python – Flask：后台线程看到一个非空队列为空

组件

>具有thread-safe queue的Flask应用程序.
> GET调用返回队列大小.
> POST调用向队列中添加一个元素.
>后台线程打印队列大小

问题

当应用程序是从shell使用python tester.py时,我得到预期的结果：

2014-06-07 14:20:50.677995 Queue size is: 0
127.0.0.1 - - [07/Jun/2014 14:20:51] "POST /addMessage/X HTTP/1.1" 200 -
2014-06-07 14:20:51.679277 Queue size is: 1
2014-06-07 14:20:52.680425 Queue size is: 1
2014-06-07 14:20:53.681566 Queue size is: 1
2014-06-07 14:20:54.682708 Queue size is: 1
127.0.0.1 - - [07/Jun/2014 14:20:55] "POST /addMessage/Y HTTP/1.1" 200 -
2014-06-07 14:20:55.687755 Queue size is: 2
2014-06-07 14:20:56.688867 Queue size is: 2

但是,当使用uwsgi执行应用程序时,我在日志中得到以下内容：

2014-06-07 14:17:42.056863 Queue size is: 0
2014-06-07 14:17:43.057952 Queue size is: 0
[pid: 9879|app: 0|req: 6/6] 127.0.0.1 () {24 vars in 280 bytes} [Sat Jun  7 14:17:43 2014] POST /addMessage/X => generated 16 bytes in 0 msecs (HTTP/1.1 200) 2 headers in 71 bytes (1 switches on core 0)
2014-06-07 14:17:44.059037 Queue size is: 0
2014-06-07 14:17:45.060118 Queue size is: 0
[pid: 9879|app: 0|req: 7/7] 127.0.0.1 () {24 vars in 280 bytes} [Sat Jun  7 14:17:45 2014] POST /addMessage/X => generated 16 bytes in 0 msecs (HTTP/1.1 200) 2 headers in 71 bytes (1 switches on core 0)
2014-06-07 14:17:46.061205 Queue size is: 0
2014-06-07 14:17:47.062286 Queue size is: 0

当在uwsgi下运行时,后台线程看不到与应用程序相同的队列.这是为什么？我怎么能让这两个线程看同一个Queue对象？

更新

>即使将其作为Python脚本执行,我也看到不一致的行为：有时它不会记录消息(使用app.logger),我只能看到打印.这意味着线程正在运行,但它不能与app.logger做任何事情.

uwsgi .ini配置

[uwsgi]
http-socket    = :9002
plugin         = python
wsgi-file      = /home/ubuntu/threadtest-uwsgi.py
enable-threads = true
workers        = 1
chdir          = /home/ubuntu/thread-tester/thread_tester

码

from flask import Flask,jsonify
import Queue
from threading import Thread
import time
import datetime
import logging
import sys

logging.basicConfig(stream=sys.stderr,format='%(asctime)s %(levelname)s - %(message)s')

app = Flask(__name__)
messages = Queue.Queue()

def print_queue_size():
    while True:
        app.logger.debug("%s Queue size is: %d" % (datetime.datetime.now(),messages.qsize()))
        time.sleep(1)

t = Thread(target=print_queue_size,args=())
t.setDaemon(True)
t.start()

@app.route("/queueSize",methods=["GET"])
def get_queue_size():
    return jsonify({"qsize": messages.qsize()}),200

@app.route("/addMessage/<message>",methods=["POST"])
def add_message_to_queue(message):
    messages.put(message)
    return jsonify({"qsize": messages.qsize()}),200

if __name__ == "__main__":
    app.run(port=6000)