That’s the Janitor, an on-demand developer environment service for OSS projects. It uses Docker to allow lots of dev envs to be cheaply colocated on powerful bare-metal servers and new environments to be launched very quickly. It’s mostly being developed by Mozilla employees because getting a Firefox developer box set up is hard and compiling it requires monstrous amounts of computer, but it also just added support for Discourse.
With Janitor, developers can get started with a Discourse developer environment by logging into a website and clicking a button. They can also start as many of them as they want.
This should help new contributors, new plugin developers, and non-techie theme designers, because they can skip the UAC/admin prompts, BIOS settings (if you’re using vagrant), and command line. Using the Janitor literally just involves visiting a web page and clicking buttons within it; you cannot mess up your computer, so getting started with it is safe. And if you mess up a container, you can delete it and start again.
This is especially important for designers, who should never be required to set up a local dev environment.
This can help testers, because you can spawn as many dev environments with slightly different configurations as you want.
This can provide a fallback, if you drop your dev laptop in the toilet and are still waiting for the new one to ship.
Supporting a project basically means writing a Dockerfile to initialize an image. In Discourse’s case, we install dependencies like Ruby and PostgreSQL, clone the repo, and run the database migrations. Since the initialized database and cloned GitHub repo are baked into the image, creating your own Discourse development container doesn’t even require GitHub to be up.
The base image used by all the Janitor project images (
janx/ubuntu-dev) also contains stuff that runs in your container that Janitor needs to work right, particularly a copy of the Cloud9 SDK.
Also, you have root access to the container. So go nuts.
Janitor is not a free service for hosting production instances of Discourse; not only does its firewall/proxy set up make that very impractical, it’s also not allowed. Blatant abuse like attacking Twitter, mining Bitcoin, or trying to break out of a dev container and gain access to the host system is also not allowed.