nixos-config/modules/matrix/mautrix-signal.nix

# Copyright © 2023 Eelco Dolstra and the Nixpkgs/NixOS contributors
#
# Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the “Software”), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
{
  config,
  pkgs,
  lib,
  ...
}:
with lib; let
  dataDir = "/var/lib/mautrix-signal";
  registrationFile = config.sops.secrets."services/mautrix/signal.yaml".path;
  cfg = config.services.mautrix-signal;
  settingsFormat = pkgs.formats.yaml {};
  settingsFileUnsubstituted = settingsFormat.generate "mautrix-signal-config-unsubstituted.yaml" cfg.settings;
  settingsFile = "${dataDir}/config.yaml";
in {
  options = {
    services.mautrix-signal = {
      enable = mkEnableOption "Mautrix-signal, a mautrix-signal hybrid puppeting/relaybot bridge";
      settings = mkOption rec {
        apply = recursiveUpdate default;
        inherit (settingsFormat) type;
        default = {
          appservice = {
            address = "http://mautrix-signal.int.chir.rs:29328";
            hostname = "0.0.0.0";
            port = 29328;
            database = "sqlite:///${dataDir}/mautrix-signal.db";
            as_token = "$AS_TOKEN";
            hs_token = "$HS_TOKEN";
          };
          logging = {
            version = 1;

            formatters.precise.format = "[%(levelname)s@%(name)s] %(message)s";

            handlers.console = {
              class = "logging.StreamHandler";
              formatter = "precise";
            };

            loggers = {
              mau.level = "INFO";
              telethon.level = "INFO";

              # prevent tokens from leaking in the logs:
              # https://github.com/tulir/mautrix-telegram/issues/351
              aiohttp.level = "WARNING";
            };

            # log to console/systemd instead of file
            root = {
              level = "INFO";
              handlers = ["console"];
            };
          };
        };
      };
      environmentFile = mkOption {
        type = types.nullOr types.path;
        default = null;
        description = ''
          File containing environment variables to be passed to the mautrix-telegram service,
          in which secret tokens can be specified securely by defining values for
          <literal>MAUTRIX_TELEGRAM_APPSERVICE_AS_TOKEN</literal>,
          <literal>MAUTRIX_TELEGRAM_APPSERVICE_HS_TOKEN</literal>,
          <literal>MAUTRIX_TELEGRAM_TELEGRAM_API_ID</literal>,
          <literal>MAUTRIX_TELEGRAM_TELEGRAM_API_HASH</literal> and optionally
          <literal>MAUTRIX_TELEGRAM_TELEGRAM_BOT_TOKEN</literal>.
        '';
      };
    };
  };
  config = mkIf cfg.enable {
    systemd.services.mautrix-signal-genregistration = {
      description = "Mautrix-signal Registration";
      script = ''
        # Not all secrets can be passed as environment variable (yet)
        # https://github.com/tulir/mautrix-telegram/issues/584
        [ -f ${settingsFile} ] && rm -f ${settingsFile}
        export AS_TOKEN=$(${pkgs.yq}/bin/yq -r '.as_token' ${registrationFile})
        export HS_TOKEN=$(${pkgs.yq}/bin/yq -r '.hs_token' ${registrationFile})
        umask 0177
        ${pkgs.envsubst}/bin/envsubst \
          -o ${settingsFile} \
          -i ${settingsFileUnsubstituted}
        umask $old_umask
      '';
      serviceConfig = {
        Type = "oneshot";
        RemainAfterExit = true;
        ProtectSystem = "strict";
        ProtectHome = true;
        ProtectKernelTunables = true;
        ProtectKernelModules = true;
        ProtectControlGroups = true;
        WorkingDirectory = dataDir;
        StateDirectory = baseNameOf dataDir;
        UMask = 0117;
        User = "mautrix-signal";
        Group = "mautrix-signal";
        EnvironmentFile = cfg.environmentFile;
      };
      restartTriggers = [settingsFileUnsubstituted cfg.environmentFile];
    };
    systemd.services.mautrix-signal = {
      description = "Mautrix-signal";
      wantedBy = ["multi-user.target"];
      wants = ["mautrix-signal-genregistration.service" "signald.service"];
      after = ["mautrix-signal-genregistration.service" "signald.service"];
      serviceConfig = {
        Type = "simple";
        Restart = "always";

        WorkingDirectory = dataDir;
        User = "mautrix-signal";
        Group = "mautrix-signal";
        EnvironmentFile = cfg.environmentFile;
        ExecStart = ''
          ${pkgs.mautrix-signal}/bin/mautrix-signal \
            --config='${settingsFile}'
        '';
      };
      restartTriggers = [cfg.environmentFile];
    };
    users.users.mautrix-signal = {
      description = "Mautrix signal bridge";
      home = "${dataDir}";
      useDefaultShell = true;
      group = "mautrix-signal";
      isSystemUser = true;
    };
    users.groups.mautrix-signal = {};
    services.signald = {
      user = "mautrix-signal";
      group = "mautrix-signal";
      enable = true;
    };
    sops.secrets."services/mautrix/signal.yaml".owner = "mautrix-signal";
  };
}