API

请求类型

POST

请求路径

/nacos/v1/ns/service

请求参数

错误编码

示例请求

curl -X POST '127.0.0.1:8848/nacos/v1/ns/service?serviceName=nacos.test.2&metadata=k1%3dv1'

示例返回

ok

关键流程源码解析

ServiceController

/** * Create a new service. * 新建一个服务 * @param namespaceId namespace id * @param serviceName service name * @param protectThreshold protect threshold * @param metadata service metadata * @param selector selector * @return 'ok' if success * @throws Exception exception */
    @PostMapping
    @Secured(parser = NamingResourceParser.class, action = ActionTypes.WRITE)
    public String create(@RequestParam(defaultValue = Constants.DEFAULT_NAMESPACE_ID) String namespaceId,
            @RequestParam String serviceName, @RequestParam(required = false, defaultValue = "0.0F") float protectThreshold,
            @RequestParam(defaultValue = StringUtils.EMPTY) String metadata,
            @RequestParam(defaultValue = StringUtils.EMPTY) String selector) throws Exception {
        //检测是服务是否已创建
        if (serviceManager.getService(namespaceId, serviceName) != null) {
            throw new IllegalArgumentException("specified service already exists, serviceName : " + serviceName);
        }

        Map<String, String> metadataMap = new HashMap<>(16);
        if (StringUtils.isNotBlank(metadata)) {
            metadataMap = UtilsAndCommons.parseMetadata(metadata);
        }

        Service service = new Service(serviceName);
        service.setProtectThreshold(protectThreshold);
        service.setEnabled(true);
        service.setMetadata(metadataMap);
        //设置服务路由类型，默认为None,
		//可以选择标签，并设置匹配规则 格式为：{"type": "label","expression": "CONSUMER.label.myLabel=PROVIDER.label.myLabel"}
        service.setSelector(parseSelector(selector));
        service.setNamespaceId(namespaceId);
        service.setLastModifiedMillis(System.currentTimeMillis());
        service.recalculateChecksum();
        //服务名称以及集群规范性检查
        service.validate();
        //更新服务信息
        serviceManager.addOrReplaceService(service);

        return "ok";
    }
    private Selector parseSelector(String selectorJsonString) throws Exception {
        //若传入的字符串为空，返回默认类型
        if (StringUtils.isBlank(selectorJsonString)) {
            return new NoneSelector();
        }
        //{type: "label", expression: "CONSUMER.label.site=PROVIDER.label.site"}
        JsonNode selectorJson = JacksonUtils.toObj(URLDecoder.decode(selectorJsonString, "UTF-8"));
        switch (SelectorType.valueOf(selectorJson.get("type").asText())) {
            case none:
                return new NoneSelector();
            case label:
                String expression = selectorJson.get("expression").asText();
				//转化表达式标签，必须以CONSUMER.label.形式开始
                Set<String> labels = LabelSelector.parseExpression(expression);
                LabelSelector labelSelector = new LabelSelector();
                labelSelector.setExpression(expression);
                labelSelector.setLabels(labels);
                return labelSelector;
            default:
                throw new NacosException(NacosException.INVALID_PARAM, "not match any type of selector!");
        }
    }

总结

创建服务需要留意的地方就是服务路由类型可以选择标签模式，当选择标签时表达式必须以 CONSUMER.label. 开头，实际的标签可以自定义。可以结合自己公司的CMDB资源管理在查询实例列表时可以获取与表达式匹配的机房节点，该策略Nacos本身并没有实现，需要用户自己实现CmdbService配置匹配规则。具体实现此处不做描述。后续会专门写一篇案例实现。