Hi. I have an app in a flake that uses another app (like a database). It doesn't need it for building, but it should be there for run-time. Is there a way I can bundle the two together?

In reply to @rob.sliwi:matrix.org
What's the context?
NixOS has modules that make this possible.
Otherwise you could include the run-time deps in the devShell and use them when you need it?
Or make an app that runs both, the app and the deps as well?

I thought of maybe making a flake that depends on two flakes for the two apps that I want to bundle together. I was wondering if there was any official flake-y way of having a user install a set of related apps in their profile.

some packages have a hook like this or similar

preBuild = ''
  export XDG_CACHE_HOME="$(mktemp -d)"
'';

I have a flake with a devShells.default that uses inputsFrom to create a development environment for a package. If I use nix develop it drops me into a shell with a correct phase functions (buildPhase, etc.). However, if I use nix develop --build I get unexpected errors about no makefiles and if I use nix develop --command bash -c buildPhase bash complains about no such command buildPhase.

What do I need to do in my devShells.default so that either nix develop --build or nix develop --command bash -c buildPhase works? Thanks!