settei/modules/flake/services.nix

95 lines
2.6 KiB
Nix

# List of features I want this module to eventually have
# TODO: Automatic port allocation
# TODO: Making it possible to conveniently isolate services (running them in NixOS containers)
# TODO: Handling specializations
# TODO: Convenient http handling
# TODO: Automatic backup
{ config, lib, ... }:
let
serviceModule =
{ config, ... }:
{
options = {
host = lib.mkOption {
type = lib.types.str;
};
ports = lib.mkOption {
type = with lib.types; listOf port;
default = [ ];
};
hosts = lib.mkOption {
type = with lib.types; listOf str;
default = [ config.host ];
};
module = lib.mkOption {
type = lib.types.deferredModule;
default = { };
};
hostModule = lib.mkOption {
type = with lib.types; attrsOf deferredModule;
default = { };
};
};
};
moduleToHostConfigs =
cfg:
lib.genAttrs cfg.hosts (host: {
imports = [
cfg.module
(cfg.hostModule.${host} or { })
];
});
maybeGetPreviousConfigs = acc: host: (acc.${host} or { imports = [ ]; }).imports;
in
{
_file = ./services.nix;
options = {
services = lib.mkOption {
type = with lib.types; attrsOf (submodule serviceModule);
default = { };
};
__extraHostConfigs = lib.mkOption {
type = with lib.types; attrsOf deferredModule;
readOnly = true;
};
};
config.__extraHostConfigs =
let
duplicatePorts = lib.pipe config.services [
lib.attrValues
(map (cfg: cfg.ports))
lib.flatten
(lib.groupBy' (cnt: _: cnt + 1) 0 toString)
(lib.filterAttrs (_: cnt: cnt > 1))
lib.attrNames
];
assertMsg =
let
plural = lib.length duplicatePorts > 1;
in
"\nBad service config:\nThe following port${if plural then "s" else ""} ${
if plural then "were" else "was"
} declared multiple times: ${lib.concatStringsSep ", " duplicatePorts}";
# Here I collect all the services.<name>.config into a flat
# __extraHostConfigs.<host>.imports = [
# ...
# ]
# so that I can easily import them in hosts/default.nix
hostConfigs = lib.pipe config.services [
lib.attrValues
(lib.foldl' (
acc: cfg:
acc
// lib.mapAttrs (host: c: {
imports = c.imports ++ (maybeGetPreviousConfigs acc host);
}) (moduleToHostConfigs cfg)
) { })
];
in
if duplicatePorts != [ ] then throw assertMsg else hostConfigs;
}