#nix-darwin

When my ESP32 detects a pulled-down voltage at

GPIO4

, this means that the water level has reached the upper limit in my condensation collection container. This is because i have

GND

ran out to the bottom of the bin, and

GPIO4

is set to

INPUT_PULLUP

.

GPIO3

is set to the same but I do not turn on the pump for this pin. Instead, i use that pin to know when to turn off the pump once the pump has been turned on at the upper limit.

When the

ESP32

sends a request to my local hue bridge to activate the smartplug where I have my dremel pump plugged in, and nothing happens, I need to figure out what HTTP request is actually going out. I use requestbin for this. The publicly available service became sporadically available many years back, but you can still run it via docker. Once its running, it gives me a URL i can substitute for the Hue bridge API endpoint, I ca inspect

The command for this is

docker run --rm -it -p 8000:8000 weshigbee/requestbin

That's just a little too unwieldy to remember, so I'd like to make a permanent utility to run it. While writing this, i realize i could have just aliased it and added it to my zsh config inside my home-manager config under

programs.zsh.shellAliases

However, in my early-morning sleepy haze, I opted to create a solution as arguably over-engineered as it may be forgivingly considered succinctly practical. I have

\~/.local/bin

in my

home.sessionPath

. I have slowly been evolving how I manage these utilities for the last few months. The primary difference between files in

\~/.local/bin

and a shell alias is that files in that directory can be shell scripts. For example

\~/.local/bin/update

used to be a shell alias bound to

NIXPKGS\_ALLOW\_INSECURE=1 darwin-rebuild switch --flake "$HOME/.nixpkgs#$(hostname)" --impure

Today, it's a shell script:

cd ~/.nixpkgs # capture local binary utilities for file in `find ~/.local/bin/ -maxdepth 1 -type f`; do mv $file ~/.nixpkgs/user-specific/sdevol/.local/bin/ done git add user-specific/sdevol/.local/bin # capture the espanso configuration cp -R ~/.config/espanso/* ~/.nixpkgs/user-specific/sdevol/.config/espanso/ git add ~/.nixpkgs/user-specific/sdevol/.config/espanso NIXPKGS_ALLOW_INSECURE=1 darwin-rebuild switch --flake "$HOME/.nixpkgs#$(hostname)" --impure

My nix configuration lives in

\~/.nixpkgs

. Notice that we are moving files from

\~/.local/bin

into the nix repo under

\~/.nixpkgs/user-specific/sdevol/.local/bin

. As you might have began to suspect, there's some plumbing inside

\~/.nixpkgs/user-specific/sdevol/home.nix

that connects some more dots.

# let localBinDir = ./.local/bin; localBinFiles = builtins.attrNames (builtins.readDir localBinDir); mkLocalBin = name: { source = ./.local/bin/${name}; recursive = true; }; in rec { manual.manpages.enable = false; home = { username = "tastypre"; file = builtins.listToAttrs (map (name: { name = ".local/bin/${name}"; value = mkLocalBin name; }) localBinFiles) // { ".config/zed/settings.json" = { source = ./zed.settings.json; recursive = true; }; ".config/espanso" = { source = config.lib.file.mkOutOfStoreSymlink .config/espanso; recursive = true; };

So, when I type

update

.

Any non-symlinks are moved into the nix configuration

My nix configuration is rebuilt, within which the nix configuration iterates through all files in its local directory

user-specific/sdevol/.local/bin

A

home.file.\*

reference is generated with a symlink configuration for each.

This sequence thus replaces non-symlinked files in

\~/.local/bin

with symlinks to version-controlled references to the same. Therefore, once i have decided i want to make a permanent command for

docker run --rm -it -p 8000:8000 weshigbee/requestbin

. All I need to do is , press up on my keyboard so that the docker command is at the prompt and modify the command to read.

echo docker run --rm -it -p 8000:8000 weshigbee/requestbin > \~/.local/bin/requestbin then

ls ~/.local/bin` reads

ls -l ~/.local/bin  ✔  26ms   18.1.0  10:24:11  lrwxr-xr-x - tastypre 16 Aug 09:49 readlinks -> /nix/store/m2aiz6gszyk3i4hbqn93dpwpsi6f805p-home-manager-files/.local/bin/readlinks .rw-r--r-- 54 tastypre 16 Aug 10:24 requestbin lrwxr-xr-x - tastypre 16 Aug 09:49 screensnap -> /nix/store/m2aiz6gszyk3i4hbqn93dpwpsi6f805p-home-manager-files/.local/bin/screensnap lrwxr-xr-x - tastypre 16 Aug 09:49 tastyspace -> /nix/store/m2aiz6gszyk3i4hbqn93dpwpsi6f805p-home-manager-files/.local/bin/tastyspace lrwxr-xr-x - tastypre 16 Aug 09:49 update -> /nix/store/m2aiz6gszyk3i4hbqn93dpwpsi6f805p-home-manager-files/.local/bin/update

Now, i just run

update

Now,

requestbin

is in

\~/.local/bin/requestbin

but it has been swapped out with a symlink to my nix config's manifested version of the script.

lrwxr-xr-x - tastypre 16 Aug 10:26 requestbin -> /nix/store/vgrdrcnjyhykkx1xq29kg6g2jhbqg0hx-home-manager-files/.local/bin/requestbin