5.nacos启动之-注册表中核心内存数据结构

注册中心的注册功能核心数据结构都在com.alibaba.nacos.naming.core包下，主要由servicemanager，service，cluster，instance几个概念组成。并且由serviceManager来管理，首先来看ServiceManager类，该类持有一个ConcurrentHashMap>类型的serviceMap：

private Map> serviceMap = new ConcurrentHashMap<>();

这个map就是注册中心核心数据结构了。该map的key是个namespace，value是个Map，该map的key是group::serviceName，value是个service类。

对于service类，核心的属性有下面几个：

private String token;
private List owners = new ArrayList<>();
private Boolean resetWeight = false;
private Boolean enabled = true;
private Selector selector = new NoneSelector();
private String namespaceId;
private Map clusterMap = new HashMap();

注册相关的核心数据结构就是clusterMap了，key是个string，保存的是clustername，value是个Cluster类型。来看cluster类，核心数据结构是两个Set。

@JSONField(serialize = false)
private Set persistentInstances = new HashSet<>();

@JSONField(serialize = false)
private Set ephemeralInstances = new HashSet<>();

第一个是持久化类型，该类型会被持久化处理，第二个是暂时的类型，默认的服务都是这种类型，放在内存中。最后来看instance，instance本身定义的属性不多：

private static final double MAX_WEIGHT_VALUE = 10000.0D;
private static final double MIN_POSTIVE_WEIGHT_VALUE = 0.01D;
private static final double MIN_WEIGHT_VALUE = 0.00D;

private volatile long lastBeat = System.currentTimeMillis();

@JSONField(serialize = false)
private volatile boolean mockValid = false;

private volatile boolean marked = false;

private String tenant;

private String app;

public static final Pattern IP_PATTERN
    = Pattern.compile("(\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}\\.\\d{1,3}):?(\\d{1,5})?");

public static final String SPLITER = "_";

多数都是无关紧要的属性，核心属性定义在父类中：

/**
 * unique id of this instance.
 */
private String instanceId;

/**
 * instance ip
 */
private String ip;

/**
 * instance port
 */
private int port;

/**
 * instance weight
 */
private double weight = 1.0D;

/**
 * instance health status
 */
private boolean healthy = true;

/**
 * If instance is enabled to accept request
 */
private boolean enabled = true;

/**
 * If instance is ephemeral
 *
 * @since 1.0.0
 */
private boolean ephemeral = true;

/**
 * cluster information of instance
 */
private String clusterName;

/**
 * Service information of instance
 */
private String serviceName;

/**
 * user extended attributes
 */
private Map metadata = new HashMap();

总结起来就是：

instance属性；

private String instanceId;

private String ip;

private int port;

private double weight = 1.0D;//权重

private boolean healthy = true;//健康状态

private boolean enabled = true;

private boolean ephemeral = true;

private String clusterName;

private String serviceName;

private Map metadata = new HashMap();

private volatile long lastBeat = System.currentTimeMillis();

cluster：

ephemeralInstances :HashSet

service:

clusterMap:Map

serviceManager:

serviceMap:Map>