mehdi-mirzaie78 / docker

Docker

SECTION 1 (20 minutes)

• Virtual Macnines VS Docker
• When VM and when Docker?
• Benefits of each one

---

SECTION 2 (40 minutes)

• image and tags
• basic commands: pull images python3.10 & python 3.9 work with them
• containers
• work around some commands and features
• Dockerfile -> create image of a simple django project
• .dockerignore
• etc(Push to registry, load, save) *

Dockerfile

FROM python:3.11
LABEL Maintainer="[e-mail]"
LABEL Owner="Maktab93"
LABEL version="v1.1"
WORKDIR /app
COPY requirements.txt .
RUN pip install -U pip
RUN pip install -r requirements.txt
COPY . .
EXPOSE 8000
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]

---

Break (15 minutes)

---

SECTION 3 - Postgres and Django (45 minutes)

• run postgres container without volume and with a volume
• connect local django server to postgres container using port-forwarding
  • what happens if i had 15 containers and I wanted to connect them together -> we talk about it in docker-compose section.
• connecting the container shell
• importance of volumes and consistency of data

Django Settings for postgres database

DATABASES = {
    'default': {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "posgres",
        "USER": "postgres",
        "PASSWORD": "postgres",
        "HOST": "localhost",
        "PORT": "5432"
    }
}

Start a Postgres Container

docker run --name db -e POSTGRES_PASSWORD=postgres -e POSTGRES_USER=postgres -d  postgres

With port-forwording

-p 5432:5432 postgres

With docker volume OR With connecting local place to container

-v volume_name:container_path

-v /tmp:/var/lib/postgresql/data

Connecting to postgres container

docker exec -it db bash
psql -U postgres

Full command for postgres image:

docker run --name basic-postgres --rm -e POSTGRES_USER=postgres -e POSTGRES_PASSWORD=4y7sV96vA9wv46VR -e PGDATA=/var/lib/postgresql/data/pgdata -v /tmp:/var/lib/postgresql/data -p 5432:5432 -it postgres:14.1-alpine

---

SECTION 4 - docker-compose & network & volume (1 hour)

• Simple Django Project with docker
• postgres container + app container
• connecting these to once without .env file
• the other time using .env file for both container and django project (because it is a sensetive information)

Django Settings for postgres database

DATABASES = {
    'default': {
        "ENGINE": "django.db.backends.postgresql",
        "NAME": "posgres",
        "USER": "postgres",
        "PASSWORD": "postgres",
        "HOST": "db",
        "PORT": "5432"
    }
}

Dockerfile

FROM python:3.11
LABEL Maintainer="[e-mail]"
LABEL Owner="Maktab93"
LABEL version="v1.1"
WORKDIR /app
COPY requirements.txt .
RUN pip install -U pip
RUN pip install -r requirements.txt
COPY . .
EXPOSE 8000
CMD ["python", "manage.py", "runserver", "0.0.0.0:8000"]

docker-compose.yml

services:
  db:
    container_name: postgres
    image: postgres:latest
    environment:
      - POSTGRES_DB=postgres
      - POSTGRES_USER=postgres
      - POSTGRES_PASSWORD=postgres
    networks:
      - main_net
    ports:
      - "5432:5432"
    restart: on-failure
    volumes:
      - postgres_data:/var/lib/postgresql/postgres_data
    
  app:
    build: .
    command: sh -c "python manage.py migrate && python manage.py runserver 0.0.0.0:8000"
    container_name: app
    volumes: 
      - .:/app
    depends_on:
      - db
    expose:
      - "8000"
    networks:
      - main_net
    ports:
      - "8000:8000"
    restart: on-failure

volumes:
  postgres_data:

networks:
  main_net: