Add background processes

[JanLikar]

Use devenv up -d to run honcho with nohup.

devenv down and devenv logs are also included and are analog to their docker-compose counterparts.

[JanLikar]

This is first and foremost a PoC, so feel free to voice any concerns you might have, I'm more than happy to address them :)

[domenkozar]

I'm still not sure about this one.

Could you explain what kind of workflow do you have that requires this interface?

[JanLikar]

I often do not need to see application logs while working on the app, so I find it kinda annoying that I need to keep one terminal running just to keep the app running.

[shyim]

I would like to call that also in Gitpod to have one shell.

devenv up -d
devenv shell

and let the user work in the shell and don't have to care about the running services

[domenkozar]

We need to figure how how this interacts with different process backends. Probably each needs to return a pid?

[JanLikar]

I guess so, yes

[thenonameguy]

I recommend creating a prototype using https://github.com/NixOS/nixpkgs/blob/e66309ddcce8fc316b9addeabd11bf2187fa2eb9/pkgs/tools/system/daemonize/default.nix.
This works by wrapping arbitrary programs and turns them into daemon processes.
Should be what we need without relying on the programs to do this themselves.

[thenonameguy]

Started discussion about upstreaming this feature to process-compose so we don't need the above comment:
F1bonacc1/process-compose#35

This way not only the honcho implementation could fulfill the new interface.

[Nebucatnetzer]

Another use case is bootstrapping the project.
E.g. I start Postgres and Django in the background and then I run some commands to run migrations and insert fixtures.
Afterwards I open the URL for the dev server in the browser.
The dev then can start developing and if he needs to reattach to the log view.
I'm currently doing this with overmind.

[domenkozar]

This is now implemented in #745