nixos/fedimintd: init services

nixos/doc/manual/release-notes/rl-2411.section.md

···
 
 - [Veilid](https://veilid.com), a headless server that enables privacy-focused data sharing and messaging on a peer-to-peer network. Available as [services.veilid](#opt-services.veilid.enable).
 
+- [Fedimint](https://github.com/fedimint/fedimint), a module based system for building federated applications (Federated E-Cash Mint). Available as [services.fedimintd](#opt-services.fedimintd).
+
 ## Backward Incompatibilities {#sec-release-24.11-incompatibilities}
 
 - The `sound` options have been removed or renamed, as they had a lot of unintended side effects. See [below](#sec-release-24.11-migration-sound) for details.

nixos/modules/module-list.nix

···
   ./services/networking/expressvpn.nix
   ./services/networking/fakeroute.nix
   ./services/networking/fastnetmon-advanced.nix
+  ./services/networking/fedimintd.nix
   ./services/networking/ferm.nix
   ./services/networking/firefox-syncserver.nix
   ./services/networking/fireqos.nix

nixos/modules/services/networking/fedimintd.nix

···
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  inherit (lib)
+    concatLists
+    filterAttrs
+    mapAttrs'
+    mapAttrsToList
+    mkEnableOption
+    mkIf
+    mkOption
+    mkOverride
+    mkPackageOption
+    nameValuePair
+    recursiveUpdate
+    types
+    ;
+
+  fedimintdOpts =
+    {
+      config,
+      lib,
+      name,
+      ...
+    }:
+    {
+      options = {
+        enable = mkEnableOption "fedimintd";
+
+        package = mkPackageOption pkgs "fedimint" { };
+
+        environment = mkOption {
+          type = types.attrsOf types.str;
+          description = "Extra Environment variables to pass to the fedimintd.";
+          default = {
+            RUST_BACKTRACE = "1";
+          };
+          example = {
+            RUST_LOG = "info,fm=debug";
+            RUST_BACKTRACE = "1";
+          };
+        };
+
+        p2p = {
+          openFirewall = mkOption {
+            type = types.bool;
+            default = true;
+            description = "Opens port in firewall for fedimintd's p2p port";
+          };
+          port = mkOption {
+            type = types.port;
+            default = 8173;
+            description = "Port to bind on for p2p connections from peers";
+          };
+          bind = mkOption {
+            type = types.str;
+            default = "0.0.0.0";
+            description = "Address to bind on for p2p connections from peers";
+          };
+          url = mkOption {
+            type = types.str;
+            example = "fedimint://p2p.myfedimint.com";
+            description = ''
+              Public address for p2p connections from peers
+            '';
+          };
+        };
+        api = {
+          openFirewall = mkOption {
+            type = types.bool;
+            default = false;
+            description = "Opens port in firewall for fedimintd's api port";
+          };
+          port = mkOption {
+            type = types.port;
+            default = 8174;
+            description = "Port to bind on for API connections relied by the reverse proxy/tls terminator.";
+          };
+          bind = mkOption {
+            type = types.str;
+            default = "127.0.0.1";
+            description = "Address to bind on for API connections relied by the reverse proxy/tls terminator.";
+          };
+          url = mkOption {
+            type = types.str;
+            description = ''
+              Public URL of the API address of the reverse proxy/tls terminator. Usually starting with `wss://`.
+            '';
+          };
+        };
+        bitcoin = {
+          network = mkOption {
+            type = types.str;
+            default = "signet";
+            example = "bitcoin";
+            description = "Bitcoin network to participate in.";
+          };
+          rpc = {
+            url = mkOption {
+              type = types.str;
+              default = "http://127.0.0.1:38332";
+              example = "signet";
+              description = "Bitcoin node (bitcoind/electrum/esplora) address to connect to";
+            };
+
+            kind = mkOption {
+              type = types.str;
+              default = "bitcoind";
+              example = "electrum";
+              description = "Kind of a bitcoin node.";
+            };
+
+            secretFile = mkOption {
+              type = types.nullOr types.path;
+              default = null;
+              description = ''
+                If set the URL specified in `bitcoin.rpc.url` will get the content of this file added
+                as an URL password, so `http://[e-mail]` will turn into `http://user:[e-mail]`.
+
+                Example:
+
+                `/etc/nix-bitcoin-secrets/bitcoin-rpcpassword-public` (for nix-bitcoin default)
+              '';
+            };
+          };
+        };
+
+        consensus.finalityDelay = mkOption {
+          type = types.ints.unsigned;
+          default = 10;
+          description = "Consensus peg-in finality delay.";
+        };
+
+        dataDir = mkOption {
+          type = types.path;
+          default = "/var/lib/fedimintd-${name}/";
+          readOnly = true;
+          description = ''
+            Path to the data dir fedimintd will use to store its data.
+            Note that due to using the DynamicUser feature of systemd, this value should not be changed
+            and is set to be read only.
+          '';
+        };
