docker-compose.yml

# Specifies the version of the Docker Compose file format. NOTE: This command is obsolete in newer versions of Docker Compose.
version: '3.8'

# Declares the project name for the Docker Compose application.
name: SOSMIT

# Defines the services that will be part of the Docker Compose application.
services:
    # The name of the PostgreSQL database service. We can call it anything we like.
    db:
        # Tells Docker to use the official PostgreSQL image from Docker Hub.
        # We're using version 16 of PostgreSQL, based on Alpine Linux (which is lightweight).
        image: postgres:16-alpine
    
        # This ensures that the database service is always restarted if it stops unexpectedly.
        restart: always

        # The initial configuration for the PostgreSQL  database.
        # IMPORTANT: In a real porduction, passwords should be managed with Docker secrets or other secure methods, NOT hardcoded at all.
        environment:
            POSTGRES_USER: sosmit_admin
            POSTGRES_PASSWORD: admin123
            POSTGRES_DB: sosmit_db
        
        # This maps the PostgreSQL port 5432 on the host machine to the same port in the container.
        # This allows us to connect to the database from outside the container, specifically the Go app (for this specific project).
        ports:
            - '5433:5432'

        # To ensure data persistence, we mount a volume to the container.
        # This means that the data stored in the database will be saved in a directory on the host machine.
        # This tells Docker to create a named volume called 'db_data' and mount it to the PostgreSQL data directory (/var/lib/postgresql/data).
        volumes:
            - db_data:/var/lib/postgresql/data
    backend:
        build:
            context: .
            dockerfile: Dockerfile
            target: production
        env_file:
            - .env
        environment:
            DB_HOST: db
            DB_PORT: 5432
            DB_USER: sosmit_admin
            DB_PASSWORD: admin123
            DB_NAME: sosmit_db
            FRONTEND_URL: ${FRONTEND_URL}
            BACKEND_URL: ${BACKEND_URL}
            SENDGRID_API_KEY: ${SENDGRID_API_KEY}
            SENDER_EMAIL: ${SENDER_EMAIL}
        depends_on:
            - db
        ports:
            - "8080:8080"
        volumes:
            - ./uploads:/app/uploads
    
# This top-level key defines the volumes that will be used by the services.
# It allows Docker to manage persistent data storage.
# The data in this volume will persist on your hard drive even if the container is removed or downed.
volumes:
    db_data: