NacosFactory (獲取工廠的統(tǒng)一入口)

// 通過(guò)配置類獲取?ConfigService

public static ConfigService createConfigService(Properties properties) throws NacosException {

????return ConfigFactory.createConfigService(properties);

}

// 通過(guò)服務(wù)端地址獲取?ConfigService

public static ConfigService createConfigService(String serverAddr) throws NacosException {?

? ?return ConfigFactory.createConfigService(serverAddr);

}

com.alibaba.nacos.api.NacosFactory 工廠類?

提供獲取ConfigFactory晌坤、NamingFactory厨诸、NamingMaintainFactory工廠的靜態(tài)方法。

設(shè)計(jì)模式：典型的 工廠模式 應(yīng)用

ConfigService （分布式配置接口）

ConfigService UML

// 根據(jù)dataid自赔、group獲取配置信息

String getConfig(String dataId, String group, long timeoutMs) throws NacosException;

String getConfigAndSignListener(String dataId, String group, long timeoutMs, Listener listener) throws NacosException;

// 針對(duì)dataid、group增加監(jiān)聽(tīng)器

void addListener(String dataId, String group, Listener listener) throws NacosException;

// 發(fā)布配置

boolean publishConfig(String dataId, String group, String content) throws NacosException;

// 刪除配置

boolean removeConfig(String dataId, String group) throws NacosException;

// 刪除監(jiān)聽(tīng)器

void removeListener(String dataId, String group, Listener listener);

// 服務(wù)狀態(tài)

String getServerStatus();

// 關(guān)閉回收狀態(tài)

void shutDown() throws NacosException;

com.alibaba.nacos.api.config.ConfigService?

提供了一些針對(duì)配置的CRUD操作以及監(jiān)聽(tīng)配置的變更的能力

NacosConfigService (分布式配置接口實(shí)現(xiàn))

// http 代理類 根據(jù)名字就可以知道這個(gè)主要用于http協(xié)議對(duì)外交互

private final HttpAgent agent;

// long polling?

private final ClientWorker worker;

private String namespace;

// 關(guān)于配置的過(guò)濾器管理類?

private final ConfigFilterChainManager configFilterChainManager = new ConfigFilterChainManager();

NacosConfigService

HttpAgent (http 代理類)

HttpAgent UML

void start() throws NacosException;

HttpRestResult<String> httpGet(String path, Map<String, String> headers, Map<String, String> paramValues, String encoding, long readTimeoutMs) throws Exception;

HttpRestResult<String> httpPost(String path, Map<String, String> headers, Map<String, String> paramValues, String encoding, long readTimeoutMs) throws Exception;

HttpRestResult<String> httpDelete(String path, Map<String, String> headers, Map<String, String> paramValues, String encoding, long readTimeoutMs) throws Exception;

MetricsHttpAgent

public class MetricsHttpAgent implements HttpAgent {

? ? // 持有真正發(fā)起請(qǐng)求的 httpAgent

????private final HttpAgent httpAgent;

????public HttpRestResult<String> httpGet(String path, Map<String, String> headers, Map<String, String> paramValues, ????????String encode, long readTimeoutMs) throws Exception {

????????? ??Histogram.Timer timer = MetricsMonitor.getConfigRequestMonitor("GET", path, "NA");

????????????HttpRestResult<String> result;? ??????????

????????????try {? ??????????

? ? ? ? ? ? ? ? result = httpAgent.httpGet(path, headers, paramValues, encode, readTimeoutMs);

? ??????????} catch (IOException e) {

? ??????????????throw e;

? ??????????} finally {}

? ??????????return result;

? ? }

}

ServerHttpAgent?

public class ServerHttpAgent implements HttpAgent {

? ? // 核心類：nacosRestTemplate

? ? // 和springboot RestTemplate差不多 使用http協(xié)議對(duì)外交互

?????private static final NacosRestTemplate NACOS_RESTTEMPLATE = ConfigHttpClientManager.getInstance() .getNacosRestTemplate();

? ? // 針對(duì)?nacosRestTemplate 進(jìn)行安全配置

????private SecurityProxy securityProxy;

? ? // 調(diào)度器

? ??private ScheduledExecutorService executorService;

}

ServerHttpAgent

ServerListManager

public class ServerListManager implements Closeable {

? ??volatile List<String> serverUrls = new ArrayList<String>();

}

維護(hù)多個(gè)服務(wù)端地址

SecurityProxy

public class SecurityProxy {

? ??private String accessToken;

? ??private long tokenTtl;

? ??private long lastRefreshTime;

? ??public boolean login(List<String> servers) {

? ??????if ((System.currentTimeMillis() - lastRefreshTime) < TimeUnit.SECONDS .toMillis(tokenTtl - tokenRefreshWindow))? ? ? ? ? {

? ? ? ? ? ??return true;

? ? ? ? }

? ??????for (String server : servers) {

? ??????????if (login(server)) {

????????????????lastRefreshTime = System.currentTimeMillis();? ??????????

