nix-bitcoin/modules/clightning.nix

{ config, lib, pkgs, ... }:

with lib;

let
  cfg = config.services.clightning;
  configFile = pkgs.writeText "config" ''
    autolisten=${if cfg.autolisten then "true" else "false"}
    network=bitcoin
    bitcoin-rpcuser=${cfg.bitcoin-rpcuser}
  '';
in {
  options.services.clightning = {
    enable = mkOption {
      type = types.bool;
      default = false;
      description = ''
        If enabled, the clightning service will be installed.
      '';
    };
    autolisten = mkOption {
      type = types.bool;
      default = false;
      description = ''
        If enabled, the clightning service will listen.
      '';
    };
    bitcoin-rpcuser = mkOption {
      type = types.string;
      description = ''
        Bitcoin RPC user
      '';
    };
    dataDir = mkOption {
      type = types.path;
      default = "/var/lib/clightning";
      description = "The data directory for clightning.";
    };
  };

  config = mkIf cfg.enable {
    users.users.clightning = {
        description = "clightning User";
        group = "clightning";
        extraGroups = [ "bitcoinrpc" "keys" ];
        home = cfg.dataDir;
    };
    users.groups.clightning = {
      name = "clightning";
    };

    systemd.services.clightning = {
      description = "Run clightningd";
      path  = [ pkgs.bitcoin ];
      wantedBy = [ "multi-user.target" ];
      requires = [ "bitcoind.service" ];
      after = [ "bitcoind.service" ];
      preStart = ''
        mkdir -m 0770 -p ${cfg.dataDir}
        rm -f ${cfg.dataDir}/config
        chown 'clightning:clightning' '${cfg.dataDir}'
        cp ${configFile} ${cfg.dataDir}/config
        chown 'clightning:clightning' '${cfg.dataDir}/config'
        chmod +w ${cfg.dataDir}/config
        chmod o-rw ${cfg.dataDir}/config
        # The RPC socket has to be removed otherwise we might have stale sockets
        rm -f ${cfg.dataDir}/lightning-rpc
        echo "bitcoin-rpcpassword=$(cat /secrets/bitcoin-rpcpassword)" >> '${cfg.dataDir}/config'
        '';
      serviceConfig = {
        PermissionsStartOnly = "true";
        ExecStart = "${pkgs.clightning}/bin/lightningd --lightning-dir=${cfg.dataDir}";
        User = "clightning";
        Restart = "on-failure";
        RestartSec = "10s";
        PrivateTmp = "true";
        ProtectSystem = "full";
        NoNewPrivileges = "true";
        PrivateDevices = "true";
        MemoryDenyWriteExecute = "true";
      };
    };
  };
}