How can I use CircleCI for multi-stage Docker builds?

How can I use CircleCI for multi-stage Docker builds?

You can set up multi-stage Docker builds in CircleCI by defining your build process in the .circleci/config.yml file. This allows you to optimize your Docker images by separating the build environment from the runtime environment.

Can you provide an example of a config.yml for this?

Sure! Here's a simple example:

version: 2.1
jobs:
  build:
    docker:
      - image: docker:latest
    steps:
      - checkout
      - setup_remote_docker:
          version: 20.10.7
          docker_layer_caching: true
      - run:
          name: Build Docker Image
          command: |
            docker build --target builder -t myapp:builder .
            docker build --target production -t myapp:latest .
workflows:
  version: 2
  build:
    jobs:
      - build

What are the benefits of using multi-stage builds?

Multi-stage builds help reduce the size of your final Docker image by allowing you to copy only the necessary artifacts from the build stage. This results in faster deployment times and improved security.

Are there any limitations I should be aware of?

Yes, one limitation is that multi-stage builds can increase build times if not managed properly, as each stage requires its own context. Additionally, debugging can be more complex due to the separation of stages.