worker 中的 Python uwsgi 线程

Question

uwsgi 新手，当我运行以下代码时

from time import sleep
import threading
import os
import sys


i = 0


def daemon():
    print("pid ", os.getpid())
    global i
    while True:
        i += 1
        print("pid ", os.getpid(), i)
        sleep(3)


th = threading.Thread(target=daemon, args=())
th.start()

print("application pid ", os.getpid())


def application(environ, start_response):
    start_response('200 OK', [('Content-Type', 'text/html')])
    return [str(i).encode()]


def atexit(*args):
    import uwsgi
    print('At exit called ', uwsgi.worker_id(), os.getpid())
    sys.exit(1)


try:
    import uwsgi
    uwsgi.atexit = atexit
except ImportError:
    pass

使用命令

uwsgi --http :9090 --wsgi-file  wsgi.py  --enable-threads --processes 2

我得到输出

*** WARNING: you are running uWSGI without its master process manager ***
your processes number limit is 1418
your memory page size is 4096 bytes
detected max file descriptor number: 256
lock engine: OSX spinlocks
thunder lock: disabled (you can enable it with --thunder-lock)
uWSGI http bound on :9090 fd 4
spawned uWSGI http 1 (pid: 37671)
uwsgi socket 0 bound to TCP address 127.0.0.1:62946 (port auto-assigned) fd 3
Python version: 3.7.4 
python threads support enabled
your server socket listen backlog is limited to 100 connections
your mercy for graceful operations on workers is 60 seconds
mapped 145776 bytes (142 KB) for 2 cores
*** Operational MODE: preforking ***
pid  37670
application pid  37670
pid  37670 1
WSGI app 0 (mountpoint='') ready in 0 seconds on interpreter 0x7fd29af02010 pid: 37670 (default app)
*** uWSGI is running in multiple interpreter mode ***
spawned uWSGI worker 1 (pid: 37670, cores: 1)
spawned uWSGI worker 2 (pid: 37672, cores: 1)

pid  37670 2
pid  37670 3
pid  37670 4

我得到两个工作进程(37670 和 37672)。但是我正在创建的线程 th = threading.Thread(target=daemon, args=())仅在第一个工作进程 (37670) 中运行，但不在 37672 中运行...

题:

我期待另一个线程也在第二个工作进程中运行，但显然情况并非如此。它在内部如何运作？

我如何为每个工作进程和主进程分别创建线程(在这个例子中，我没有运行主进程)

Answer 1

这似乎是因为预 fork 。 uwsgi通过加载应用程序一次(因此只有一个解释器)然后根据所需的进程 fork 来工作。
如果我们使用惰性应用程序，

uwsgi --http :9090 --wsgi-file  wsgi.py  --enable-threads --processes 2 --lazy-apps

这会为每个进程加载一个应用程序，并且该线程在两个工作进程中运行。更多信息 here .

输出

*** uWSGI is running in multiple interpreter mode ***
spawned uWSGI worker 1 (pid: 14983, cores: 1)
spawned uWSGI worker 2 (pid: 14985, cores: 1)
pid 14983
pid 14985
Application pid 14983
Application pid 14985
WSGI app 0 (mountpoint='') ready in 0 seconds on interpreter 0x55e8d5282bb0 pid: 14985 (default app)
WSGI app 0 (mountpoint='') ready in 0 seconds on interpreter 0x55e8d5282bb0 pid: 14983 (default app)
pid 14985 1
pid 14983 1
pid 14985 2
pid 14983 2
pid 14985 3
pid 14983 3

您可以使用 uwsgi 中的 --threads 选项为每个进程创建多个线程

--processes 2 --threads 2

这为每个进程创建了 2 个线程。