docker - Flask应用程序Docker Nginx

Question

我构建了2个包含Flask应用程序(Web容器)的Docker镜像，以及另一个包含Nginx作为负载均衡器的镜像(nginx容器)。

使用docker-compose up and scale命令:

docker-compose up --scale web=2

结果:

Starting dockerflaskloadb_web_1 ... done
Creating dockerflaskloadb_web_2 ... done
Starting dockerflaskloadb_nginx_1 ... done
Attaching to dockerflaskloadb_web_1, dockerflaskloadb_web_2, dockerflaskloadb_nginx_1
web_1    | [2018-08-22 11:27:20 +0000] [1] [INFO] Starting gunicorn 19.6.0
web_1    | [2018-08-22 11:27:20 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1)
web_1    | [2018-08-22 11:27:20 +0000] [1] [INFO] Using worker: sync
web_1    | [2018-08-22 11:27:20 +0000] [8] [INFO] Booting worker with pid: 8
web_2    | [2018-08-22 11:27:21 +0000] [1] [INFO] Starting gunicorn 19.6.0
web_2    | [2018-08-22 11:27:21 +0000] [1] [INFO] Listening at: http://0.0.0.0:8000 (1)
web_2    | [2018-08-22 11:27:21 +0000] [1] [INFO] Using worker: sync
web_2    | [2018-08-22 11:27:21 +0000] [8] [INFO] Booting worker with pid: 8

这是我在Flask应用程序中通过一些获取请求得到的:

nginx_1  |  [22/Aug/2018:11:33:31 +0000] "GET /home HTTP/1.1" 200 5640 "http://192.168.99.100/about" "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36" "-" -172.22.0.4
nginx_1  |  [22/Aug/2018:11:33:33 +0000] "GET /home HTTP/1.1" 200 5640 "http://192.168.99.100/home" "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36" "-" -172.22.0.4
nginx_1  |  [22/Aug/2018:11:33:33 +0000] "GET /about HTTP/1.1" 200 3195 "http://192.168.99.100/home" "Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36" "-" -172.22.0.4

该应用程序运行正常，但我想知道每个请求将使用哪个容器(web1或web2)。

有什么方法可以用来在我的 flask 应用程序中显示容器ID？
谢谢

Answer 1

默认情况下，容器的主机名是容器ID。所以像:

import os
id = os.environ['HOSTNAME']

要么

import socket
print(socket.gethostname())