Initial commit

compose.dev.yml

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+services:
+  # Service name for our PostgreSQL database
+  db:
+    # We use a specific version of PostgreSQL for stability.
+    # The 'alpine' tag means it's a smaller image size.
+    image: postgres:16-alpine
+
+    # This ensures the database container restarts automatically if it crashes or the server reboots.
+    restart: always
+
+    # Environment variables are loaded from the .env file.
+    # These are used by the PostgreSQL image to create the user and database on first run.
+    environment:
+      POSTGRES_USER: ${DB_USER}
+      POSTGRES_PASSWORD: ${DB_PASSWORD}
+      POSTGRES_DB: ${DB_NAME}
+
+    # Port mapping: <HOST_PORT>:<CONTAINER_PORT>
+    # - We expose the internal container port 5432 (PostgreSQL's default)
+    # - to our custom port ${DB_PORT} (5433 from our .env) on our local machine.
+    ports:
+      - '${DB_PORT}:5432'
+
+    # Volumes are essential to persist data.
+    # - We create a named volume 'postgres_data'.
+    # - All database files inside the container (/var/lib/postgresql/data) are stored in this volume.
+    # - This means your data is safe even if you remove the container with 'docker-compose down'.
+    volumes:
+      - postgres_data:/var/lib/postgresql/data
+
+    # A healthcheck to ensure the database is ready to accept connections
+    # before other services (if any) might try to connect.
+    healthcheck:
+      test: ['CMD-SHELL', 'pg_isready -U ${DB_USER} -d ${DB_NAME}']
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+# Top-level volumes definition. This is where Docker manages the named volume.
+volumes:
+  postgres_data: