feat(modules): add inadyn NixOS module

flake.nix

@@ -89,6 +89,7 @@ rec {
         nixosModules = {
           flakeDefaults = import ./modules/flakeDefaults.nix;
           systemdNotify = import ./modules/systemdNotify.nix;
+          inadyn = import ./modules/inadyn.nix;
         };
 
         homeManagerModules = {

modules/inadyn.nix

@@ -0,0 +1,173 @@
+{ config, lib, pkgs, ... }:
+
+let
+  inherit (lib) mkEnableOption mkOption types mkIf;
+  cfg = config.services.inadyn;
+
+  mkConfig = ipCfg: domain: ''
+    username = ${cfg.username}
+    password = $INADYN_PASSWORD
+    hostname = ${domain}
+    ${lib.optionalString (ipCfg.server != null) ''
+      checkip-server = ${ipCfg.server}
+    ''}
+    ${lib.optionalString (ipCfg.command != null) ''
+      checkip-command = ${ipCfg.command}
+    ''}
+    ${cfg.extraConfig}
+    ${ipCfg.extraConfig}
+  '';
+in {
+  options = {
+    services.inadyn = {
+      enable = mkOption {
+        type = types.bool;
+        default = false;
+        description = "Enable inadyn DDNS client.";
+      };
+
+      dataDir = mkOption {
+        type = types.str;
+        default = "/var/lib/inadyn";
+        description = "Data directory.";
+      };
+
+      cacheDir = mkOption {
+        type = types.str;
+        default = "/var/cache/inadyn";
+        description = "Cache directory.";
+      };
+
+      provider = mkOption {
+        type = types.str;
+        default = null;
+        example = "cloudflare.com";
+        description = "DNS Provider.";
+      };
+
+      username = mkOption {
+        type = types.str;
+        default = null;
+        description = "Username for the DNS provider.";
+      };
+
+      passwordFile = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        example = "/run/keys/inadyn-password";
+        description = "Secret for the DNS provider.";
+      };
+
+      domains = mkOption {
+        type = types.listOf types.str;
+        default = [ ];
+        example = [ "host.tld" ];
+        description = "List of domain names to update records for.";
+      };
+
+      ipv4.enable =
+        mkEnableOption (lib.mdDoc "Whether to update IPv4 records.");
+
+      ipv4.server = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "Server to query IPv4 address.";
+      };
+
+      ipv4.command = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "Command to get IPv4 address.";
+      };
+
+      ipv4.extraConfig = mkOption {
+        type = types.nullOr types.str;
+        default = "";
+        example = ''
+          proxied = false
+        '';
+        description = "Extra configuration add to each IPv4 domain config.";
+      };
+
+      ipv6.enable =
+        mkEnableOption (lib.mdDoc "Whether to update IPv6 records.");
+
+      ipv6.server = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "Server to query IPv6 address.";
+      };
+
+      ipv6.command = mkOption {
+        type = types.nullOr types.str;
+        default = null;
+        description = "Command to get IPv6 address.";
+      };
+
+      ipv6.extraConfig = mkOption {
+        type = types.nullOr types.str;
+        default = "";
+        example = ''
+          proxied = false
+        '';
+        description = "Extra configuration add to each IPv6 domain config.";
+      };
+
+      extraConfig = mkOption {
+        type = types.str;
+        default = "";
+        example = ''
+          proxied = false
+        '';
+        description = "Extra configuration add to each domain config.";
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.inadyn = {
+      description = "inadyn DDNS client";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+      startAt = "*:0/5";
+      serviceConfig = rec {
+        Type = "simple";
+        LoadCredential = lib.optionalString (cfg.passwordFile != null)
+          "INADYN_PASSWORD:${cfg.passwordFile}";
+        ExecStart = pkgs.writeScript "run-inadyn.sh" ''
+          #!${pkgs.bash}/bin/bash
+          export PATH=$PATH:${pkgs.bash}/bin/bash # idk if that helps
+
+          ${lib.optionalString (cfg.passwordFile != null) ''
+            export INADYN_PASSWORD=$(cat "$CREDENTIALS_DIRECTORY/INADYN_PASSWORD")
+          ''}
+
+          cat >/run/${RuntimeDirectory}/inadyn.cfg <<EOF
+          period = 180
+          user-agent = Mozilla/5.0
+          ${lib.optionalString cfg.ipv6.enable ''
+            allow-ipv6 = true
+          ''}
+          ${lib.concatImapStrings (i: domain:
+            (lib.optionalString cfg.ipv4.enable ''
+              # ipv4
+              provider ${cfg.provider}:${toString (i * 2)} {
+                ${mkConfig cfg.ipv4 domain}
+              }
+            '' + lib.optionalString cfg.ipv6.enable ''
+              # ipv6
+              provider ${cfg.provider}:${toString (i * 2 + 1)} {
+                ${mkConfig cfg.ipv6 domain}
+              }
+            '')) cfg.domains}
+          EOF
+          exec ${pkgs.inadyn}/bin/inadyn -n ${cfg.cacheDir} -f /run/${RuntimeDirectory}/inadyn.cfg
+        '';
+        RuntimeDirectory = StateDirectory;
+        StateDirectory = builtins.baseNameOf cfg.dataDir;
+      };
+    };
+
+    systemd.tmpfiles.rules = [ "d ${cfg.cacheDir} 1777 root root 10m" ];
+  };
+}