+
+        nginx = {
+          enable = mkOption {
+            type = types.bool;
+            default = false;
+            description = ''
+              Whether to configure nginx for fedimintd
+            '';
+          };
+          fqdn = mkOption {
+            type = types.str;
+            example = "api.myfedimint.com";
+            description = "Public domain of the API address of the reverse proxy/tls terminator.";
+          };
+          config = mkOption {
+            type = types.submodule (
+              recursiveUpdate (import ../web-servers/nginx/vhost-options.nix {
+                inherit config lib;
+              }) { }
+            );
+            default = { };
+            description = "Overrides to the nginx vhost section for api";
+          };
+        };
+      };
+    };
+in
+{
+  options = {
+    services.fedimintd = mkOption {
+      type = types.attrsOf (types.submodule fedimintdOpts);
+      default = { };
+      description = "Specification of one or more fedimintd instances.";
+    };
+  };
+
+  config =
+    let
+      eachFedimintd = filterAttrs (fedimintdName: cfg: cfg.enable) config.services.fedimintd;
+      eachFedimintdNginx = filterAttrs (fedimintdName: cfg: cfg.nginx.enable) eachFedimintd;
+    in
+    mkIf (eachFedimintd != { }) {
+
+      networking.firewall.allowedTCPPorts = concatLists (
+        mapAttrsToList (
+          fedimintdName: cfg:
+          (lib.optional cfg.api.openFirewall cfg.api.port ++ lib.optional cfg.p2p.openFirewall cfg.p2p.port)
+        ) eachFedimintd
+      );
+
+      systemd.services = mapAttrs' (
+        fedimintdName: cfg:
+        (nameValuePair "fedimintd-${fedimintdName}" (
+          let
+            startScript = pkgs.writeShellScript "fedimintd-start" (
+              (
+                if cfg.bitcoin.rpc.secretFile != null then
+                  ''
+                    secret=$(${pkgs.coreutils}/bin/head -n 1 "${cfg.bitcoin.rpc.secretFile}")
+                    prefix="''${FM_BITCOIN_RPC_URL%*@*}"  # Everything before the last '@'
+                    suffix="''${FM_BITCOIN_RPC_URL##*@}"  # Everything after the last '@'
+                    FM_BITCOIN_RPC_URL="''${prefix}:''${secret}@''${suffix}"
+                  ''
+                else
+                  ""
+              )
+              + ''
+                exec ${cfg.package}/bin/fedimintd
+              ''
+            );
+          in
+          {
+            description = "Fedimint Server";
+            documentation = [ "https://github.com/fedimint/fedimint/" ];
+            wantedBy = [ "multi-user.target" ];
+            environment = lib.mkMerge [
+              {
+                FM_BIND_P2P = "${cfg.p2p.bind}:${toString cfg.p2p.port}";
+                FM_BIND_API = "${cfg.api.bind}:${toString cfg.api.port}";
+                FM_P2P_URL = cfg.p2p.url;
+                FM_API_URL = cfg.api.url;
+                FM_DATA_DIR = cfg.dataDir;
+                FM_BITCOIN_NETWORK = cfg.bitcoin.network;
+                FM_BITCOIN_RPC_URL = cfg.bitcoin.rpc.url;
+                FM_BITCOIN_RPC_KIND = cfg.bitcoin.rpc.kind;
+              }
+              cfg.environment
+            ];
+            serviceConfig = {
+              DynamicUser = true;
+
+              StateDirectory = "fedimintd-${fedimintdName}";
+              StateDirectoryMode = "0700";
+              ExecStart = startScript;
+
+              Restart = "always";
+              RestartSec = 10;
+              StartLimitBurst = 5;
+              UMask = "007";
+              LimitNOFILE = "100000";
+
+              LockPersonality = true;
+              MemoryDenyWriteExecute = true;
+              NoNewPrivileges = true;
+              PrivateDevices = true;
+              PrivateMounts = true;
+              PrivateTmp = true;
+              ProtectClock = true;
+              ProtectControlGroups = true;
+              ProtectHostname = true;
+              ProtectKernelLogs = true;
+              ProtectKernelModules = true;
+              ProtectKernelTunables = true;
+              ProtectSystem = "full";
+              RestrictAddressFamilies = [
+                "AF_INET"
+                "AF_INET6"
+              ];
+              RestrictNamespaces = true;
+              RestrictRealtime = true;
+              SystemCallArchitectures = "native";
+              SystemCallFilter = [
+                "@system-service"
+                "~@privileged"
+              ];
+            };
+          }
+        ))
+      ) eachFedimintd;
+
+      services.nginx.virtualHosts = mapAttrs' (
+        fedimintdName: cfg:
+        (nameValuePair cfg.nginx.fqdn (
+          lib.mkMerge [
+            cfg.nginx.config
+
+            {
+              # Note: we want by default to enable OpenSSL, but it seems anything 100 and above is
+              # overriden by default value from vhost-options.nix
+              enableACME = mkOverride 99 true;
+              forceSSL = mkOverride 99 true;
+              # Currently Fedimint API only support JsonRPC on `/ws/` endpoint, so no need to handle `/`
+              locations."/ws/" = {
+                proxyPass = "http://127.0.0.1:${toString cfg.api.port}/";
+                proxyWebsockets = true;
+                extraConfig = ''
+                  proxy_pass_header Authorization;
+                '';
+              };
+            }
+          ]
+        ))
+      ) eachFedimintdNginx;
+    };
+
+  meta.maintainers = with lib.maintainers; [ dpc ];
+}