? ??????????????return true;

? ? ? ? ? ? }

? ? ? ? }

? ??????return false;

? ? }

}

SecurityProxy 會(huì)調(diào)用服務(wù)端進(jìn)行登錄，獲取到的accessToken和有效時(shí)間進(jìn)行儲(chǔ)存。如果失效了會(huì)重新發(fā)起登錄伦糯。

NacosRestTemplate

public class NacosRestTemplate extends AbstractNacosRestTemplate {

? ? // 具體的http client?

? ? // httpclient有兩種實(shí)現(xiàn) 1：使用Apache HttpClient? 2：使用JDK HttpUrlConnection

? ??private final HttpClientRequest requestClient;

? ? // http調(diào)用 攔截器 可以根據(jù)需求 定制自己的攔截器

? ??private final List<HttpClientRequestInterceptor> interceptors = new ArrayList<HttpClientRequestInterceptor>();

}

NacosRestTemplate UML

HttpClientRequest?

public interface HttpClientRequest extends Closeable {

? ? // 執(zhí)行請(qǐng)求并且返回結(jié)果

????HttpClientResponse execute(URI uri, String httpMethod, RequestHttpEntity requestHttpEntity) throws Exception;

}

http調(diào)用統(tǒng)一接口

DefaultHttpClientRequest

public class DefaultHttpClientRequest implements HttpClientRequest {

? ? //?implementation that uses apache http client to execute streaming requests.

? ? // 使用 appche http client 實(shí)現(xiàn)

????private final CloseableHttpClient client;

}

HttpClientRequest 默認(rèn)實(shí)現(xiàn)

JdkHttpClientRequest

public class JdkHttpClientRequest implements HttpClientRequest {

? ??private HttpClientConfig httpClientConfig;

? ??public HttpClientResponse execute(URI uri, String httpMethod, RequestHttpEntity requestHttpEntity){

? ? ? ? ………………

? ??????HttpURLConnection conn = (HttpURLConnection) uri.toURL().openConnection();

? ? ? ? ………………

? ? }

}

使用java? net包實(shí)現(xiàn)

InterceptingHttpClientRequest

public class InterceptingHttpClientRequest implements HttpClientRequest {

? ? // 持有httpClientRequest? 進(jìn)行包裝
? ? private final HttpClientRequest httpClientRequest;

? ? private final Iterator<HttpClientRequestInterceptor> interceptors;

? ??public HttpClientResponse execute(URI uri, String httpMethod, RequestHttpEntity requestHttpEntity){

? ??????while (interceptors.hasNext()) {

? ??????????HttpClientRequestInterceptor nextInterceptor = interceptors.next();

? ??????????if (nextInterceptor.isIntercept(uri, httpMethod, requestHttpEntity)) {

? ??????????????return nextInterceptor.intercept();

? ? ? ? ? ? }

? ??????????return httpClientRequest.execute(uri, httpMethod, requestHttpEntity);

? ? }

}

包裝了httpClientRequest，在執(zhí)行httpClientRequest.execute 增加了攔截邏輯嗽元。

ClientWorker

public class ClientWorker implements Closeable {

? ? …………

? ? // 緩存了 配置信息 key = dataId+GroupId

? ??private final AtomicReference<Map<String, CacheData>> cacheMap = new AtomicReference<Map<String, CacheData>>( new HashMap<String, CacheData>());

? ? …………

}

ClientWorker

checkConfigInfo 會(huì)根據(jù)cacheMap.size 進(jìn)行維護(hù)

ConfigService.getConfig 偽代碼

// 校驗(yàn)參數(shù) + 默認(rèn)配置

// 優(yōu)先使用本地配置??

String content = LocalConfigInfoProcessor.getFailover(agent.getName(), dataId, group, tenant);

if(content != null) return?content;

// 從服務(wù)端獲取配置信息 && 如果成功保存快照版本

try{

????String[] ct = worker.getServerConfig(dataId, group, tenant, timeoutMs);

} …………

// 如果從服務(wù)端獲取異常 直接獲取本地快照版本返回

content = LocalConfigInfoProcessor.getSnapshot(agent.getName(), dataId, group, tenant);

return?content;

涉及到的模式：

1舔株、工廠模式?NacosFactory 典型的簡(jiǎn)單工廠

2、模板模式 NacosRestTemplate

3还棱、裝飾器模式?MetricsHttpAgent

以上就是針對(duì)ConfigService客戶端的分析 载慈，下一章進(jìn)行服務(wù)端分析。