Local Development

While Defang encourages using a single compose file, there are times when it is more convenient to use different files for different environments. For example, if some services should be configured differently locally: maybe you want to mount your working directory as a volume for live-reloading, or you want to build a different container image for local development. Another reason may be that you have some local services, like an auth mock or a local webhook listener that you don't want to deploy to the cloud.

compose.local.yaml

In these cases, Defang recommends creating a file like compose.local.yaml which extends service definitions from your primary compose.yaml file.

For example,

# compose.yaml
services:
  app:
    build:
      context: .
      dockerfile: Dockerfile

# compose.local.yaml
services:
  app:
    extends:
      file: compose.yaml
      service: app
    build:
      context: .
      dockerfile: local.Dockerfile
    volumes:
      - .:/web
  local_service:
    image: myservice:latest

This configuration can then be launched locally with

docker compose -f compose.local.yaml

And the primary compose file can be deployed to the cloud with

defang compose up

See our blog post on Dev Containers and Codespaces for more information on getting set up in those environments.