nixos/zabbixProxy: init module

nixos/modules/module-list.nix

@@ -516,6 +516,7 @@
   ./services/monitoring/uptime.nix
   ./services/monitoring/vnstat.nix
   ./services/monitoring/zabbix-agent.nix
+  ./services/monitoring/zabbix-proxy.nix
   ./services/monitoring/zabbix-server.nix
   ./services/network-filesystems/beegfs.nix
   ./services/network-filesystems/cachefilesd.nix

nixos/modules/services/monitoring/zabbix-proxy.nix

@@ -0,0 +1,290 @@
+{ config, lib, pkgs, ... }:
+
+let
+  cfg = config.services.zabbixProxy;
+  pgsql = config.services.postgresql;
+  mysql = config.services.mysql;
+
+  inherit (lib) mkDefault mkEnableOption mkIf mkOption;
+  inherit (lib) attrValues concatMapStringsSep literalExample optional optionalAttrs optionalString types;
+
+  user = "zabbix";
+  group = "zabbix";
+  runtimeDir = "/run/zabbix";
+  stateDir = "/var/lib/zabbix";
+  passwordFile = "${runtimeDir}/zabbix-dbpassword.conf";
+
+  moduleEnv = pkgs.symlinkJoin {
+    name = "zabbix-proxy-module-env";
+    paths = attrValues cfg.modules;
+  };
+
+  configFile = pkgs.writeText "zabbix_proxy.conf" ''
+    LogType = console
+    ListenIP = ${cfg.listen.ip}
+    ListenPort = ${toString cfg.listen.port}
+    # TODO: set to cfg.database.socket if database type is pgsql?
+    DBHost = ${optionalString (cfg.database.createLocally != true) cfg.database.host}
+    ${optionalString (cfg.database.createLocally != true) "DBPort = ${cfg.database.port}"}
+    DBName = ${cfg.database.name}
+    DBUser = ${cfg.database.user}
+    ${optionalString (cfg.database.passwordFile != null) "Include ${passwordFile}"}
+    ${optionalString (mysqlLocal && cfg.database.socket != null) "DBSocket = ${cfg.database.socket}"}
+    SocketDir = ${runtimeDir}
+    FpingLocation = /run/wrappers/bin/fping
+    ${optionalString (cfg.modules != {}) "LoadModulePath = ${moduleEnv}/lib"}
+    ${concatMapStringsSep "\n" (name: "LoadModule = ${name}") (builtins.attrNames cfg.modules)}
+    ${cfg.extraConfig}
+  '';
+
+  mysqlLocal = cfg.database.createLocally && cfg.database.type == "mysql";
+  pgsqlLocal = cfg.database.createLocally && cfg.database.type == "pgsql";
+
+in
+
+{
+  # interface
+
+  options = {
+
+    services.zabbixProxy = {
+      enable = mkEnableOption "the Zabbix Proxy";
+
+      package = mkOption {
+        type = types.package;
+        default =
+          if cfg.database.type == "mysql" then pkgs.zabbix.proxy-mysql
+          else if cfg.database.type == "pgsql" then pkgs.zabbix.proxy-pgsql
+          else pkgs.zabbix.proxy-sqlite;
+        defaultText = "pkgs.zabbix.proxy-pgsql";
+        description = "The Zabbix package to use.";
+      };
+
+      extraPackages = mkOption {
+        type = types.listOf types.package;
+        default = with pkgs; [ nettools nmap traceroute ];
+        defaultText = "[ nettools nmap traceroute ]";
+        description = ''
+          Packages to be added to the Zabbix <envar>PATH</envar>.
+          Typically used to add executables for scripts, but can be anything.
+        '';
+      };
+
+      modules = mkOption {
+        type = types.attrsOf types.package;
+        description = "A set of modules to load.";
+        default = {};
+        example = literalExample ''
+          {
+            "dummy.so" = pkgs.stdenv.mkDerivation {
+              name = "zabbix-dummy-module-''${cfg.package.version}";
+              src = cfg.package.src;
+              buildInputs = [ cfg.package ];
+              sourceRoot = "zabbix-''${cfg.package.version}/src/modules/dummy";
+              installPhase = '''
+                mkdir -p $out/lib
+                cp dummy.so $out/lib/
+              ''';
+            };
+          }
+        '';
+      };
+
+      database = {
+        type = mkOption {
+          type = types.enum [ "mysql" "pgsql" "sqlite" ];
+          example = "mysql";
+          default = "pgsql";
+          description = "Database engine to use.";
+        };
+
+        host = mkOption {
+          type = types.str;
+          default = "localhost";
+          description = "Database host address.";
+        };
+
+        port = mkOption {
+          type = types.int;
+          default = if cfg.database.type == "mysql" then mysql.port else pgsql.port;
+          description = "Database host port.";
+        };
+
+        name = mkOption {
+          type = types.str;
+          default = "zabbix";
+          description = "Database name.";
+        };
+
+        user = mkOption {
+          type = types.str;
+          default = "zabbix";
+          description = "Database user.";
+        };
+
+        passwordFile = mkOption {
+          type = types.nullOr types.path;
+          default = null;
+          example = "/run/keys/zabbix-dbpassword";
+          description = ''
+            A file containing the password corresponding to
+            <option>database.user</option>.
+          '';
+        };
+
+        socket = mkOption {
+          type = types.nullOr types.path;
+          default = null;
+          example = "/run/postgresql";
+          description = "Path to the unix socket file to use for authentication.";
