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A Simple REST Flask APP with MariaDB Container

In this tutorial, you will learn how to build a Flask web application and implement the app with database(MariaDB). using postman to test basic REST APIs(HTTP methods: GET, POST, DELETE).

Flask로 Web App을 개발을 하고 데이터베이스와 연동을 하는 방법을 알아본다. CURL을 사용 하여 기본적인 REST API(HTTP methods: GET, POST, DELETE)를 테스트 해본다.

Time to Complete: 1-2 hours

Tutorial Prereqs:

Architecture

docker-flask-mariadb

1. Create a container test network

docker network create test-net

test-net is newly created docker network for this tutorial (other than bridge as the default network)

2. Provision a DB container

Start predefined mariadb container

docker run -p 3306:3306 --name my-mariadb --net test-net -d cloudacode/simple-mariadb:latest

dockerfile of the cloudacode/mariadb: simple-mariadb-container

Note

If you want to setup the database by yourself, please follow below guideline.

(Optional) Start a mariadb instance from scratch

Deploy new MariaDB container

docker run -p 3306:3306 --name my-mariadb --net test-net \
 -e MYSQL_ROOT_PASSWORD=mysecret -e MYSQL_DATABASE=cloud_user \
 -d mariadb:latest

Note

mariadb official repo: https://hub.docker.com/_/mariadb

Initalize the database

connect to db container and database

docker exec -it my-mariadb /bin/bash

If you can see root@b51599196adf:/# in your terminal, it means you are in the container.

login the database via mysql client and initialize the database

mysql -uroot -pmysecret

MariaDB [(none)]> use cloud_user;
Database changed
MariaDB [cloud_user]>
MariaDB [cloud_user]> CREATE TABLE IF NOT EXISTS `cloud_user` (
    `user_id` bigint NOT NULL AUTO_INCREMENT,
    `user_name` varchar(45) DEFAULT NULL,
    `user_email` varchar(45) DEFAULT NULL,
    `user_bio` varchar(255) DEFAULT NULL,
    PRIMARY KEY (`user_id`)
    ) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8 ;

Query OK, 0 rows affected, 1 warning (0.001 sec)

MariaDB [cloud_user]> select * from cloud_user;
Empty set (0.001 sec)

MariaDB [cloud_user]> INSERT INTO `cloud_user` (
    `user_id`,`user_name`,`user_email`, `user_bio`)
    values
    (1,'kc chang','cloudacode@gmail.com', 'mento');

Query OK, 1 row affected (0.001 sec)

MariaDB [cloud_user]>
MariaDB [cloud_user]> select * from cloud_user;
+---------+-----------+----------------------+----------+
| user_id | user_name | user_email           | user_bio |
+---------+-----------+----------------------+----------+
|       1 | kc chang  | cloudacode@gmail.com | mento    |
+---------+-----------+----------------------+----------+
1 row in set (0.000 sec)

3. Build the Flask app

to run the flask app in your local environment, you should build the flask app first.

source code: cloudacode/coolstuff.git

git clone https://github.com/cloudacode/coolstuff.git
cd flask-example/simple-flask-app
docker build -t cloudacode/simple-flask-app:latest .

Note

you can change the cloudacode to your dockerhub repo name

4. Run the Flask app

Run the flask app on your localhost or dev machine

docker run -p 8888:5000 --net test-net \
 -e DB_USER=root -e DB_PASSWORD=mysecret -e DB_NAME=cloud_user -e DB_HOST=simple-mariadb \
 cloudacode/simple-flask-app:latest

OR

docker run -p 8888:5000 --net test-net \
 --env-file ./env.list cloudacode/simple-flask-app:latest

Note

If you are using your own password or database name, you need to replace the vaule in the env.list file

5. Test API request

get date from the server. you can also use the web browser to get the date

curl localhost:8888/user

review the output. here is the expected output message

[
  {
    "user_bio": "mento",
    "user_email": "cloudacode@gmail.com",
    "user_id": 1,
    "user_name": "kc chang"
  }
]

post Json data to the server

curl --header "Content-Type: application/json" \
--request POST \
--data '{"bio": "test user", "email": "test1@cloudacode.com", "name": "test1"}' \
http://localhost:8888/add

get the user list again from the server

curl localhost:8888/user

6. Docker Compose

Install Docker Compose: link

version: "2"
services:
  simple-mariadb:
    image: cloudacode/simple-mariadb:latest
    ports:
      - "3306:3306"
  simple-flask-app:
    links:
      - simple-mariadb
    image: cloudacode/simple-flask-app:latest
    ports:
      - "8888:5000"
    environment:
      - DB_USER=root
      - DB_PASSWORD=mysecret
      - DB_NAME=cloud_user
      - DB_HOST=simple-mariadb

docker-compose.yaml

Run docker compose to up all containers

docker-compose up -d

🎉 Congratulations, you have completed Flask, MariaDB integration tutorial