Defining services is punishingly complicated

[t184256]

Not sure whether to file that against disnix or dysnomia. Also I should warn in advance that I'm only one week into the Nix world and clearly not Nix-minded enough yet.

If one wants to use Disnix to run a process that requires even a single command line argument, e.g. iperf -s, one must jump through so many hoops it's not even funny.

If I understood correctly, launching it without the -s would've required just iperf = { name = "iperf"; pkg = pkgs.iperf; type = "process"; };. But in order to add that little -s one must: 0. Specify type = "wrapper";.

1. Write a wrapper for it (your way seems to be: create a directory, write a wrapper, reuse a templating Makefile, compile (!) it)
2. Override a derivation and build it with the wrapper baked in (I can't even grasp how at the moment).

Am I wrong? Can the process be streamlined somehow? At the moment it's easier to overrideAttrs on the package and patch the sources to imply that '-s' than to make a wrapper.

Ideally I'd like to specify type = "process"; args = ["-s"]; for this trivial operation and something like

baseDir = "/var/lib/service";
type = modularWrapper {
  collectGarbage = ''
    rm -r $baseDir
  '';
  systemdUnit = ''
    [Unit]
    After=disnix.service

    [Install]
    WantedBy=dysnomia.target

    [Service]
    Environment=PATH=${dysnomia.systemdPath}
    Type=simple;
  '';
};

for more complex ones. Is this possible?