order

This paper mainly studies the remote Instance of Nacos Service Manager.

ServiceManager

nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/core/ServiceManager.java

@Component
@DependsOn("nacosApplicationContext")
public class ServiceManager implements RecordListener<Service> {

    /**
     * Map<namespace, Map<group::serviceName, Service>>
     */
    private Map<String, Map<String, Service>> serviceMap = new ConcurrentHashMap<>();

    private LinkedBlockingDeque<ServiceKey> toBeUpdatedServicesQueue = new LinkedBlockingDeque<>(1024 * 1024);

    private Synchronizer synchronizer = new ServiceStatusSynchronizer();

    private final Lock lock = new ReentrantLock();

    @Resource(name = "consistencyDelegate")
    private ConsistencyService consistencyService;

    @Autowired
    private SwitchDomain switchDomain;

    @Autowired
    private DistroMapper distroMapper;

    @Autowired
    private ServerListManager serverListManager;

    @Autowired
    private PushService pushService;

    private final Object putServiceLock = new Object();

    //......

    public void removeInstance(String namespaceId, String serviceName, boolean ephemeral, Instance... ips) throws NacosException {
        Service service = getService(namespaceId, serviceName);
        removeInstance(namespaceId, serviceName, ephemeral, service, ips);
    }

    public void removeInstance(String namespaceId, String serviceName, boolean ephemeral, Service service, Instance... ips) throws NacosException {

        String key = KeyBuilder.buildInstanceListKey(namespaceId, serviceName, ephemeral);

        List<Instance> instanceList = substractIpAddresses(service, ephemeral, ips);

        Instances instances = new Instances();
        instances.setInstanceList(instanceList);

        consistencyService.put(key, instances);
    }

    public List<Instance> substractIpAddresses(Service service, boolean ephemeral, Instance... ips) throws NacosException {
        return updateIpAddresses(service, UtilsAndCommons.UPDATE_INSTANCE_ACTION_REMOVE, ephemeral, ips);
    }

    public List<Instance> updateIpAddresses(Service service, String action, boolean ephemeral, Instance... ips) throws NacosException {

        Datum datum = consistencyService.get(KeyBuilder.buildInstanceListKey(service.getNamespaceId(), service.getName(), ephemeral));

        Map<String, Instance> oldInstanceMap = new HashMap<>(16);
        List<Instance> currentIPs = service.allIPs(ephemeral);
        Map<String, Instance> map = new ConcurrentHashMap<>(currentIPs.size());

        for (Instance instance : currentIPs) {
            map.put(instance.toIPAddr(), instance);
        }
        if (datum != null) {
            oldInstanceMap = setValid(((Instances) datum.value).getInstanceList(), map);
        }

        // use HashMap for deep copy:
        HashMap<String, Instance> instanceMap = new HashMap<>(oldInstanceMap.size());
        instanceMap.putAll(oldInstanceMap);

        for (Instance instance : ips) {
            if (!service.getClusterMap().containsKey(instance.getClusterName())) {
                Cluster cluster = new Cluster(instance.getClusterName(), service);
                cluster.init();
                service.getClusterMap().put(instance.getClusterName(), cluster);
                Loggers.SRV_LOG.warn("cluster: {} not found, ip: {}, will create new cluster with default configuration.",
                    instance.getClusterName(), instance.toJSON());
            }

            if (UtilsAndCommons.UPDATE_INSTANCE_ACTION_REMOVE.equals(action)) {
                instanceMap.remove(instance.getDatumKey());
            } else {
                instanceMap.put(instance.getDatumKey(), instance);
            }

        }

        if (instanceMap.size() <= 0 && UtilsAndCommons.UPDATE_INSTANCE_ACTION_ADD.equals(action)) {
            throw new IllegalArgumentException("ip list can not be empty, service: " + service.getName() + ", ip list: "
                + JSON.toJSONString(instanceMap.values()));
        }

        return new ArrayList<>(instanceMap.values());
    }

    //......
}

• The removeInstance method obtains the instanceList after removing instances by substractIpAddresses, and then updates it by consistency Service. put method; the substractIpAddresses method executes the updateIpAddresses method, whose action parameter value is Utils AndCommons. UPDATE_INSTANCE_ACTION_remove. It first obtains the instance list by using service.allIPs(ephemeral) for remotely. The ve action removes it from the instanceMap based on instance.getDatumKey().

Service.allIPs

nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/core/Service.java

public class Service extends com.alibaba.nacos.api.naming.pojo.Service implements Record, RecordListener<Instances> {

    private static final String SERVICE_NAME_SYNTAX = "[0-9a-zA-Z@\\.:_-]+";

    @JSONField(serialize = false)
    private ClientBeatCheckTask clientBeatCheckTask = new ClientBeatCheckTask(this);

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

    /**
     * IP will be deleted if it has not send beat for some time, default timeout is 30 seconds.
     */
    private long ipDeleteTimeout = 30 * 1000;

    private volatile long lastModifiedMillis = 0L;

    private volatile String checksum;

    /**
     * TODO set customized push expire time:
     */
    private long pushCacheMillis = 0L;

    private Map<String, Cluster> clusterMap = new HashMap<>();

    //......

    public List<Instance> allIPs(boolean ephemeral) {
        List<Instance> allIPs = new ArrayList<>();
        for (Map.Entry<String, Cluster> entry : clusterMap.entrySet()) {
            allIPs.addAll(entry.getValue().allIPs(ephemeral));
        }

        return allIPs;
    }

    //......
}

• The Service's allIPs method traverses the clusterMap and then collects Instance through Cluster.allIPs(ephemeral)

Cluster.allIPs

nacos-1.1.3/naming/src/main/java/com/alibaba/nacos/naming/core/Cluster.java

public class Cluster extends com.alibaba.nacos.api.naming.pojo.Cluster implements Cloneable {

    private static final String CLUSTER_NAME_SYNTAX = "[0-9a-zA-Z-]+";
    /**
     * a addition for same site routing, can group multiple sites into a region, like Hangzhou, Shanghai, etc.
     */
    private String sitegroup = StringUtils.EMPTY;

    private int defCkport = 80;

    private int defIPPort = -1;

    @JSONField(serialize = false)
    private HealthCheckTask checkTask;

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

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

    @JSONField(serialize = false)
    private Service service;

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

    private Map<String, String> metadata = new ConcurrentHashMap<>();

    //......

    public List<Instance> allIPs(boolean ephemeral) {
        return ephemeral ? new ArrayList<>(ephemeralInstances) : new ArrayList<>(persistentInstances);
    }

    //......
}

• Cluster's allIPs method returns ephemeral Instances or persistent Instances based on ephemeral

Summary

The removeInstance method of Service Manager obtains instanceList after removing instances by substractIpAddresses, and then updates it by consistencyService.put method; the substractIpAddresses method executes updateIpAddresses method, whose action parameter value is Utils AndCommons. UPDATE_INSTANCE_ACTION_REMOVE, which first obtains instances using service.allIPs(ephemeral) List, which is removed from the instanceMap according to instance.getDatumKey() for remove action

doc

• ServiceManager