nixos/mautrix-telegram: add module (#63589)

nixos/modules/module-list.nix

@@ -464,6 +464,7 @@
   ./services/misc/mathics.nix
   ./services/misc/matrix-appservice-discord.nix
   ./services/misc/matrix-synapse.nix
+  ./services/misc/mautrix-telegram.nix
   ./services/misc/mbpfan.nix
   ./services/misc/mediatomb.nix
   ./services/misc/mesos-master.nix

nixos/modules/services/misc/mautrix-telegram.nix

@@ -0,0 +1,163 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  dataDir = "/var/lib/mautrix-telegram";
+  registrationFile = "${dataDir}/telegram-registration.yaml";
+  cfg = config.services.mautrix-telegram;
+  # TODO: switch to configGen.json once RFC42 is implemented
+  settingsFile = pkgs.writeText "mautrix-telegram-settings.json" (builtins.toJSON cfg.settings);
+
+in {
+  options = {
+    services.mautrix-telegram = {
+      enable = mkEnableOption "Mautrix-Telegram, a Matrix-Telegram hybrid puppeting/relaybot bridge";
+
+      settings = mkOption rec {
+        # TODO: switch to types.config.json as prescribed by RFC42 once it's implemented
+        type = types.attrs;
+        apply = recursiveUpdate default;
+        default = {
+          appservice = rec {
+            database = "sqlite:///${dataDir}/mautrix-telegram.db";
+            hostname = "0.0.0.0";
+            port = 8080;
+            address = "http://localhost:${toString port}";
+          };
+
+          bridge = {
+            permissions."*" = "relaybot";
+            relaybot.whitelist = [ ];
+          };
+
+          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" ];
+            };
+          };
+        };
+        example = literalExample ''
+          {
+            homeserver = {
+              address = "http://localhost:8008";
+              domain = "public-domain.tld";
+            };
+
+            appservice.public = {
+              prefix = "/public";
+              external = "https://public-appservice-address/public";
+            };
+
+            bridge.permissions = {
+              "example.com" = "full";
+              "@admin:example.com" = "admin";
+            };
+          }
+        '';
+        description = ''
+          <filename>config.yaml</filename> configuration as a Nix attribute set.
+          Configuration options should match those described in
+          <link xlink:href="https://github.com/tulir/mautrix-telegram/blob/master/example-config.yaml">
+          example-config.yaml</link>.
+          </para>
+
+          <para>
+          Secret tokens should be specified using <option>environmentFile</option>
+          instead of this world-readable attribute set.
+        '';
+      };
+
+      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>.
+        '';
+      };
+
+      serviceDependencies = mkOption {
+        type = with types; listOf str;
+        default = optional config.services.matrix-synapse.enable "matrix-synapse.service";
+        description = ''
+          List of Systemd services to require and wait for when starting the application service.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.mautrix-telegram = {
+      description = "Mautrix-Telegram, a Matrix-Telegram hybrid puppeting/relaybot bridge.";
+
+      wantedBy = [ "multi-user.target" ];
+      wants = [ "network-online.target" ] ++ cfg.serviceDependencies;
+      after = [ "network-online.target" ] ++ cfg.serviceDependencies;
+
+      preStart = ''
+        # generate the appservice's registration file if absent
+        if [ ! -f '${registrationFile}' ]; then
+          ${pkgs.mautrix-telegram}/bin/mautrix-telegram \
+            --generate-registration \
+            --base-config='${pkgs.mautrix-telegram}/example-config.yaml' \
+            --config='${settingsFile}' \
+            --registration='${registrationFile}'
+        fi
+
+        # run automatic database init and migration scripts
+        ${pkgs.mautrix-telegram.alembic}/bin/alembic -x config='${settingsFile}' upgrade head
+      '';
+
+      serviceConfig = {
+        Type = "simple";
+        Restart = "always";
+
+        ProtectSystem = "strict";
+        ProtectHome = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+
+        DynamicUser = true;
+        PrivateTmp = true;
+        WorkingDirectory = pkgs.mautrix-telegram; # necessary for the database migration scripts to be found
+        StateDirectory = baseNameOf dataDir;
+        UMask = 0027;
+        EnvironmentFile = cfg.environmentFile;
+
+        ExecStart = ''
+          ${pkgs.mautrix-telegram}/bin/mautrix-telegram \
+            --config='${settingsFile}'
+        '';
+      };
+    };
+  };
+
+  meta.maintainers = with maintainers; [ pacien vskilet ];
+}