tvl-depot/ops/nixos/irccat.nix
Vincent Ambo cbfcf14301 feat(ops/irccat): Add a NixOS module for launching irccat
This module configures irccat by creating a JSON configuration file
from a user-supplied Nix struct (this is not checked for correctness),
and merging it recursively with secrets from
`/etc/secrets/irccat.json` at service launch time.

This way we get the ability to configure (most) options declaratively
via Nix, while providing the secrets outside of Nix.

Side note: We need to figure out a secrets distribution mechanism.

Tested: Wrote a dummy config in whitby/default.nix locally and checked
that this builds, but I have not actually run the service yet. I
expect that some minor tweaks will end up being necessary.

Change-Id: I02a2e8dc40a7f8417fd77afcf8a12ac3df117988
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2074
Tested-by: BuildkiteCI
Reviewed-by: lukegb <lukegb@tvl.fyi>
Reviewed-by: glittershark <grfn@gws.fyi>
2020-11-08 18:38:08 +00:00

49 lines
1.4 KiB
Nix

{ config, lib, pkgs, ... }:
let
cfg = config.services.depot.irccat;
description = "irccat - forward messages to IRC";
# irccat expects to read its configuration from the *current
# directory*, and its configuration contains secrets.
#
# To make this work we construct the JSON configuration file and
# then recursively merge it with an on-disk secret using jq on
# service launch.
configJson = pkgs.writeText "irccat.json" (builtins.toJSON cfg.config);
configMerge = pkgs.writeShellScript "merge-irccat-config" ''
if [ ! -f "/etc/secrets/irccat.json" ]; then
echo "irccat secrets file is missing"
exit 1
fi
# jq's * is the recursive merge operator
${pkgs.jq}/bin/jq -s '.[0] * .[1]' ${configJson} /etc/secrets/irccat.json \
> /var/lib/irccat/irccat.json
'';
in {
options.services.depot.irccat = {
enable = lib.mkEnableOption description;
config = lib.mkOption {
type = lib.types.attrs; # varying value types
description = "Configuration structure (unchecked!)";
};
};
config = lib.mkIf cfg.enable {
systemd.services.irccat = {
inherit description;
preStart = "${configMerge}";
script = "${config.depot.third_party.irccat}/bin/irccat";
wantedBy = [ "multi-user.target" ];
serviceConfig = {
DynamicUser = true;
StateDirectory = "irccat";
WorkingDirectory = "/var/lib/irccat";
Restart = "always";
};
};
};
}