Docker Compose file explained - mnhmilu/poc-kubernets GitHub Wiki

It seems like you provided the beginning of a docker-compose.yml file for a Docker Compose setup. The provided YAML file includes the configuration for the app service, but it's missing the rest of the settings and services.

A typical docker-compose.yml file consists of one or more services, each representing a Docker container that makes up your application. Here's an example of how you can continue the docker-compose.yml file:

version: '3'

services:
  app:
    build:
      context: .
    ports:
      - "8000:8000"
    environment:
      - ENV_VARIABLE=value  # Replace with any environment variables required by your app
    command: uvicorn app.main:app --host 0.0.0.0 --port 8000
    depends_on:
      - db

  db:
    image: postgres:latest
    environment:
      - POSTGRES_USER=user
      - POSTGRES_PASSWORD=password
      - POSTGRES_DB=dbname
    volumes:
      - pgdata:/var/lib/postgresql/data

volumes:
  pgdata:

Explanation of the docker-compose.yml content:

1. app Service:

   • build: Specifies that the Docker image for the app service should be built using the Dockerfile located in the current directory (context: .).
   • ports: Maps port 8000 of the host machine to port 8000 of the app service container. This allows you to access the FastAPI application at http://localhost:8000.
   • environment: Allows you to define environment variables that your FastAPI application might need. Replace ENV_VARIABLE=value with the required environment variables and their values.
   • command: Specifies the command to be executed when the app service container starts. This command starts the FastAPI application using Uvicorn with the appropriate host and port.
   • depends_on: Indicates that the app service depends on the db service. This ensures that the PostgreSQL database container (db) is started before the app service.

2. db Service:

   • image: Specifies the base image for the PostgreSQL database. It will pull the latest version of the PostgreSQL image from Docker Hub.
   • environment: Sets environment variables for the PostgreSQL container, including the database username, password, and name.
   • volumes: Mounts a volume named pgdata to persist the database data between container restarts.

The example assumes that you have defined the rest of the docker-compose.yml file with other services (if any) and appropriate configurations for your application.

To use this docker-compose.yml file, create a new file named docker-compose.yml, copy the content, and paste it into the file. Then, make any necessary modifications to suit your specific project (e.g., replace environment variables, database settings, etc.). Finally, run the docker-compose up command in the same directory as the docker-compose.yml file to start the application and database containers.