Containers Web-Servers

How to Dockerize and Run Python Script Connecting to Mysql in Apache

In this guide, we will use CGI (Common Gateway Interface) Scripts to serve a simple python crud API. We will be dockerizing our code and using docker compose to test the application with mariadb.

# The code

This is the simple crud python code that we are trying to run in docker with apache using cgi

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#!/usr/bin/python3

import json
import os
import pymysql

DB_USER = os.getenv("DB_USER") or "tasksapi"
DB_PSWD = os.getenv("DB_PSWD") or "tasksapi"
DB_NAME = os.getenv("DB_NAME") or "tasksapi"
DB_HOST = os.getenv("DB_HOST") or "mariadb"

db = pymysql.connect(
    host=DB_HOST,
    user=DB_USER,
    password=DB_PSWD,
    database=DB_NAME,
    cursorclass=pymysql.cursors.DictCursor,
)
cursor = db.cursor()


# Create a new task
def create_task(title):
    try:
        cursor.execute("INSERT INTO tasks (title) VALUES (%s)", title)
        db.commit()
        cursor.execute("SELECT MAX(id) AS id FROM tasks")
        row = cursor.fetchone()
        resp = get_task(row["id"])
        return (resp[0], 201)
    except Exception as e:
        return (str(e), 500)


# Get all tasks
def get_tasks():
    try:
        cursor.execute(
            "SELECT id, title, date_format(created, '%Y-%m-%d %H:%i') as created FROM tasks"
        )
        return (cursor.fetchall(), 200)
    except Exception as e:
        return (str(e), 500)


# Get an individual task
def get_task(id):
    try:
        cursor.execute(
            "SELECT id, title, date_format(created, '%Y-%m-%d %H:%i') as created \
                FROM tasks WHERE id="
            + str(id)
        )
        row = cursor.fetchone()
        return (row if row is not None else "", 200 if row is not None else 404)
    except Exception as e:
        return ("", 404)


# Update an existing task
def update_task(id, title):
    try:
        cursor.execute("UPDATE tasks SET title=%s WHERE id=%s", (title, id))
        db.commit()
        return get_task(id)
    except Exception as e:
        return (str(e), 500)


# Delete an existing task
def delete_task(id):
    try:
        resp = get_task(id)
        if resp[1] == 200:
            cursor.execute("DELETE FROM tasks WHERE id=%s", id)
            db.commit()
            return ("", 200)
        else:
            return resp
    except Exception as e:
        return (str(e), 500)


# Returns the HTTP request method
def get_method():
    return os.getenv("REQUEST_METHOD") or "GET"


# Returns the query string
def get_query_string():
    query_string = os.getenv("QUERY_STRING") or ""
    return query_string.replace("%20", " ").replace("%2F", "/").replace("+", " ")


# Returns the task ID if set in the request query string
def get_task_id():
    query_string = get_query_string()
    qs_parts = query_string.split("/")
    return qs_parts[0] if qs_parts[0].isnumeric() else None


# Returns the task title from the query string if set
def get_task_title():
    title = None
    query_string = get_query_string()
    if query_string != "":
        qs_parts = query_string.split("/")
        title = qs_parts[1] if len(qs_parts) > 1 else qs_parts[0]
        title = None if title.isnumeric() else title
    return title


# Returns True if title is valid, False otherwise
def title_is_valid(title):
    return (
        True
        if isinstance(title, str) and len(title) >= 6 and len(title) <= 255
        else False
    )


# Returns a status code method
def get_status_msg(code):
    msg = "OK"
    msg = "Created" if code == 201 else msg
    msg = "Not Found" if code == 404 else msg
    msg = "Bad Request" if code == 400 else msg
    msg = "Internal Server Error" if code == 500 else msg
    return msg

method = get_method()
id = get_task_id()
title = get_task_title()

if method == "GET" and not id is None:
    resp = get_task(id)
elif method == "GET":
    resp = get_tasks()
elif method == "DELETE":
    resp = delete_task(id)
elif not title_is_valid(title):
    resp = ("", 400)
elif method == "POST":
    resp = create_task(title)
elif method == "PUT":
    resp = update_task(id, title)

print("Status: %d %s" % (resp[1], get_status_msg(resp[1])))
print("Content-type: application/json\n")
print(json.dumps(resp[0]))

If you would want a simple script instead to test that this works, use this

Save this as test-db.py

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#!/usr/bin/python3
import os
import pymysql

# Database connection parameters - update as needed
DB_USER = os.getenv("DB_USER") or "root"
DB_PSWD = os.getenv("DB_PSWD") or None
DB_HOST = os.getenv("DB_HOST") or "localhost"

db = pymysql.connect(
    host=DB_HOST,
    user=DB_USER,
    password=DB_PSWD,
    database="mysql",
    cursorclass=pymysql.cursors.DictCursor,
)
cursor = db.cursor()
cursor.execute("SHOW DATABASES")

print("Content-type: text/html\n")
print("Setup Successful")

# The Dockerfile

We will use this Dockerfile to package our application so we can serve it anywhere.

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FROM httpd:2.4-alpine
WORKDIR /usr/local/apache2/cgi-bin/
RUN apk update && \
    apk add python3 python3-dev py3-pip gcc g++ libffi-dev && \
    rm /var/cache/apk/*
COPY requirements.txt .
RUN pip3 install -U pip --break-system-packages && \
    pip3 install -r requirements.txt --break-system-packages
COPY tasks-api.py .
RUN chmod +x tasks-api.py
CMD httpd-foreground -c "LoadModule cgid_module modules/mod_cgid.so"

Here, we are using httpd:2.4-alpine as our base image then adding python dependencies to make the environment work for our script.

This is the contents of the requirements.txt file

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pymysql
cryptography

# The Docker compose logic to put together the code

This is my docker compose compose.yml file

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version: "3.9"

services:
  tasksapi:
    image: ektowett/tasksapi:latest
    working_dir: /usr/src/app
    build:
      dockerfile: Dockerfile
      context: .
    ports:
      - 8080:80
    depends_on:
      - mariadb
    environment:
      - DB_USER=tasksapi
      - DB_PSWD=tasksapi
      - DB_NAME=tasksapi
      - DB_HOST=mariadb
    networks:
      - tasksapi_net

  mariadb:
    image: mariadb:11
    ports:
      - 3306:3306
    volumes:
      - tasksapi_db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=tasksapi
      - MYSQL_DATABASE=tasksapi
      - MYSQL_USER=tasksapi
      - MYSQL_PASSWORD=tasksapi
    networks:
      - tasksapi_net

volumes:
  tasksapi_db:

networks:
  tasksapi_net:

To run the above, use

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docker-compose up -d

This will build our image and download mariadb image if it doesn’t exist.

# Creating the database

Exec into the db instance

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docker-compose exec mariadb bash

Then login to db

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root@bd7b8ceb1225:/# mariadb -u tasksapi -ptasksapi
Welcome to the MariaDB monitor.  Commands end with ; or \g.
Your MariaDB connection id is 4
Server version: 11.3.2-MariaDB-1:11.3.2+maria~ubu2204 mariadb.org binary distribution

Copyright (c) 2000, 2018, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [(none)]>

Create table

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MariaDB [(none)]> show databases;
+--------------------+
| Database           |
+--------------------+
| information_schema |
| tasksapi           |
+--------------------+
2 rows in set (0.001 sec)

MariaDB [(none)]> use tasksapi;
Database changed
MariaDB [tasksapi]> CREATE TABLE tasks (
    ->   id INT NOT NULL AUTO_INCREMENT,
    ->   title VARCHAR(255) NOT NULL,
    ->   created TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    ->   PRIMARY KEY (id),
    ->   INDEX(created)
    -> );
Query OK, 0 rows affected (0.012 sec)

MariaDB [tasksapi]> show tables;
+--------------------+
| Tables_in_tasksapi |
+--------------------+
| tasks              |
+--------------------+
1 row in set (0.001 sec)

# Testing our code

Get all tasks

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$ curl http://127.0.0.1:8080/cgi-bin/tasks-api.py

[]

Add Task

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$ curl -X POST -s -D - http://127.0.0.1:8080/cgi-bin/tasks-api.py\?First+Task

HTTP/1.1 201 Created
Date: Wed, 13 Mar 2024 16:05:51 GMT
Server: Apache/2.4.58 (Unix)
Transfer-Encoding: chunked
Content-Type: application/json

{"id": 1, "title": "First Task", "created": "2024-03-13 16:05"}

$ curl -X POST -s -D - http://127.0.0.1:8080/cgi-bin/tasks-api.py?Second+Task

HTTP/1.1 201 Created
Date: Wed, 13 Mar 2024 16:06:19 GMT
Server: Apache/2.4.58 (Unix)
Transfer-Encoding: chunked
Content-Type: application/json

{"id": 2, "title": "Second Task", "created": "2024-03-13 16:06"}

Get Tasks

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$ curl http://127.0.0.1:8080/cgi-bin/tasks-api.py

[{"id": 1, "title": "First Task", "created": "2024-03-13 16:05"}, {"id": 2, "title": "Second Task", "created": "2024-03-13 16:06"}]

Get task

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$ curl http://127.0.0.1:8080/cgi-bin/tasks-api.py\?1

{"id": 1, "title": "First Task", "created": "2024-03-13 16:05"}
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