More than one process can be defined and run (simultaneously) using one of the Procfile based runners.

Basically, provide the same functionality as https://github.com/srid/proc-flake

As an example, use it in https://github.com/EmaApps/ema-template

Replace these two options with a single option, exec that uses types.oneOf that accepts either of the types of the former options.

I recently started to use mission-control, and noticed that the banner is always printed when entering the devshell - normally good behaviour, but I also happen to run the dev shell during CI runs, and printing the banner for pretty much every step made my build logs much more verbose than they need to be, and a bit annoying to glance through. See here for an example - just expand any step beyond bootstrap to see what I mean.

I could work it around by setting a custom banner that checks the $CI environment variable, and does not display the banner if it is set. But that meant replicating the entire banner snippet.

Would it be possible to have an option like mission-control.banner-display-condition? A shell snippet that the default banner uses like ${banner-display-condition} && menu? It'd default to true, but would make it easier for me to override it: mission-control.banner-display-condition = ''[ -z "$CI" ]'';.

I'm happy to open a pull request adding this (possibly with a better option name - I'm not good at naming), if this is something you'd find useful too. I might even be able to name it mission-control.banner.display-condition, while also remaining backwards compatible, so mission-control.banner = ''<some text>''; would still work.

The default command for mission-control is ,. That takes precedence over https://github.com/nix-community/comma usually. But it would be nice if mission-control could detect presence of an existing , in PATH and delegate to it when the given command is unknown.

When description contains backticks:

{
  description = "Foo `bar` qux";
}

we see:

error: builder for '/nix/store/bhr9lfplzh0352yh4n6gnxdbjqbba7wh--.drv' failed with exit code 1;
       last 7 log lines:
       >
       > In /nix/store/lcd5hrlm9vl4l8j15kqazr5xqm0di25p--/bin/, line 10:
       >   echo -e '## Backend';echo;echo '  , backend-ghcid : Compile the given local package using ghcid.
       >                                  ^-- SC2016 (info): Expressions don't expand in single quotes, use double quotes for that.
       >
       > For more information:
       >   https://www.shellcheck.net/wiki/SC2016 -- Expressions don't expand in singl...
       For full logs, run 'nix log /nix/store/bhr9lfplzh0352yh4n6gnxdbjqbba7wh--.drv'.
error: 1 dependencies of derivation '/nix/store/0rj05a1mlisffwyn649j17sri7bhnz3r-ghc-shell-for-packages-0-env.drv' failed to build

Details

If I cd to a sub-directory and run my scripts, $PWD will still return the root path of the flake.

Working on top of https://github.com/wbolster/emacs-direnv - provide a M-x command that allows one to run one of the mission-control commands.

Open questions

• What kind of UX do we provide for long-running processes?
  • Should the process runner be decoupled from emacs?

... so that users can manually wire it to their flake outputs. For example, they can set it to apps.* so as to be able to nix run the scripts without entering the devshell.

This decoupling can also facilitate #24

By default we cd automatically to the project root (as determined by flake-root module) before launching the script. It should be possible to disable this feature via a per-script option.

We need this for defining scripts like ghcid which can take arguments that are relative paths.

If the user does this, the Nix expression should error out, printing a helpful error message.

Use something like https://www.nushell.sh/ instead of bash

Aim for facilitating resolution of #28, #4, #32 and the like.

This,

   fmt = { 
     exec = "${lib.getExe pkgs.nixpkgs-fmt} ./*.nix"; 
     flakeApp = true;
   }; 

... would wire a flake app of the same name, so that nix run .#fmt will work (in addition to nix develop -c , fmt).

Useful in https://github.com/srid/nixos-config for running activation without entering the devShell. Useful for users who do not use direnv, as well.

cc @marijanp

Because of the prerun thing,

In the example nix shell, typing , followed by hitting the TAB should auto-complete the user-configured script names (hello and fmt in the case of the example). This should work on both bash and zsh (inasmuch as macOS uses zsh by default).

The code for this could potentially go here:

For reference, see how purs-nix implements it:
https://github.com/purs-nix/purs-nix/blob/0fae0fd9316a20e2312cfdbcb8135b0e56330e01/purs-nix-command.nix#L254-L271

For a config like,

          fmt = {
            exec = pkgs.treefmt;
            category = "Dev Tools";
          };

mission-control generates , treefmt. But we want it to be , fmt instead.

This should also incidentally fix the conflict with an attrset key being the same as one of the shell tools in PATH.

Test in srid/haskell-template@fb9634b#diff-206b9ce276ab5971a2489d75eb1b12999d4bf3843b7988cbe8d687cfde61dea0R55

Allow sharing mission-control configs among multiple projects.

For example, many Haskell project reuse these scripts. It should be possible to import them one-line rather them duplicating them in every project.

cf. https://matrix.to/#/!gcrYWdPsIUOFpXFDHB:matrix.org/$j3lN4rCpqlbKtHH_pEtGE3n-1iRUGQ1hHlU8RzHCvvU?via=matrix.org&via=nixos.dev&via=gaze.systems

You could do something like this to avoid copying the lock:

      flake = {
        templates.default.path = (inputs.nixpkgs.lib.cleanSourceWith {
          src = ./.;
          filter = path: type: baseNameOf path == "flake.nix";
        }).outPath;
      };