nacos 默认 namespace: public 拿不到数据

nacos 是阿里开源的配置中心/注册中心组件

在spring-boot项目中, 可以使用下面的方法启动nacos config

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nacos:
config:
# 使用namespace=public时, 这里不能显示指定. 否则会拿不到数据
# namespace: public
username: admin
password: 12345678
server-addr: 10.0.18.92:8848
group: ${spring.profiles.active}
# common 放通用配置, 可以被${spring.application.name}覆盖
data-ids: ${spring.application.name},common
type: YAML
auto-refresh: true
remote-first: true
enable-remote-sync-config: true
config-long-poll-timeout: 45000
max-retry: 10
config-retry-time: 3500
bootstrap:
# 开启log
enable: true
log-enable: true

最坑的就是这个

1	namespace: public

public是系统默认的namespace

但是不能在这里制定, 否则会造成nacos客户端向nacos server拿不到config的情况.

这是nacos的一个bug(可以说是命名不规范吧), 具体可以参考其源码

com.alibaba.nacos.client.config.impl.ClientWorker#getServerConfig

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public String[] getServerConfig(String dataId, String group, String tenant, long readTimeout)
throws NacosException {
String[] ct = new String[2];
if (StringUtils.isBlank(group)) {
group = Constants.DEFAULT_GROUP;
}

HttpRestResult<String> result = null;
try {
Map<String, String> params = new HashMap<String, String>(3);
if (StringUtils.isBlank(tenant)) {
params.put("dataId", dataId);
params.put("group", group);
} else {
params.put("dataId", dataId);
params.put("group", group);
params.put("tenant", tenant);
}
result = agent.httpGet(Constants.CONFIG_CONTROLLER_PATH, null, params, agent.getEncode(), readTimeout);
} catch (Exception ex) {
String message = String
.format("[%s] [sub-server] get server config exception, dataId=%s, group=%s, tenant=%s",
agent.getName(), dataId, group, tenant);
LOGGER.error(message, ex);
throw new NacosException(NacosException.SERVER_ERROR, ex);
}

代码中 tenant 就是namespace, 当不指定时, params 里面没有 tenant 项, 只有在指定了namespace时才会有这个请求参数

下面看server端实现

com.alibaba.nacos.config.server.service.repository.extrnal.ExternalStoragePersistServiceImpl#findConfigInfo(java.lang.String, java.lang.String, java.lang.String)

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@Override
public ConfigInfo findConfigInfo(final String dataId, final String group, final String tenant) {
final String tenantTmp = StringUtils.isBlank(tenant) ? StringUtils.EMPTY : tenant;
try {
return this.jt.queryForObject(
"SELECT ID,data_id,group_id,tenant_id,app_name,content,md5,type FROM config_info WHERE data_id=? AND group_id=? AND tenant_id=?",
new Object[] {dataId, group, tenantTmp}, CONFIG_INFO_ROW_MAPPER);
} catch (EmptyResultDataAccessException e) { // Indicates that the data does not exist, returns null.
return null;
} catch (CannotGetJdbcConnectionException e) {
LogUtil.FATAL_LOG.error("[db-error] " + e.toString(), e);
throw e;
}
}

到这里就成了 tenant_id

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/**
* Execute clone config operation.
*
* @param request http servlet request .
* @param srcUser src user string value.
* @param namespace namespace string value.
* @param configBeansList config beans list.
* @param policy config policy model.
* @return RestResult for map.
* @throws NacosException NacosException.
*/
@PostMapping(params = "clone=true")
@Secured(action = ActionTypes.WRITE, parser = ConfigResourceParser.class)
public RestResult<Map<String, Object>> cloneConfig(HttpServletRequest request,
@RequestParam(value = "src_user", required = false) String srcUser,
@RequestParam(value = "tenant", required = true) String namespace,
@RequestBody(required = true) List<SameNamespaceCloneConfigBean> configBeansList,
@RequestParam(value = "policy", defaultValue = "ABORT") SameConfigPolicy policy) throws NacosException {
Map<String, Object> failedData = new HashMap<>(4);
if (CollectionUtils.isEmpty(configBeansList)) {
failedData.put("succCount", 0);
return ResultBuilder.buildResult(ResultCodeEnum.NO_SELECTED_CONFIG, failedData);
}
configBeansList.removeAll(Collections.singleton(null));

if (NAMESPACE_PUBLIC_KEY.equalsIgnoreCase(namespace)) {
namespace = "";
} else if (persistService.tenantInfoCountByTenantId(namespace) <= 0) {
failedData.put("succCount", 0);
return ResultBuilder.buildResult(ResultCodeEnum.NAMESPACE_NOT_EXIST, failedData);
}

List<Long> idList = new ArrayList<>(configBeansList.size());
Map<Long, SameNamespaceCloneConfigBean> configBeansMap = configBeansList.stream()
.collect(Collectors.toMap(SameNamespaceCloneConfigBean::getCfgId, cfg -> {
idList.add(cfg.getCfgId());
return cfg;
}, (k1, k2) -> k1));

诡异的代码出现了

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if (NAMESPACE_PUBLIC_KEY.equalsIgnoreCase(namespace)) {
namespace = "";
} else if (persistService.tenantInfoCountByTenantId(namespace) <= 0) {
failedData.put("succCount", 0);
return ResultBuilder.buildResult(ResultCodeEnum.NAMESPACE_NOT_EXIST, failedData);
}

添加配置时, 如果namespace为public时, 最终存入数据的 tenant_id 为 StringUtils.EMPTY

获取的时候是没有这个潜规则的

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所以, 当我们在客户端指定 namespace = public 时, 就死活拿不到数据了.

其中 namespace -> tenant -> tenant_id -> namespaceId 其实一直扮演着一个角色(即: 命名空间)

在这里提两点意见

1. 既然自己制定了规则, 那就要把规则落地. 不然就必定会有人为此躺坑.

2. 所谓名不正言不顺, 同一个东西在项目中尽量不要起多个名字.