From 32f093fcbecf284e39763109e828b3e63c57597a Mon Sep 17 00:00:00 2001
From: Rubikoid <rubikoid@rubikoid.ru>
Date: Wed, 10 Jul 2024 19:29:47 +0300
Subject: [PATCH] services/yggdrasil: init

---
 modules/module-list.nix        |   1 +
 modules/services/yggdrasil.nix | 127 +++++++++++++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 modules/services/yggdrasil.nix

diff --git a/modules/module-list.nix b/modules/module-list.nix
index e87f696c..7f0c643f 100644
--- a/modules/module-list.nix
+++ b/modules/module-list.nix
@@ -86,6 +86,7 @@
   ./services/trezord.nix
   ./services/wg-quick.nix
   ./services/yabai
+  ./services/yggdrasil.nix
   ./services/nextdns
   ./programs/bash
   ./programs/direnv.nix
diff --git a/modules/services/yggdrasil.nix b/modules/services/yggdrasil.nix
new file mode 100644
index 00000000..08c2b51f
--- /dev/null
+++ b/modules/services/yggdrasil.nix
@@ -0,0 +1,127 @@
+{ config, lib, pkgs, ... }:
+with lib;
+let
+  cfg = config.services.yggdrasil;
+
+  settingsProvided = cfg.settings != { };
+  configFileProvided = cfg.configFile != null;
+
+  format = pkgs.formats.json { };
+in
+{
+  meta.maintainers = [ "rubikoid" ];
+
+  options = with types; {
+    services.yggdrasil = {
+      enable = mkEnableOption "the yggdrasil system service";
+
+      settings = mkOption {
+        type = format.type;
+        default = { };
+        example = {
+          Peers = [
+            "tcp://aa.bb.cc.dd:eeeee"
+            "tcp://[aaaa:bbbb:cccc:dddd::eeee]:fffff"
+          ];
+          Listen = [
+            "tcp://0.0.0.0:xxxxx"
+          ];
+        };
+        description = ''
+          Configuration for yggdrasil, as a Nix attribute set.
+
+          Warning: this is stored in the WORLD-READABLE Nix store!
+          Therefore, it is not appropriate for private keys. If you
+          wish to specify the keys, use {option}`configFile`.
+
+          If no keys are specified then ephemeral keys are generated
+          and the Yggdrasil interface will have a random IPv6 address
+          each time the service is started. This is the default.
+
+          If both {option}`configFile` and {option}`settings`
+          are supplied, they will be combined, with values from
+          {option}`configFile` taking precedence.
+
+          You can use the command `nix-shell -p yggdrasil --run "yggdrasil -genconf"`
+          to generate default configuration values with documentation.
+        '';
+      };
+
+      configFile = mkOption {
+        type = nullOr path;
+        default = null;
+        example = "/run/keys/yggdrasil.conf";
+        description = lib.mdDoc ''
+          A file which contains JSON or HJSON configuration for yggdrasil. See
+          the {option}`settings` option for more information.
+
+          On NixOS, file in this option is limited to 1 MB due to limitations 
+          in systemd. If you would like to share your yggdrasil configuration
+          between nix-darwin and NixOS, you should keep this limitation in mind,
+          even though there is no equivalent limit on macOS.
+        '';
+      };
+
+      package = mkPackageOption pkgs "yggdrasil" { };
+
+      extraArgs = mkOption {
+        type = listOf str;
+        default = [ ];
+        example = [ "-loglevel" "info" ];
+        description = lib.mdDoc "Extra command line arguments.";
+      };
+
+      logFile = mkOption {
+        type = nullOr path;
+        default = null;
+        example = "/var/log/yggdrasil.log";
+        description = "Path to logfile with stdout and stderr of yggdrsail daemon";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable (
+    let
+      yggdrasilConf = "/run/yggdrasil/yggdrasil.conf";
+      binYggdrasil = "${cfg.package}/bin/yggdrasil";
+      binHjson = "${pkgs.hjson-go}/bin/hjson-cli";
+      binJq = "${pkgs.jq}/bin/jq";
+    in
+    {
+      environment.systemPackages = [ cfg.package ];
+
+      # have to write it in that way to not interfere with brew's (or idk github?) ygg.plist
+      launchd.daemons.ygg =
+        {
+          script = ''
+            set -euo pipefail
+
+            mkdir -p $(dirname ${yggdrasilConf})
+
+            # prepare config file
+            ${(if settingsProvided || configFileProvided then
+              "echo "
+
+              + (lib.optionalString settingsProvided
+                "'${builtins.toJSON cfg.settings}'")
+              + (lib.optionalString configFileProvided
+                "$(${binHjson} -c ${cfg.configFile})")
+              + " | ${binJq} -s add | ${binYggdrasil} -normaliseconf -useconf > ${yggdrasilConf}"
+            else
+              "if [ ! -f '${yggdrasilConf}' ]; then ${binYggdrasil} -genconf > ${yggdrasilConf}; fi")}
+
+            # start yggdrasil
+            ${binYggdrasil} -useconffile ${yggdrasilConf} ${lib.strings.escapeShellArgs cfg.extraArgs}
+          '';
+
+          serviceConfig = {
+            ProcessType = "Interactive";
+            StandardOutPath = cfg.logFile;
+            StandardErrorPath = cfg.logFile;
+            KeepAlive = true;
+            RunAtLoad = true;
+          };
+        };
+    }
+  );
+}