nixos/nezha: init

(cherry picked from commit b5916099b2)

nixos/modules/module-list.nix

@@ -1049,6 +1049,7 @@
   ./services/monitoring/nagios.nix
   ./services/monitoring/netdata.nix
   ./services/monitoring/nezha-agent.nix
+  ./services/monitoring/nezha.nix
   ./services/monitoring/ocsinventory-agent.nix
   ./services/monitoring/opentelemetry-collector.nix
   ./services/monitoring/osquery.nix

nixos/modules/services/monitoring/nezha.nix

@@ -0,0 +1,179 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.services.nezha;
+
+  # nezha uses yaml as the configuration file format.
+  # Since we need to use jq to update the content, so here we generate json
+  settingsFormat = pkgs.formats.json { };
+  configFile = settingsFormat.generate "config.json" cfg.settings;
+in
+{
+  meta.maintainers = with lib.maintainers; [ moraxyc ];
+  options = {
+    services.nezha = {
+      enable = lib.mkEnableOption "Nezha Monitoring";
+
+      package = lib.mkPackageOption pkgs "nezha" { };
+
+      debug = lib.mkEnableOption "verbose log";
+
+      settings = lib.mkOption {
+        description = ''
+          Generate to {file}`config.yaml` as a Nix attribute set.
+          Check the [guide](https://nezha.wiki/en_US/guide/dashboard.html)
+          for possible options.
+        '';
+        type = lib.types.submodule {
+          freeformType = settingsFormat.type;
+
+          options = {
+            listenhost = lib.mkOption {
+              type = lib.types.str;
+              default = "127.0.0.1";
+              description = ''
+                Host on which the nezha web interface and grpc should listen.
+              '';
+            };
+            listenport = lib.mkOption {
+              type = lib.types.port;
+              default = 8008;
+              description = ''
+                Port on which the nezha web interface and grpc should listen.
+              '';
+            };
+
+          };
+        };
+      };
+
+      mutableConfig = lib.mkOption {
+        type = lib.types.bool;
+        default = true;
+        description = ''
+          Whether the config.yaml is writable by Nezha.
+
+          If this option is disabled, changes on the web interface won't
+          be possible. If an config.yaml is present, it will be overwritten.
+        '';
+      };
+
+      jwtSecretFile = lib.mkOption {
+        type = lib.types.path;
+        default = null;
+        description = ''
+          Path to the file containing the secret to sign web requests using JSON Web Tokens.
+        '';
+      };
+
+      agentSecretFile = lib.mkOption {
+        type = lib.types.path;
+        default = null;
+        description = ''
+          Path to the file containing the secret used by agents to connect.
+        '';
+      };
+
+      extraThemes = lib.mkOption {
+        type = lib.types.listOf lib.types.package;
+        default = [ ];
+        example = lib.literalExpression "[ pkgs.nezha-theme-nazhua ]";
+        description = ''
+          A list of additional themes.
+        '';
+      };
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    services.nezha.settings.debug = cfg.debug;
+
+    systemd.services.nezha = {
+      serviceConfig = {
+        Restart = "on-failure";
+        StateDirectory = "nezha";
+        RuntimeDirectory = "nezha";
+        ConfigurationDirectory = "nezha";
+        WorkingDirectory = "/var/lib/nezha";
+        ReadWritePaths = [
+          "/var/lib/nezha"
+          "/etc/nezha"
+        ];
+
+        LoadCredential = [
+          "jwt-secret:${cfg.jwtSecretFile}"
+          "agent-secret:${cfg.agentSecretFile}"
+        ];
+
+        # Hardening
+        ProcSubset = "pid";
+        DynamicUser = true;
+        RemoveIPC = true;
+        LockPersonality = true;
+        ProtectClock = true;
+        MemoryDenyWriteExecute = true;
+        PrivateUsers = cfg.settings.listenport >= 1024; # incompatible with CAP_NET_BIND_SERVICE
+        ProtectHostname = true;
+        RestrictSUIDSGID = true;
+        CapabilityBoundingSet = lib.optionalString (cfg.settings.listenport < 1024) "CAP_NET_BIND_SERVICE";
+        AmbientCapabilities = lib.optionalString (cfg.settings.listenport < 1024) "CAP_NET_BIND_SERVICE";
+        NoNewPrivileges = true;
+        PrivateTmp = true;
+        ProtectControlGroups = true;
+        ProtectHome = true;
+        ProtectKernelLogs = true;
+        ProtectKernelModules = true;
+        ProtectKernelTunables = true;
+        ProtectProc = "invisible";
+        ProtectSystem = "strict";
+        RestrictNamespaces = true;
+        RestrictRealtime = true;
+        SystemCallArchitectures = "native";
+        UMask = "0066";
+        SystemCallFilter = [
+          "@system-service"
+          "~@privileged"
+        ]
+        ++ lib.optional (cfg.settings ? tsdb) "mincore";
+        RestrictAddressFamilies = [
+          "AF_INET"
+          "AF_INET6"
+        ];
+        PrivateDevices = "yes";
+
+        ExecStart =
+          let
+            package = cfg.package.override { withThemes = cfg.extraThemes; };
+          in
+          ''${lib.getExe package} -c "''${CONFIGURATION_DIRECTORY}"/config.yaml -db "''${STATE_DIRECTORY}"/sqlite.db'';
+      };
+      enableStrictShellChecks = true;
+      startLimitIntervalSec = 10;
+      startLimitBurst = 3;
+      preStart = ''
+        cp "${configFile}" "''${RUNTIME_DIRECTORY}"/new
+        ${lib.getExe pkgs.jq} \
+            --arg jwt_secret "$(<"''${CREDENTIALS_DIRECTORY}"/jwt-secret)" \
+            --arg agent_secret "$(<"''${CREDENTIALS_DIRECTORY}"/agent-secret)" \
+            '. + { jwtsecretkey: $jwt_secret, agentsecretkey: $agent_secret }' \
+            < "''${RUNTIME_DIRECTORY}"/new > "''${RUNTIME_DIRECTORY}"/tmp
+        mv "''${RUNTIME_DIRECTORY}"/tmp "''${RUNTIME_DIRECTORY}"/new
+
+        ${lib.optionalString cfg.mutableConfig ''
+          [ -e "''${CONFIGURATION_DIRECTORY}"/config.yaml ] && \
+            ${lib.getExe pkgs.yj} < "''${CONFIGURATION_DIRECTORY}"/config.yaml > "''${RUNTIME_DIRECTORY}"/old && \
+            ${lib.getExe pkgs.jq} -s '.[0] * .[1]' \
+              "''${RUNTIME_DIRECTORY}"/old "''${RUNTIME_DIRECTORY}"/new > "''${RUNTIME_DIRECTORY}"/tmp
+          [ -e "''${RUNTIME_DIRECTORY}"/old ] && rm "''${RUNTIME_DIRECTORY}"/old
+          [ -e "''${RUNTIME_DIRECTORY}"/tmp ] && mv "''${RUNTIME_DIRECTORY}"/tmp "''${RUNTIME_DIRECTORY}"/new
+        ''}
+        mv "''${RUNTIME_DIRECTORY}"/new  "''${CONFIGURATION_DIRECTORY}"/config.yaml
+      '';
+      wantedBy = [ "multi-user.target" ];
+    };
+  };
+}