+        };
+
+        createLocally = mkOption {
+          type = types.bool;
+          default = true;
+          description = "Whether to create a local database automatically.";
+        };
+      };
+
+      listen = {
+        ip = mkOption {
+          type = types.str;
+          default = "0.0.0.0";
+          description = ''
+            List of comma delimited IP addresses that the trapper should listen on.
+            Trapper will listen on all network interfaces if this parameter is missing.
+          '';
+        };
+
+        port = mkOption {
+          type = types.port;
+          default = 10051;
+          description = ''
+            Listen port for trapper.
+          '';
+        };
+      };
+
+      openFirewall = mkOption {
+        type = types.bool;
+        default = false;
+        description = ''
+          Open ports in the firewall for the Zabbix Proxy.
+        '';
+      };
+
+      # TODO: for bonus points migrate this to https://github.com/NixOS/rfcs/pull/42
+      extraConfig = mkOption {
+        default = "";
+        type = types.lines;
+        description = ''
+          Configuration that is injected verbatim into the configuration file. Refer to
+          <link xlink:href="https://www.zabbix.com/documentation/current/manual/appendix/config/zabbix_proxy"/>
+          for details on supported values.
+        '';
+      };
+
+    };
+
+  };
+
+  # implementation
+
+  config = mkIf cfg.enable {
+
+    assertions = [
+      { assertion = !config.services.zabbixServer.enable;
+        message = "Please choose one of services.zabbixServer or services.zabbixProxy.";
+      }
+      { assertion = cfg.database.createLocally -> cfg.database.user == user;
+        message = "services.zabbixProxy.database.user must be set to ${user} if services.zabbixProxy.database.createLocally is set true";
+      }
+      { assertion = cfg.database.createLocally -> cfg.database.passwordFile == null;
+        message = "a password cannot be specified if services.zabbixProxy.database.createLocally is set to true";
+      }
+    ];
+
+    networking.firewall = mkIf cfg.openFirewall {
+      allowedTCPPorts = [ cfg.listen.port ];
+    };
+
+    services.mysql = optionalAttrs mysqlLocal {
+      enable = true;
+      package = mkDefault pkgs.mariadb;
+      ensureDatabases = [ cfg.database.name ];
+      ensureUsers = [
+        { name = cfg.database.user;
+          ensurePermissions = { "${cfg.database.name}.*" = "ALL PRIVILEGES"; };
+        }
+      ];
+    };
+
+    services.postgresql = optionalAttrs pgsqlLocal {
+      enable = true;
+      ensureDatabases = [ cfg.database.name ];
+      ensureUsers = [
+        { name = cfg.database.user;
+          ensurePermissions = { "DATABASE ${cfg.database.name}" = "ALL PRIVILEGES"; };
+        }
+      ];
+    };
+
+    users.users.${user} = {
+      description = "Zabbix daemon user";
+      uid = config.ids.uids.zabbix;
+      inherit group;
+    };
+
+    users.groups.${group} = {
+      gid = config.ids.gids.zabbix;
+    };
+
+    security.wrappers = {
+      fping.source = "${pkgs.fping}/bin/fping";
+    };
+
+    systemd.services."zabbix-proxy" = {
+      description = "Zabbix Proxy";
+
+      wantedBy = [ "multi-user.target" ];
+      after = optional mysqlLocal "mysql.service" ++ optional pgsqlLocal "postgresql.service";
+
+      path = [ "/run/wrappers" ] ++ cfg.extraPackages;
+      preStart = optionalString pgsqlLocal ''
+        if ! test -e "${stateDir}/db-created"; then
+          cat ${cfg.package}/share/zabbix/database/postgresql/schema.sql | ${pgsql.package}/bin/psql ${cfg.database.name}
+          cat ${cfg.package}/share/zabbix/database/postgresql/images.sql | ${pgsql.package}/bin/psql ${cfg.database.name}
+          cat ${cfg.package}/share/zabbix/database/postgresql/data.sql | ${pgsql.package}/bin/psql ${cfg.database.name}
+          touch "${stateDir}/db-created"
+        fi
+      '' + optionalString mysqlLocal ''
+        if ! test -e "${stateDir}/db-created"; then
+          cat ${cfg.package}/share/zabbix/database/mysql/schema.sql | ${mysql.package}/bin/mysql ${cfg.database.name}
+          cat ${cfg.package}/share/zabbix/database/mysql/images.sql | ${mysql.package}/bin/mysql ${cfg.database.name}
+          cat ${cfg.package}/share/zabbix/database/mysql/data.sql | ${mysql.package}/bin/mysql ${cfg.database.name}
+          touch "${stateDir}/db-created"
+        fi
+      '' + optionalString (cfg.database.passwordFile != null) ''
+        # create a copy of the supplied password file in a format zabbix can consume
+        touch ${passwordFile}
+        chmod 0600 ${passwordFile}
+        echo -n "DBPassword = " > ${passwordFile}
+        cat ${cfg.database.passwordFile} >> ${passwordFile}
+      '';
+
+      serviceConfig = {
+        ExecStart = "@${cfg.package}/sbin/zabbix_proxy zabbix_proxy -f --config ${configFile}";
+        Restart = "always";
+        RestartSec = 2;
+
+        User = user;
+        Group = group;
+        RuntimeDirectory = "zabbix";
+        StateDirectory = "zabbix";
+        PrivateTmp = true;
+      };
+    };
+
+  };
+
+}