Practice of deploying web applications written in Python with Docker

import os
from flask import Flask 
import socket 
from gevent import pywsgi
app = Flask(__name__) 

@app.route('/') 
def hello(): 
    html = "<h3>Hello {name}!</h3>" \
    "<b>Hostname:</b> {hostname}<br/>" 
    return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname()) 

if __name__ == "__main__": 
    server = pywsgi.WSGIServer(('0.0.0.0', 12345), app)
    server.serve_forever()

pip freeze >requirements.txt

Flask==2.0.1
gevent==21.8.0
greenlet==1.1.1
itsdangerous==2.0.1
Jinja2==3.0.1
MarkupSafe==2.0.1
Werkzeug==2.0.1
zope.event==4.5.0
zope.interface==5.4.0

# Use the official Python development image as the base image FROM python:3.8-slim 

# Change the working directory to /app 
WORKDIR /app 

#Copy all the contents in the current directory to /app ADD . /app

# Use pip to install the dependencies required by this application # RUN pip install --trusted-host pypi.python.org -r requirements.txt 
RUN pip install --trusted-host https://pypi.tuna.tsinghua.edu.cn/simple -r requirements.txt 
# Domestic sources are faster# Allow external access to the container's port 12345 EXPOSE 12345 

# Set environment variable ENV NAME World 

# Set the container process to: python app.py, that is: the startup command of this Python application CMD ["python", "app.py"]
# CMD implicitly includes ENTRYPOINT, /bin/sh -c

docker build -t helloworld .

[+] Building 17.4s (10/10) FINISHED
 => [internal] load build definition from Dockerfile 0.1s
 => => transferring dockerfile: 757B 0.0s
 => [internal] load .dockerignore 0.1s
 => =>transferring context: 2B 0.0s
 => [internal] load metadata for docker.io/library/python:3.8-slim 2.9s
 => [auth] library/python:pull token for registry-1.docker.io 0.0s
 => [1/4] FROM docker.io/library/python:3.8-slim@sha256:4dd66d1ccaddaa0587851cb92b365bf3090dccb41393c6f8b 0.0s
 => [internal] load build context 0.1s
 => => transferring context: 813B 0.0s
 => CACHED [2/4] WORKDIR /app 0.0s
 => [3/4] ADD ./app 0.1s
 => [4/4] RUN pip install --trusted-host https://pypi.tuna.tsinghua.edu.cn/simple -r requirements.txt 13.6s
 => exporting to image 0.6s
 => => exporting layers 0.6s
 => => writing image sha256:390d32b9f7a20ccd347361bd31450807d3e63d052e334865cf8460968ffceff4 0.0s
 => => naming to docker.io/library/helloworld 0.0s

Use 'docker scan' to run Snyk tests against images to find vulnerabilities and learn how to fix them

(k8s)PC:/mnt/d/gitcode/k8s$ docker image ls
REPOSITORY TAG IMAGE ID CREATED SIZE
helloworld latest 390d32b9f7a2 About a minute ago 169MB

docker run -p 4000:12345 helloworld

(base) $ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
f6e051d1af6b helloworld "python app.py" 2 minutes ago Up 2 minutes 0.0.0.0:4000->12345/tcp, :::4000->12345/tcp upbeat_elion

curl http://localhost:4000
# <h3>Hello World!</h3><b>Hostname:</b> dc1c1343e366<br/>

docker tag helloworld kobe24o/helloworld:v0

docker push kobe24o/helloworld:v0

(k8s) $ docker push kobe24o/helloworld:v0
The push refers to repository [docker.io/kobe24o/helloworld]
931022d457d6: Pushing [=================> ] 16.07MB/47.27MB
c76dc68917fc: Pushed
047ca6dfe9ab: Pushed
d82f4c466b47: Mounted from library/python
5aa75f4e55e7: Mounted from library/python
74d6903a940b: Mounted from library/python
2f9c2b8e82bd: Mounted from library/python
ba5a5fe43301: Mounted from library/python

(base) $ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS
           NAMES
dd3bf057cb09 helloworld "python app.py" 7 seconds ago Up 5 seconds 0.0.0.0:4000->12345/tcp, :::4000->12345/tcp compassionate_carver

(base) $ docker exec -it dd3bf057cb09 /bin/sh
# pwd
/app
# touch newfile.txt
# ls
Dockerfile app.py newfile.txt requirements.txt
# exit

(base) $ docker commit dd3bf057cb09 kobe24o/helloworld:v1
sha256:ca8880f84040f9bdd7ef13763b9c64f8bd4a513a74bc2b095be06aae5b60268a

docker inspect --format '{{ .State.Pid}}' dd3bf057cb09
1763
# View the process ID PID of the running container 

root:/# ls -l /proc/{PID}/ns/
total 0
lrwxrwxrwx 1 root root 0 Sep 14 11:15 cgroup -> 'cgroup:[4026531835]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 ipc -> 'ipc:[4026532220]'
lrwxrwxrwx 1 root root 0 Sep 14 09:49 mnt -> 'mnt:[4026532218]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 net -> 'net:[4026531992]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 pid -> 'pid:[4026532221]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 pid_for_children -> 'pid:[4026532221]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 user -> 'user:[4026531837]'
lrwxrwxrwx 1 root root 0 Sep 14 11:15 uts -> 'uts:[4026532219]'

(base) $ docker push kobe24o/helloworld:v1
The push refers to repository [docker.io/kobe24o/helloworld]
dfee38b42dbb: Pushed
931022d457d6: Layer already exists
c76dc68917fc: Layer already exists
047ca6dfe9ab: Layer already exists
d82f4c466b47: Layer already exists
5aa75f4e55e7: Layer already exists
74d6903a940b: Layer already exists
2f9c2b8e82bd: Layer already exists
ba5a5fe43301: Layer already exists
v1: digest: sha256:7af7ff571ea9fd70d48abeaa2b38a1ed1c1a4e5a933b722d82af25d3e889f84e size: 2206