[PYTHON] Create a web service with Docker + Flask

Create a web service with Docker + Flask

Introduction

We will introduce it using the sample application (feedback-api).

`Although it is an article on Mac environment, the procedure is the same for Windows environment. Please read and try the environment-dependent part. ``

Purpose

After reading this article to the end, you will be able to:

Execution environment

Source code

I think that understanding will deepen if you read while actually following the implementation contents and source code. Please use it by all means.

GitHub

Related articles

• Docker

0. Development environment

tree.sh

/
│── config/
├── app/
└── Dockerfiles/
     ├── app/
     │   ├── Dockerfile
     │   ├── docker-compose.yml
     │   └── entrypoint.sh
     ├── docker_compose_up.sh
     └── docker_run.sh

1. Install docker

command_line.sh

~$ brew install docker
~$ brew cask install docker

2. Common definition

2-1. Dockerfile definition

FROM python:3.7

RUN mkdir /code
WORKDIR /code

ADD entrypoint.sh /code/entrypoint.sh
ADD app/ /code

RUN pip install --upgrade pip --no-cache-dir
RUN pip install -r requirements.txt --no-cache-dir

EXPOSE 5000
ENV PYTHONPATH "${PYTHONPATH}:/code/"
ENV FLASK_APP "/code/run.py"
CMD ["/code/entrypoint.sh"]

2-2. Entry point definition

Dockerfiles/app/entrypoint.sh

#!/bin/sh

sleep 5

flask db init
flask db migrate
flask db upgrade

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

3. When connecting to RDB on localhost

docker(flask) <-> localhost(postgres)

3-0. Prerequisites

Keep postgres start on localhost.

3-1. sh definition

Dockerfiles/docker_run.sh

#!/bin/sh

docker stop $(docker ps -q)
docker rm $(docker ps -q -a)
# docker rmi $(docker images -q) -f

rsync -av --exclude=app/tests* app Dockerfiles/app

docker build -t feedback-api Dockerfiles/app
docker run -it -p 5000:5000 feedback-api:latest

3-2. Sh execution

command_line.sh

Dockerfiles/docker_run.sh

4. When connecting to the RDB of the container

docker(flask) <-> docker(postgres)

4-0. Prerequisites

Keep postgres on localhost stop.

4-1. sh definition

Dockerfiles/docker_compose_up.sh

#!/bin/sh

docker stop $(docker ps -q)
docker rm $(docker ps -q -a)
# docker rmi $(docker images -q) -f

rsync -av --exclude=app/tests* app Dockerfiles/app

docker-compose -f Dockerfiles/app/docker-compose.yml up --build

4-2. yml definition

Dockerfiles/app/docker-compose.yml

version: '3'
services:
  docker_postgres:
    image: postgres:11.5
    ports:
      - 5432:5432
    environment:
      POSTGRES_USER: postgres
      POSTGRES_PASSWORD: postgres
      POSTGRES_DB: feedback
      POSTGRES_INITDB_ARGS: --encoding=UTF-8

  app:
    build: .
    depends_on:
      - docker_postgres
    ports:
      - 5000:5000
    environment:
      ENV_CONFIG: docker
      SQLALCHEMY_POOL_SIZE: 5
      SQLALCHEMY_MAX_OVERFLOW: 10
      SQLALCHEMY_POOL_TIMEOUT: 30

4-3. Sh execution

command_line.sh

Dockerfiles/docker_compose_up.sh