uWSGI + Flask + boto - 线程安全 [英] uWSGI+Flask+boto - thread safety

问题描述

假设我有一个Flask应用程序，由uWSGI使用多个进程提供服务，如：

  uwsgi --socket 127.0.0.1 ：3031  -  file flaskapp.py --callable app --processes 4 
  

我的Flask应用程序是像这样组织：

  / flaskapp 
 app.py 
 / db 
 __init__.py 
 somefile.py 
 somefile2.py 
 ... 
  

我正在使用boto连接到DynamoDB。 __ init __。py 文件是空的，并且每个 somefilexxx.py 文件都是这样开始的：

$ table $ db $ b $ do_stuff_with_table（）：

我不使用应用程序中的线程，我不认为uWSGI使用线程，除非我明确用 - threads 来启用它们。这个设置是否有意义？有没有任何线程问题，我不得不担心urllib（你可能猜测我知道线程没有什么比... ...）？

另外，它会更有意义在 __ init __。py 文件中调用 connect_dynamodb（），只加载 somefile.py files？

解决方案

由于您尚未在uWSGI中启用线程（请参阅 - 启用线程， - 线程）这里没有Python线程正在进行（以Boto或其他方式） / p>

我会推荐使用 - lazy ，这会导致您的应用程序被加载到每个worker post-fork中。那么你可以简单地依靠这种行为，以确保每个工人有适当的连接/池/等。没有共享状态的担忧。

Say I have a Flask application, served by uWSGI using multiple processes, like:

uwsgi --socket 127.0.0.1:3031 --file flaskapp.py --callable app --processes 4

And my Flask app is organized like this:

/flaskapp
    app.py
    /db
        __init__.py
        somefile.py
        somefile2.py
        ...

And I'm using boto to connect to DynamoDB. The __init__.py file is empty, and each somefilexxx.py file begins something like this:

db = boto.connect_dynamodb()
table = db.get_table('table')
def do_stuff_with_table():

I don't use threads in the app, and I don't think uWSGI uses threads unless I explicitly enable them with --threads. Does this setup make sense? Are there any threading issues I have to worry about with urllib (you might guess I know less than nothing about threads...)?

Alternatively, would it make more sense to call connect_dynamodb() in the __init__.py file and only load the tables in the somefile.py files?

解决方案

Since you haven't enabled threads in uWSGI (see: --enable-threads, --threads) there's no Python threading going on here (in Boto or otherwise.)

I would recommend using --lazy, which will cause your app to be loaded in each worker post-fork. Then you can simply rely on that behavior to ensure each worker has the appropriate connections/pools/etc. available without the concerns of shared state.

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