From 6635ea516dd102c9a900ede630598b026473165e Mon Sep 17 00:00:00 2001
From: Max <max@privatevoid.net>
Date: Sun, 27 Aug 2023 16:25:44 +0200
Subject: [PATCH] modules/consul-distributed-services: init

---
 .../consul-distributed-services/default.nix   | 43 +++++++++++++++++++
 modules/part.nix                              |  2 +
 2 files changed, 45 insertions(+)
 create mode 100644 modules/consul-distributed-services/default.nix

diff --git a/modules/consul-distributed-services/default.nix b/modules/consul-distributed-services/default.nix
new file mode 100644
index 0000000..1297a84
--- /dev/null
+++ b/modules/consul-distributed-services/default.nix
@@ -0,0 +1,43 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  consul = config.services.consul.package;
+in
+{
+  options.systemd.services = mkOption {
+    type = with types; attrsOf (submodule ({ config, ... }: let
+      cfg = config.distributed;
+    in {
+      config = mkIf cfg.enable {
+
+      };
+    }));
+  };
+
+  config.systemd.packages = pipe config.systemd.services [
+    (filterAttrs (_: v: v.distributed.enable))
+    (mapAttrsToList (n: v: let
+      inherit (v.serviceConfig) ExecStart;
+
+      cfg = v.distributed;
+
+      svc = config.consul.services.${cfg.registerService};
+
+      runWithRegistration = pkgs.writeShellScript "run-with-registration" ''
+        trap '${svc.commands.deregister}' EXIT
+        ${svc.commands.register}
+        ''${@}
+      '';
+
+      hasSpecialPrefix = elem (substring 0 1 ExecStart) [ "@" "-" ":" "+" "!" ];
+    in assert !hasSpecialPrefix; pkgs.writeTextDir "etc/systemd/system/${n}.service.d/distributed.conf" ''
+      [Service]
+      ExecStart=
+      ExecStart=${consul}/bin/consul lock --name=${n} --n=${toString cfg.replicas} --shell=false --child-exit-code 'services/${n}%i' ${optionalString (cfg.registerService != null) runWithRegistration} ${ExecStart}
+      ${optionalString (v.serviceConfig ? RestrictAddressFamilies) "RestrictAddressFamilies=AF_NETLINK"}
+      ${optionalString (cfg.registerService != null) "ExecStopPost=${svc.commands.deregister}"}
+    ''))
+  ];
+}
diff --git a/modules/part.nix b/modules/part.nix
index 311c1c5..00159ad 100644
--- a/modules/part.nix
+++ b/modules/part.nix
@@ -7,6 +7,7 @@ in
 {
   flake.nixosModules = with config.flake.nixosModules; {
     autopatch = ./autopatch;
+    consul-distributed-services = ./consul-distributed-services;
     consul-service-registry = ./consul-service-registry;
     deploy-rs-receiver = ./deploy-rs-receiver;
     effect-receiver = ./effect-receiver;
@@ -44,6 +45,7 @@ in
 
     serverBase = group [
       machineBase
+      consul-distributed-services
       consul-service-registry
       deploy-rs-receiver
       effect-receiver