nixos/tests/all-tests.nix

···
   fancontrol = handleTest ./fancontrol.nix {};
   fanout = handleTest ./fanout.nix {};
   fcitx5 = handleTest ./fcitx5 {};
+  fedimintd = runTest ./fedimintd.nix;
   fenics = handleTest ./fenics.nix {};
   ferm = handleTest ./ferm.nix {};
   ferretdb = handleTest ./ferretdb.nix {};

nixos/tests/fedimintd.nix

···
+# This test runs the fedimintd and verifies that it starts
+
+{ pkgs, ... }:
+
+{
+  name = "fedimintd";
+
+  meta = with pkgs.lib.maintainers; {
+    maintainers = [ dpc ];
+  };
+
+  nodes.machine =
+    { ... }:
+    {
+      services.fedimintd."mainnet" = {
+        enable = true;
+        p2p = {
+          url = "fedimint://example.com";
+        };
+        api = {
+          url = "wss://example.com";
+        };
+        environment = {
+          "FM_REL_NOTES_ACK" = "0_4_xyz";
+        };
+      };
+    };
+
+  testScript =
+    { nodes, ... }:
+    ''
+      start_all()
+
+      machine.wait_for_unit("fedimintd-mainnet.service")
+      machine.wait_for_open_port(${toString nodes.machine.services.fedimintd.mainnet.api.port})
+    '';
+}