this(level, msg)
    #a special log function based on logging library for debugging
    pass # <- details are not important, it is working fine

now = datetime.datetime.now()
timeString = now.strftime("%Y-%m-%d %H:%M")
info = {'title' : 'MAGBALL', 'time': timeString, 'lastcommand': lastcommand, 'status': status} #These are passed to main.tpl
@route('/', method='GET')
@route('/', method='POST')
def index(): #<- This works fine, passing the info to the template file (main.tpl) in views directory
    global lastcommand #<- Isn't this referring to the global lastcommand declared at the beginning?
    if request.method == 'POST':
        lastcommand = request.forms.get("submit") #<- This works fine and lastcommand changes when the button on the web page is clicked    
        log_this('info', (lastcommand + ' clicked on web interface')) #<- I can see in the logs which button is clicked, so, this should mean 
                                                                      #that lastcommand (supposedly the global one) was changed successfully

    return template('main.tpl', info)

p_bottle = multiprocessing.Process(target=run, kwargs=dict(host='0.0.0.0', port=80, debug='True')) #<- I start bottle as a process because I think I have to
p_bottle.daemon = True

def draw_pattern() #<- This function can easily run for hours which is fine/normal for the purpose
                   #Unless lastcommand is not equal to 'Start Drawing' this should run forever
    global status
    global lastcommand
    status = 'drawing' #<- I think this should also refer to the global lastcommand declared at the beginning
    #Opens a random file from a specific directory, 
    for filename in shuffled_directory:
        #reads the file line by line and feeds it to the serial port
        .
        .
        if lastcommand != 'Start Drawing': #<- This never works! Although I see in the logs that lastcommand was changed by index() function
            log_this('warning', 'Last command changed during line feeding.')
            break

def go_home()
    global status
    status = 'homing' #<- I think this should also refer to the global lastcommand declared at the beginning
    #Send some commands to serial port and after that change the value of status
    .
    .
    status = 'home'

while true: #This is the infinite loop that needs to run forever
    global status #Don't these variables also refer to the global variables declared at the beginning? 
    global lastcommand
    p_bottle.start() #The bottle.py web interface runs successfully
    #The following while, if etc never runs. I think this "while true:" statement never gets notified
    #that the values of lastcommand and/or status has changed
    while lastcommand == 'Start Drawing':   
        if status == 'home':
            draw_pattern()
        if status == 'homing':
            time.sleep(5)
        if status == 'drawing':
            pass
    while lastcommand == 'Next Drawing':
        if status == 'home':
            draw_pattern()
        if status == 'homing':
            time.sleep(5)
        if status == 'drawing':
            go_home()
            draw_pattern()
    while lastcommand == 'Go Home':
        if status == 'home':
            pass
        if status == 'homing':
            pass
        if status == 'drawing':
            go_home()

main.tpl

<!DOCTYPE html>
   <head>
      <title>{{ title }}</title>
   </head>
   <body>
      <h1>Magball Web Interface</h1>
      <h2>The date and time on the server is: {{ time }}</h2>
    <h2>The last command is: {{ lastcommand }}</h2>
    <h2>Status: {{ status }}</h2>
    <form name='magballaction' method='POST'>
    <input type="submit" name="submit" value="Start Drawing">
    <input type="submit" name="submit" value="Go Home">
    <input type="submit" name="submit" value="Next Drawing">
    </form>
   </body>
</html>

以下是发生的事情：
瓶子流程运行正常（网页是可访问的），当我点击网页上的按钮时，我在日志中看到lastcommand的值已被Web界面更改。

然而，最后的无限循环（while true:）永远不会被告知lastcommand的值已被更改。因此，例如，如果status = home和lastcommand已从Web界面更改为“Start Drawing”，则它不会执行draw_pattern()。它什么都不做。

我尝试将所有内容放在def index()行之前的return template('main.tpl', info)函数中，但随后代码会运行，但Web界面会等待代码完成才能启动。由于draw_pattern()会持续数小时，因此return template('main.tpl', info)行几乎无法运行，并且无法访问该网页。

我还尝试将def index()作为普通函数运行，但是当我这样做时，唯一运行的就是web界面（def index()）。

那么，我该怎么做才能通知while循环lastcommand和/或status的值已经改变了呢？

Answer 1

For anyone who is interested I have solved the problem using threading instead of multiprocessing. So instead of using this:

p_bottle = multiprocessing.Process(target=run, kwargs=dict(host='0.0.0.0', port=80, debug='True')) 
p_bottle.daemon = True

I used:

p_bottle = threading.Thread(target=run, kwargs=dict(host='0.0.0.0', port=80, debug='True'))
p_bottle.daemon = True

and now the function in the thread can change the global variable successfully which is instantly picked up by the infinite while true loop. Thanks everyone for suggestions.

如何以无限循环同时运行瓶子？

1 个答案: