nacos注册中心之服务地址的查询

nacos注册中心之服务地址的查询

Open API：

get请求

http://127.0.0.1:848/nacos/v1/ns/instance/list?serviceName=example

对应InstanceController的list方法：

@GetMapping("/list")
public JSONObject list(HttpServletRequest request) throws Exception {

    String namespaceId = WebUtils.optional(request, CommonParams.NAMESPACE_ID,
        Constants.DEFAULT_NAMESPACE_ID);

    String serviceName = WebUtils.required(request, CommonParams.SERVICE_NAME);
    String agent = WebUtils.getUserAgent(request);
    String clusters = WebUtils.optional(request, "clusters", StringUtils.EMPTY);
    String clientIP = WebUtils.optional(request, "clientIP", StringUtils.EMPTY);
    Integer udpPort = Integer.parseInt(WebUtils.optional(request, "udpPort", "0"));
    String env = WebUtils.optional(request, "env", StringUtils.EMPTY);
    boolean isCheck = Boolean.parseBoolean(WebUtils.optional(request, "isCheck", "false"));

    String app = WebUtils.optional(request, "app", StringUtils.EMPTY);

    String tenant = WebUtils.optional(request, "tid", StringUtils.EMPTY);

    boolean healthyOnly = Boolean.parseBoolean(WebUtils.optional(request, "healthyOnly", "false"));

    return doSrvIPXT(namespaceId, serviceName, agent, clusters, clientIP, udpPort, env, isCheck, app, tenant,
        healthyOnly);
}

1. 解析请求参数
2. 通过doSrvIPXT方法返回服务列表数据

doSrvIPXT方法：

public JSONObject doSrvIPXT(String namespaceId, String serviceName, String agent, String clusters, String clientIP,
                            int udpPort,
                            String env, boolean isCheck, String app, String tid, boolean healthyOnly)
    throws Exception {

    ClientInfo clientInfo = new ClientInfo(agent);
    JSONObject result = new JSONObject();
    Service service = serviceManager.getService(namespaceId, serviceName);

    if (service == null) {
        if (Loggers.SRV_LOG.isDebugEnabled()) {
            Loggers.SRV_LOG.debug("no instance to serve for service: {}", serviceName);
        }
        result.put("name", serviceName);
        result.put("clusters", clusters);
        result.put("hosts", new JSONArray());
        return result;
    }

    checkIfDisabled(service);

    long cacheMillis = switchDomain.getDefaultCacheMillis();

    // now try to enable the push
    try {
        if (udpPort > 0 && pushService.canEnablePush(agent)) {
            pushService.addClient(namespaceId, serviceName,
                clusters,
                agent,
                new InetSocketAddress(clientIP, udpPort),
                pushDataSource,
                tid,
                app);
            cacheMillis = switchDomain.getPushCacheMillis(serviceName);
        }
    } catch (Exception e) {
        Loggers.SRV_LOG.error("[NACOS-API] failed to added push client", e);
        cacheMillis = switchDomain.getDefaultCacheMillis();
    }

    List<Instance> srvedIPs;

    srvedIPs = service.srvIPs(Arrays.asList(StringUtils.split(clusters, ",")));

    // filter ips using selector:
    if (service.getSelector() != null && StringUtils.isNotBlank(clientIP)) {
        srvedIPs = service.getSelector().select(clientIP, srvedIPs);
    }

    if (CollectionUtils.isEmpty(srvedIPs)) {

        if (Loggers.SRV_LOG.isDebugEnabled()) {
            Loggers.SRV_LOG.debug("no instance to serve for service: {}", serviceName);
        }

        if (clientInfo.type == ClientInfo.ClientType.JAVA &&
            clientInfo.version.compareTo(VersionUtil.parseVersion("1.0.0")) >= 0) {
            result.put("dom", serviceName);
        } else {
            result.put("dom", NamingUtils.getServiceName(serviceName));
        }

        result.put("hosts", new JSONArray());
        result.put("name", serviceName);
        result.put("cacheMillis", cacheMillis);
        result.put("lastRefTime", System.currentTimeMillis());
        result.put("checksum", service.getChecksum());
        result.put("useSpecifiedURL", false);
        result.put("clusters", clusters);
        result.put("env", env);
        result.put("metadata", service.getMetadata());
        return result;
    }

    Map<Boolean, List<Instance>> ipMap = new HashMap<>(2);
    ipMap.put(Boolean.TRUE, new ArrayList<>());
    ipMap.put(Boolean.FALSE, new ArrayList<>());

    for (Instance ip : srvedIPs) {
        ipMap.get(ip.isHealthy()).add(ip);
    }

    if (isCheck) {
        result.put("reachProtectThreshold", false);
    }

    double threshold = service.getProtectThreshold();

    if ((float) ipMap.get(Boolean.TRUE).size() / srvedIPs.size() <= threshold) {

        Loggers.SRV_LOG.warn("protect threshold reached, return all ips, service: {}", serviceName);
        if (isCheck) {
            result.put("reachProtectThreshold", true);
        }

        ipMap.get(Boolean.TRUE).addAll(ipMap.get(Boolean.FALSE));
        ipMap.get(Boolean.FALSE).clear();
    }

    if (isCheck) {
        result.put("protectThreshold", service.getProtectThreshold());
        result.put("reachLocalSiteCallThreshold", false);

        return new JSONObject();
    }

    JSONArray hosts = new JSONArray();

    for (Map.Entry<Boolean, List<Instance>> entry : ipMap.entrySet()) {
        List<Instance> ips = entry.getValue();

        if (healthyOnly && !entry.getKey()) {
            continue;
        }

        for (Instance instance : ips) {

            // remove disabled instance:
            if (!instance.isEnabled()) {
                continue;
            }

            JSONObject ipObj = new JSONObject();

            ipObj.put("ip", instance.getIp());
            ipObj.put("port", instance.getPort());
            // deprecated since nacos 1.0.0:
            ipObj.put("valid", entry.getKey());
            ipObj.put("healthy", entry.getKey());
            ipObj.put("marked", instance.isMarked());
            ipObj.put("instanceId", instance.getInstanceId());
            ipObj.put("metadata", instance.getMetadata());
            ipObj.put("enabled", instance.isEnabled());
            ipObj.put("weight", instance.getWeight());
            ipObj.put("clusterName", instance.getClusterName());
            if (clientInfo.type == ClientInfo.ClientType.JAVA &&
                clientInfo.version.compareTo(VersionUtil.parseVersion("1.0.0")) >= 0) {
                ipObj.put("serviceName", instance.getServiceName());
            } else {
                ipObj.put("serviceName", NamingUtils.getServiceName(instance.getServiceName()));
            }

            ipObj.put("ephemeral", instance.isEphemeral());
            hosts.add(ipObj);

        }
    }

    result.put("hosts", hosts);
    if (clientInfo.type == ClientInfo.ClientType.JAVA &&
        clientInfo.version.compareTo(VersionUtil.parseVersion("1.0.0")) >= 0) {
        result.put("dom", serviceName);
    } else {
        result.put("dom", NamingUtils.getServiceName(serviceName));
    }
    result.put("name", serviceName);
    result.put("cacheMillis", cacheMillis);
    result.put("lastRefTime", System.currentTimeMillis());
    result.put("checksum", service.getChecksum());
    result.put("useSpecifiedURL", false);
    result.put("clusters", clusters);
    result.put("env", env);
    result.put("metadata", service.getMetadata());
    return result;
}

1. 根据namespaceId serviceName获得Service实例。
2. 从Service实例中调用srvIPs方法得到所有服务提供者的实例信息。
3. 遍历组装JSON字符串并返回。

这就是nacos的服务查询功能呢，对应接口就是这个

get请求

http://127.0.0.1:848/nacos/v1/ns/instance/list?serviceName=example

深入源码，了解它的本质，让我们一起学习，一起进步吧~