Optional Docker services and dependencies

Like many, docker and and compose have become my go-to tool to create software that can be conveniently deployed to production with a limited amount of headache. However, many tasks, and sometimes whole services, pertain only to the development side of the workflow, and need to stay there. Moreover, some tasks, such as time-consuming provisioning tasks, are only on-demand one-offs. They shouldn’t run at all most of the time, but they should slot into the dependency graph correctly when needed. tl;dr: I realised that docker compose supports profiles, which allows services to be enabled conditionally, along with the depends_on.[].required option, to ignore them when they are disabled. Profiles are also useful to package actions and triggers to run on demand, so they are not started by default. We can start with a simple setup where our long-running main service depends on an init service to perform preliminary steps. This can be setup with depends_on the compose.yaml. services: main:…