python Gunicorn

1. 简介

Gunicorn(Green Unicorn)是给Unix用的WSGI HTTP 服务器，它与不同的web框架是非常兼容的、易安装、轻、速度快。

2. 示例代码1

def app(environ, start_response):
    data = b"Hello World\n"
    start_response("200 OK", [
        ("Content-Type", "test/plain"),
        ("Content-Length", str(len(data)))
    ])
    return iter([data])

启动

gunicorn -w 4 myapp:app

起来后显示

[2016-12-12 00:20:12 +0000] [11755] [INFO] Starting gunicorn 19.6.0
[2016-12-12 00:20:12 +0000] [11755] [INFO] Listening at: http://127.0.0.1:8000 (11755)
[2016-12-12 00:20:12 +0000] [11755] [INFO] Using worker: sync
[2016-12-12 00:20:12 +0000] [11760] [INFO] Booting worker with pid: 11760
[2016-12-12 00:20:12 +0000] [11761] [INFO] Booting worker with pid: 11761
[2016-12-12 00:20:12 +0000] [11762] [INFO] Booting worker with pid: 11762
[2016-12-12 00:20:12 +0000] [11763] [INFO] Booting worker with pid: 11763

此时，调用http://127.0.0.1:8000

$curl http://127.0.0.1:8000
Hello World

参数说明

-w  处理HTTP请求的worker进程数，以下两种启动方式等价

gunicorn -w 4 myapp:app
gunicorn --workers=4 myapp:app

参考：

  -w INT, --workers INT
                        The number of worker processes for handling requests.

问题：为何调用 http://ip:8000不行呢， 这个是什么请求呢？

默认有-b参数，参考

  -b ADDRESS, --bind ADDRESS
                        The socket to bind. [['127.0.0.1:8000']]

以下方式启动就可以用ip的方式启动了

sudo gunicorn -w 2 -b 0.0.0.0:4000 myapp:app

3. 示例代码2

之前简单的flask方法

from flask import Flask
app = Flask(__name__)

@app.route('/hello.world')
def check():
    return 'hello world!'


if __name__ == '__main__':
    app.run()

启动

$sudo gunicorn -b 0.0.0.0:300  -w 4 myapp3:app
[2016-12-18 19:19:51 +0000] [21005] [INFO] Starting gunicorn 19.6.0
[2016-12-18 19:19:51 +0000] [21005] [INFO] Listening at: http://0.0.0.0:300 (21005)
[2016-12-18 19:19:51 +0000] [21005] [INFO] Using worker: sync
[2016-12-18 19:19:51 +0000] [21010] [INFO] Booting worker with pid: 21010
[2016-12-18 19:19:51 +0000] [21011] [INFO] Booting worker with pid: 21011
[2016-12-18 19:19:51 +0000] [21014] [INFO] Booting worker with pid: 21014
[2016-12-18 19:19:51 +0000] [21017] [INFO] Booting worker with pid: 21017

测试

$curl localhost:300/hello.world
hello world!

4. 启动异常：[ERROR] Connection in use: ('127.0.0.1', 8000)

原因之一是之前启动的进程没有杀死。

注：ctrl+z 是挂起进程，但没有终止。ctrl+c是终止进程。

如果使用了ctrl+z再回到进程中可使用fg命令，这样可以用ctrl+c来关闭进程