dgraph: add module

nixos/modules/module-list.nix

@@ -351,6 +351,7 @@
   ./services/databases/cockroachdb.nix
   ./services/databases/couchdb.nix
   ./services/databases/dragonflydb.nix
+  ./services/databases/dgraph.nix
   ./services/databases/firebird.nix
   ./services/databases/foundationdb.nix
   ./services/databases/hbase.nix

nixos/modules/services/databases/dgraph.nix

@@ -0,0 +1,148 @@
+{ config, pkgs, lib, ... }:
+
+with lib;
+
+let
+  cfg = config.services.dgraph;
+  settingsFormat = pkgs.formats.json {};
+  configFile = settingsFormat.generate "config.json" cfg.settings;
+  dgraphWithNode = pkgs.runCommand "dgraph" {
+    nativeBuildInputs = [ pkgs.makeWrapper ];
+  }
+  ''
+    mkdir -p $out/bin
+    makeWrapper ${cfg.package}/bin/dgraph $out/bin/dgraph \
+      --set PATH '${lib.makeBinPath [ pkgs.nodejs ]}:$PATH' \
+  '';
+  securityOptions = {
+      NoNewPrivileges = true;
+
+      AmbientCapabilities = "";
+      CapabilityBoundingSet = "";
+
+      DeviceAllow = "";
+
+      LockPersonality = true;
+
+      PrivateTmp = true;
+      PrivateDevices = true;
+      PrivateUsers = true;
+
+      ProtectClock = true;
+      ProtectControlGroups = true;
+      ProtectHostname = true;
+      ProtectKernelLogs = true;
+      ProtectKernelModules = true;
+      ProtectKernelTunables = true;
+
+      RemoveIPC = true;
+
+      RestrictNamespaces = true;
+      RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_UNIX" ];
+      RestrictRealtime = true;
+      RestrictSUIDSGID = true;
+
+      SystemCallArchitectures = "native";
+      SystemCallErrorNumber = "EPERM";
+      SystemCallFilter = [
+        "@system-service"
+        "~@cpu-emulation" "~@debug" "~@keyring" "~@memlock" "~@obsolete" "~@privileged" "~@setuid"
+      ];
+  };
+in
+{
+  options = {
+    services.dgraph = {
+      enable = mkEnableOption "Dgraph native GraphQL database with a graph backend";
+
+      package = lib.mkPackageOption pkgs "dgraph" { };
+
+      settings = mkOption {
+        type = settingsFormat.type;
+        default = {};
+        description = ''
+          Contents of the dgraph config. For more details see https://dgraph.io/docs/deploy/config
+        '';
+      };
+
+      alpha = {
+        host = mkOption {
+          type = types.str;
+          default = "localhost";
+          description = ''
+            The host which dgraph alpha will be run on.
+          '';
+        };
+        port = mkOption {
+          type = types.port;
+          default = 7080;
+          description = ''
+            The port which to run dgraph alpha on.
+          '';
+        };
+
+      };
+
+      zero = {
+        host = mkOption {
+          type = types.str;
+          default = "localhost";
+          description = ''
+            The host which dgraph zero will be run on.
+          '';
+        };
+        port = mkOption {
+          type = types.port;
+          default = 5080;
+          description = ''
+            The port which to run dgraph zero on.
+          '';
+        };
+      };
+
+    };
+  };
+
+  config = mkIf cfg.enable {
+    services.dgraph.settings = {
+      badger.compression = mkDefault "zstd:3";
+    };
+
+    systemd.services.dgraph-zero = {
+      description = "Dgraph native GraphQL database with a graph backend. Zero controls node clustering";
+      after = [ "network.target" ];
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        StateDirectory = "dgraph-zero";
+        WorkingDirectory = "/var/lib/dgraph-zero";
+        DynamicUser = true;
+        ExecStart = "${cfg.package}/bin/dgraph zero --my ${cfg.zero.host}:${toString cfg.zero.port}";
+        Restart = "on-failure";
+      } // securityOptions;
+    };
+
+    systemd.services.dgraph-alpha = {
+      description = "Dgraph native GraphQL database with a graph backend. Alpha serves data";
+      after = [ "network.target" "dgraph-zero.service" ];
+      requires = [ "dgraph-zero.service" ];
+      wantedBy = [ "multi-user.target" ];
+
+      serviceConfig = {
+        StateDirectory = "dgraph-alpha";
+        WorkingDirectory = "/var/lib/dgraph-alpha";
+        DynamicUser = true;
+        ExecStart = "${dgraphWithNode}/bin/dgraph alpha --config ${configFile} --my ${cfg.alpha.host}:${toString cfg.alpha.port} --zero ${cfg.zero.host}:${toString cfg.zero.port}";
+        ExecStop = ''
+          ${pkgs.curl}/bin/curl --data "mutation { shutdown { response { message code } } }" \
+              --header 'Content-Type: application/graphql' \
+              -X POST \
+              http://localhost:8080/admin
+        '';
+        Restart = "on-failure";
+      } // securityOptions;
+    };
+  };
+
+  meta.maintainers = with lib.maintainers; [ happysalada ];
+}