DOCKER.md

Docker

Best practices used

• Use .dockerignore files

• Use multi-stage builds

  • There are several stages:
    • Install system dependencies
    • Install project-specific packages
    • Build an app
    • Run the server

• Don't install unnecessary packages

  • I didn't include a text editor in a database image.

• Leverage build cache

  • to cache layers, we need to copy the most volatile files into the image as late as possible
  • also described here

• Dockerfile instructions

  • In both apps' Dockerfiles:
    • used the base images via FROM
    • introduced env variables via ENV
    • exposed ports via EXPOSE
    • created an ENTRYPOINT to set the default command in exec form
    • And left its args in the overridable CMD

• Followed 12-factor-app guide

  • Each server reads from its dotenv files (.env)

• Used heredocs in Dockerfiles to ease reading multiline commands

• Used hadolint to lint the Docker files

Available Commands and Tasks

See the docs