nixos/rmfakecloud: init module

Co-authored-by: Roosemberth Palacios

nixos/modules/module-list.nix

@@ -595,6 +595,7 @@
   ./services/misc/redmine.nix
   ./services/misc/rippled.nix
   ./services/misc/ripple-data-api.nix
+  ./services/misc/rmfakecloud.nix
   ./services/misc/serviio.nix
   ./services/misc/safeeyes.nix
   ./services/misc/sdrplay.nix

nixos/modules/services/misc/rmfakecloud.nix

@@ -0,0 +1,147 @@
+{ config, lib, pkgs, ... }:
+
+with lib;
+
+let
+  cfg = config.services.rmfakecloud;
+  serviceDataDir = "/var/lib/rmfakecloud";
+
+in {
+  options = {
+    services.rmfakecloud = {
+      enable = mkEnableOption "rmfakecloud remarkable self-hosted cloud";
+
+      package = mkOption {
+        type = types.package;
+        default = pkgs.rmfakecloud;
+        defaultText = literalExpression "pkgs.rmfakecloud";
+        description = ''
+          rmfakecloud package to use.
+
+          The default does not include the web user interface.
+        '';
+      };
+
+      storageUrl = mkOption {
+        type = types.str;
+        example = "https://local.appspot.com";
+        description = ''
+          URL used by the tablet to access the rmfakecloud service.
+        '';
+      };
+
+      port = mkOption {
+        type = types.port;
+        default = 3000;
+        description = ''
+          Listening port number.
+        '';
+      };
+
+      logLevel = mkOption {
+        type = types.enum [ "info" "debug" "warn" "error" ];
+        default = "info";
+        description = ''
+          Logging level.
+        '';
+      };
+
+      extraSettings = mkOption {
+        type = with types; attrsOf str;
+        default = { };
+        example = { DATADIR = "/custom/path/for/rmfakecloud/data"; };
+        description = ''
+          Extra settings in the form of a set of key-value pairs.
+          For tokens and secrets, use `environmentFile` instead.
+
+          Available settings are listed on
+          https://ddvk.github.io/rmfakecloud/install/configuration/.
+        '';
+      };
+
+      environmentFile = mkOption {
+        type = with types; nullOr path;
+        default = null;
+        example = "/etc/secrets/rmfakecloud.env";
+        description = ''
+          Path to an environment file loaded for the rmfakecloud service.
+
+          This can be used to securely store tokens and secrets outside of the
+          world-readable Nix store. Since this file is read by systemd, it may
+          have permission 0400 and be owned by root.
+        '';
+      };
+    };
+  };
+
+  config = mkIf cfg.enable {
+    systemd.services.rmfakecloud = {
+      description = "rmfakecloud remarkable self-hosted cloud";
+
+      environment = {
+        STORAGE_URL = cfg.storageUrl;
+        PORT = toString cfg.port;
+        LOGLEVEL = cfg.logLevel;
+      } // cfg.extraSettings;
+
+      preStart = ''
+        # Generate the secret key used to sign client session tokens.
+        # Replacing it invalidates the previously established sessions.
+        if [ -z "$JWT_SECRET_KEY" ] && [ ! -f jwt_secret_key ]; then
+          (umask 077; touch jwt_secret_key)
+          cat /dev/urandom | tr -cd '[:alnum:]' | head -c 48 >> jwt_secret_key
+        fi
+      '';
+
+      script = ''
+        if [ -z "$JWT_SECRET_KEY" ]; then
+          export JWT_SECRET_KEY="$(cat jwt_secret_key)"
+        fi
+
+        ${cfg.package}/bin/rmfakecloud
+      '';
+
+      wantedBy = [ "multi-user.target" ];
+      wants = [ "network-online.target" ];
+      after = [ "network-online.target" ];
+
+      serviceConfig = {
+        Type = "simple";
+        Restart = "always";
+
+        EnvironmentFile =
+          mkIf (cfg.environmentFile != null) cfg.environmentFile;
+
+        AmbientCapabilities =
+          mkIf (cfg.port < 1024) [ "CAP_NET_BIND_SERVICE" ];
+
+        DynamicUser = true;
+        PrivateDevices = true;
+        ProtectHome = true;
+        ProtectKernelTunables = true;
+        ProtectKernelModules = true;
+        ProtectControlGroups = true;
+        CapabilityBoundingSet = [ "" ];
+        DevicePolicy = "closed";
+        LockPersonality = true;
+        MemoryDenyWriteExecute = true;
+        ProtectClock = true;
+        ProtectHostname = true;
+        ProtectKernelLogs = true;
+        ProtectProc = "invisible";
+        ProcSubset = "pid";
+        RemoveIPC = true;
+        RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        RestrictSUIDSGID = true;
+        SystemCallArchitectures = "native";
+        WorkingDirectory = serviceDataDir;
+        StateDirectory = baseNameOf serviceDataDir;
+        UMask = 0027;
+      };
+    };
+  };
+
+  meta.maintainers = with maintainers; [ pacien ];
+}