gistfile1.js

{config, pkgs, ...}:

with pkgs.lib;

let 
	cfg = config.services.zookeeper;
	custompkgs = import <customnixpkgs> {};
	zookeeper = custompkgs.zookeeper;
	zooCfg = pkgs.writeText "zoo.cfg" "${cfg.config}";
in

{
	options = {
		services.zookeeper = {
			
			enable = mkOption {
				default = false;
				description = "Wether to enable Zookeeper or not";
			};
			
			logDir = mkOption {
				description = "Where to keep Zookeeper log files.";
        		default = "/var/log/zookeeper";
        		type = types.path;
			};

			dataLogDir = mkOption {
				description = "the directory where transaction log is stored. This parameter provides dedicated log device for ZooKeeper";
				default = "/var/lib/zookeeper";
				type = types.string;
			};
			
			config = mkOption {
				default = ''
					# The number of milliseconds of each tick
					tickTime=2000
					
					# The number of ticks that the initial
					# synchronization phase can take
					initLimit=10
					
					# The number of ticks that can pass between
					# sending a request and getting an acknowledgement
					syncLimit=5
					
					# the directory where the snapshot is stored.
					# do not use /tmp for storage, /tmp here is just
					# example sakes.
					dataDir=/tmp/zookeeper/
			
					# the directory where transaction log is stored.
					# this parameter provides dedicated log device for ZooKeeper
					dataLogDir=${cfg.dataLogDir}
					
					# the port at which the clients will connect
					clientPort=2181
					
					# Be sure to read the maintenance section of the
					# administrator guide before turning on autopurge.
					#
					# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
					#
					# The number of snapshots to retain in dataDir
					#autopurge.snapRetainCount=3
					# Purge task interval in hours
					# Set to "0" to disable auto purge feature
					#autopurge.purgeInterval=1
				'';
				type = types.string;
				description = "Options to determine how Zookeeper works";
			};
			
			user = mkOption {
				default = "zookeeper";
				description = "User account under which Zookeeper runs.";
			};
		};
	};


	config = mkIf config.services.zookeeper.enable {

		users.extraGroups = optionalAttrs (cfg.user == "zookeeper") (singleton
	    {
	        name = "zookeeper";
	    });

	    users.extraUsers = optionalAttrs (cfg.user == "zookeeper") (singleton
	    {	name = "zookeeper";
	     	group = "zookeeper";
	     	isSystemUser = true;
	     	description = "Zookeeper user";
	     	home = "/var/lib/zookeeper";
	     	createHome = true;
	    });

		systemd.services.zookeeper = {
			description = "Zookeeper daemon";
			wantedBy = ["multi-user.target"];
			
			preStart = ''
				mkdir -p ${cfg.logDir}
			'';

			serviceConfig = 
			{	WorkingDirectory = cfg.dataLogDir;
				ExecStart = "${pkgs.jre}/bin/java -Dzookeeper.log.dir=${cfg.logDir} -cp ${zookeeper}/lib/*:${zookeeper}/zookeeper.jar:${zookeeper}/conf -Dcom.sun.management.jmxremote -Dcom.sun.management.jmxremote.local.only=false org.apache.zookeeper.server.quorum.QuorumPeerMain ${zooCfg}";
				User = cfg.user;
				PermissionsStartOnly = true;
				Group = cfg.user;
				Restart = "always";
			};
		};
	};
}