Google Compute Engine 上的 Flask - 无法从外部/浏览器访问

Posted 2023-02-25

【中文标题】Google Compute Engine 上的 Flask - 无法从外部/浏览器访问

【英文标题】：Flask on Google Compute Engine - cant reach from outside/browser

【发布时间】：2019-01-25 22:10:00

【问题描述】：

我在我的 Compute Engine 上设置了一个简单的 Flask 服务器，它在 127.0.0.1:5000 内部运行。

如果我 ssh 到该实例并 curl 127.0.0.1:5000 我会看到 hello world 消息，并且 Flask 实例在其日志中显示获取。

但是，如果我通过浏览器使用外部 IP 地址，它会说该站点不存在。

我尝试设置多个差异防火墙，指向 0.0.0.0/0 或 127.0.0.1/0 并包括 tcp:5000 和 udp，或者只是 tcp，或者只是说允许所有端口。

没有任何作用。

我确实尝试运行 netstat -plant，它说端口 5000 已连接到 python3（这是我的 Flask 实例），但该端口已关闭。

更新：

得到它的工作，但会添加更多的日志记录/输出，以防其他人也遇到这个问题。

me@instance-1:~$ nmap 1.2.3.4 Starting Nmap 7.40 ( https://nmap.org ) at 2018-08-19 15:30 UTC Nmap scan report for 4.3.2.1.bc.googleusercontent.com (1.2.3.4) Host is up (0.0016s latency). Not shown: 995 filtered ports PORT STATE SERVICE 22/tcp open ssh 80/tcp closed http 443/tcp closed https 3389/tcp closed ms-wbt-server 5000/tcp closed upnp

me@instance-1:~$ netstat -plant (Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.) Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 127.0.0.1:5000 0.0.0.0:* LISTEN 29414/python3 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN - tcp 0 1 10.142.0.2:22 118.24.87.43:51760 LAST_ACK - tcp 0 0 10.142.0.2:41788 169.254.169.254:80 CLOSE_WAIT - tcp 0 0 10.142.0.2:41796 169.254.169.254:80 ESTABLISHED - tcp 0 0 127.0.0.1:55258 127.0.0.1:5000 TIME_WAIT - tcp 0 0 10.142.0.2:41794 169.254.169.254:80 ESTABLISHED - tcp 0 0 10.142.0.2:22 74.125.73.96:47952 ESTABLISHED - tcp 0 816 10.142.0.2:22 74.125.73.36:51834 ESTABLISHED - tcp 0 0 10.142.0.2:41792 169.254.169.254:80 ESTABLISHED - tcp6 0 0 :::22 :::* LISTEN -

然后我使用重新启动烧瓶

flask run --host=0.0.0.0 --port=5000

现在……

me@instance-1:~$ netstat -plant (Not all processes could be identified, non-owned process info will not be shown, you would have to be root to see it all.) Active Internet connections (servers and established) Proto Recv-Q Send-Q Local Address Foreign Address State PID/Program name tcp 0 0 0.0.0.0:5000 0.0.0.0:* LISTEN 31365/python3 tcp 0 0 0.0.0.0:22 0.0.0.0:* LISTEN - tcp 0 0 10.142.0.2:45802 169.254.169.254:80 ESTABLISHED - tcp 0 0 127.0.0.1:55258 127.0.0.1:5000 TIME_WAIT - tcp 0 0 10.142.0.2:41794 169.254.169.254:80 CLOSE_WAIT - tcp 0 0 10.142.0.2:45804 169.254.169.254:80 ESTABLISHED - tcp 0 0 10.142.0.2:22 74.125.73.96:47952 ESTABLISHED - tcp 0 0 10.142.0.2:45800 169.254.169.254:80 ESTABLISHED - tcp 0 816 10.142.0.2:22 74.125.73.36:51834 ESTABLISHED - tcp6 0 0 :::22 :::* LISTEN - me@instance-1:~$ nmap 1.3.3.4 Starting Nmap 7.40 ( https://nmap.org ) at 2018-08-19 19:24 UTC Nmap scan report for 4.3.2.1.bc.googleusercontent.com (1.2.3.4) Host is up (0.0012s latency). Not shown: 995 filtered ports PORT STATE SERVICE 22/tcp open ssh 80/tcp closed http 443/tcp closed https 3389/tcp closed ms-wbt-server 5000/tcp open upnp Nmap done: 1 IP address (1 host up) scanned in 4.75 seconds

【参考方案1】：

我假设您使用的是默认运行方法，即提供主机地址为 0.0.0.0，这样就可以解决问题

from flask import Flask

app = Flask(__name__)

@app.route('/')
def index():
    return 'Hi'

if __name__ == '__main__':
    app.run(host='0.0.0.0', port=5000)

这将允许您使用 ip 地址从本地主机访问您的网站。

如果您使用的是烧瓶运行方法，则将其运行为

flask run --host=0.0.0.0 --port=5000