Prepare the execution environment of Python3 with Docker

"Creating a service that edits the usage history of Mobile Suica so that it can be easily used for expense settlement" First of all, we will develop in Python, so create an environment where Python can be executed

Writer's environment

windows PC (Core i7-7600 / 16GB) Edit with VS code It is convenient to include Python and Docker extensions

policy

Since it is developed on a Windows PC, it is troublesome to do it directly. Python execution environment sets up a container with Docker

Preparation

Install ** Docker for Windows ** It is necessary to enable Hyper-V. Also install [** docker-compose **] * [Docker] Install Docker and Docker Compose on Windows 10 Pro 64bit

Create a Dockerfile

I will install various things, so build the image Save the following file as Dockerfile in a suitable directory somewhere

Dockerfile

FROM centos/python-36-centos7:latest
USER root
RUN yum -y install java-1.8.0-openjdk
RUN pip install flask pandas tabula-py uwsgi
WORKDIR /src
ENV PYTHONUNBUFFERED=1

• FROM centos/python-36-centos7:latest --Use this image of Docker Hub as a base
• USER root --Become root
• RUN yum -y install java-1.8.0-openjdk --Install Java required for tabula-py
• RUN pip install flask pandas tabula-py uwsgi --Install the required modules (flask, uwsgi are not needed at this time, will be used later)
• WORKDIR /src --When you enter the container, it will be here
• ENV PYTHONUNBUFFERED=1 -Setting to disable console stdout (standard output) and stderr (standard error output) buffers

Create docker-compose.yml

Since you edit the Python file on Windows and run it on Docker, you need to be able to see the Python file on Windows from the container. This can be specified with "-v" when launching the container, but since Windows is troublesome and I do not want to type the command every time, docker-compose makes one command

docker-compose.yml

version: '3.7'
services:

  testenv:
    build:
      context: ./app
      dockerfile: Dockerfile
    container_name: testenv
    tty: true
    command: /bin/sh -c "while :; do sleep 10; done"
    volumes:
      - ./app/src:/src

volumes:
  temp:

• testenv --You can change it freely
• build --Build a container --context: Dockerfile location --dockerfile: The name of the Dockerfile
• container_name --You can change it freely
• tty: true ――It's magical to keep the container up, but it didn't work ...
• command: /bin/sh -c "while :; do sleep 10; done" -The container stayed up for the first time with this
• volumes: --Mount Windows ./app/src as / src on the container. Now you can see the Python file edited with VS Code from the container as it is

If there is no command: part, the container will drop in an instant When I google, most people solve it with tty: true, but for some reason it is useless in my environment

Place the Dockerfile and docker-compose.yml from earlier like this test.py is a Python file to run

│  docker-compose.yml
│
└─app
    │  Dockerfile
    │
    └─src
            test.py

Launch the container

$ docker-compose.exe up --build -d
Creating network "test_default" with the default driver
Building testenv
Step 1/6 : FROM centos/python-36-centos7:latest
 ---> 90c6a4022ee5
Step 2/6 : USER root
 ---> Using cache
 ---> 03e9f59a6dbc
Step 3/6 : RUN yum -y install java-1.8.0-openjdk
 ---> Using cache
 ---> 463337c7b050
Step 4/6 : RUN pip install flask pandas tabula-py PyPDF2 uwsgi crontab
 ---> Using cache
 ---> 26c28d2b838c
Step 5/6 : WORKDIR /src
 ---> Running in f5ab2a9b405e
Removing intermediate container f5ab2a9b405e
 ---> b998a42b8180
Step 6/6 : ENV PYTHONUNBUFFERED=1
 ---> Running in fd8d783f9e2f
Removing intermediate container fd8d783f9e2f
 ---> e1e0833bc33a

Successfully built e1e0833bc33a
Successfully tagged test_testenv:latest

See if you got up

$ docker ps
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS              PORTS               NAMES
3b7e97ef1fd5        test_testenv        "container-entrypoin…"   4 seconds ago       Up 2 seconds        8080/tcp            testenv

Try to enter the container

$ winpty docker exec -it testenv bash
(app-root) bash-4.2# pwd
/src
(app-root) bash-4.2# ls
test.py
(app-root) bash-4.2# cat test.py
print('Hello, World')
(app-root) bash-4.2# python3 test.py
Hello, World

Now you can finally start writing the code.