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nacos client中ServerHttpAgent的原理和使用方法

发表于:2024-11-12 作者:千家信息网编辑
千家信息网最后更新 2024年11月12日,这篇文章主要介绍"nacos client中ServerHttpAgent的原理和使用方法",在日常操作中,相信很多人在nacos client中ServerHttpAgent的原理和使用方法问题上存
千家信息网最后更新 2024年11月12日nacos client中ServerHttpAgent的原理和使用方法

这篇文章主要介绍"nacos client中ServerHttpAgent的原理和使用方法",在日常操作中,相信很多人在nacos client中ServerHttpAgent的原理和使用方法问题上存在疑惑,小编查阅了各式资料,整理出简单好用的操作方法,希望对大家解答"nacos client中ServerHttpAgent的原理和使用方法"的疑惑有所帮助!接下来,请跟着小编一起来学习吧!

本文主要研究一下nacos client的ServerHttpAgent

HttpAgent

nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/http/HttpAgent.java

public interface HttpAgent {    /**     * start to get nacos ip list     * @return Nothing.     * @throws NacosException on get ip list error.     */    void start() throws NacosException;    /**     * invoke http get method     * @param path http path     * @param headers http headers     * @param paramValues http paramValues http     * @param encoding http encode     * @param readTimeoutMs http timeout     * @return HttpResult http response     * @throws IOException If an input or output exception occurred     */    HttpResult httpGet(String path, List headers, List paramValues, String encoding, long readTimeoutMs) throws IOException;    /**     * invoke http post method     * @param path http path     * @param headers http headers     * @param paramValues http paramValues http     * @param encoding http encode     * @param readTimeoutMs http timeout     * @return HttpResult http response     * @throws IOException If an input or output exception occurred     */    HttpResult httpPost(String path, List headers, List paramValues, String encoding, long readTimeoutMs) throws IOException;    /**     * invoke http delete method     * @param path http path     * @param headers http headers     * @param paramValues http paramValues http     * @param encoding http encode     * @param readTimeoutMs http timeout     * @return HttpResult http response     * @throws IOException If an input or output exception occurred     */    HttpResult httpDelete(String path, List headers, List paramValues, String encoding, long readTimeoutMs) throws IOException;    /**     * get name     * @return String     */    String getName();    /**     * get namespace     * @return String     */    String getNamespace();    /**     * get tenant     * @return String     */    String getTenant();    /**     * get encode     * @return String     */    String getEncode();}
  • HttpAgent定义了start、httpGet、httpPost、httpDelete、getName、getNamespace、getTenant、getEncode方法

ServerHttpAgent

nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/http/ServerHttpAgent.java

public class ServerHttpAgent implements HttpAgent {    private static final Logger LOGGER = LogUtils.logger(ServerHttpAgent.class);    /**     * @param path          相对于web应用根,以/开头     * @param headers     * @param paramValues     * @param encoding     * @param readTimeoutMs     * @return     * @throws IOException     */    @Override    public HttpResult httpGet(String path, List headers, List paramValues, String encoding,                              long readTimeoutMs) throws IOException {        final long endTime = System.currentTimeMillis() + readTimeoutMs;        final boolean isSSL = false;        String currentServerAddr = serverListMgr.getCurrentServerAddr();        int maxRetry = this.maxRetry;        do {            try {                List newHeaders = getSpasHeaders(paramValues);                if (headers != null) {                    newHeaders.addAll(headers);                }                HttpResult result = HttpSimpleClient.httpGet(                    getUrl(currentServerAddr, path), newHeaders, paramValues, encoding,                    readTimeoutMs, isSSL);                if (result.code == HttpURLConnection.HTTP_INTERNAL_ERROR                    || result.code == HttpURLConnection.HTTP_BAD_GATEWAY                    || result.code == HttpURLConnection.HTTP_UNAVAILABLE) {                    LOGGER.error("[NACOS ConnectException] currentServerAddr: {}, httpCode: {}",                        serverListMgr.getCurrentServerAddr(), result.code);                } else {                    // Update the currently available server addr                    serverListMgr.updateCurrentServerAddr(currentServerAddr);                    return result;                }            } catch (ConnectException ce) {                LOGGER.error("[NACOS ConnectException httpGet] currentServerAddr:{}, err : {}", serverListMgr.getCurrentServerAddr(), ce.getMessage());            } catch (SocketTimeoutException stoe) {                LOGGER.error("[NACOS SocketTimeoutException httpGet] currentServerAddr:{}, err : {}", serverListMgr.getCurrentServerAddr(), stoe.getMessage());            } catch (IOException ioe) {                LOGGER.error("[NACOS IOException httpGet] currentServerAddr: " + serverListMgr.getCurrentServerAddr(), ioe);                throw ioe;            }            if (serverListMgr.getIterator().hasNext()) {                currentServerAddr = serverListMgr.getIterator().next();            } else {                maxRetry --;                if (maxRetry < 0) {                    throw new ConnectException("[NACOS HTTP-GET] The maximum number of tolerable server reconnection errors has been reached");                }                serverListMgr.refreshCurrentServerAddr();            }        } while (System.currentTimeMillis() <= endTime);        LOGGER.error("no available server");        throw new ConnectException("no available server");    }    @Override    public HttpResult httpPost(String path, List headers, List paramValues, String encoding,                               long readTimeoutMs) throws IOException {        final long endTime = System.currentTimeMillis() + readTimeoutMs;        boolean isSSL = false;        String currentServerAddr = serverListMgr.getCurrentServerAddr();        int maxRetry = this.maxRetry;        do {            try {                List newHeaders = getSpasHeaders(paramValues);                if (headers != null) {                    newHeaders.addAll(headers);                }                HttpResult result = HttpSimpleClient.httpPost(                    getUrl(currentServerAddr, path), newHeaders, paramValues, encoding,                    readTimeoutMs, isSSL);                if (result.code == HttpURLConnection.HTTP_INTERNAL_ERROR                    || result.code == HttpURLConnection.HTTP_BAD_GATEWAY                    || result.code == HttpURLConnection.HTTP_UNAVAILABLE) {                    LOGGER.error("[NACOS ConnectException] currentServerAddr: {}, httpCode: {}",                        currentServerAddr, result.code);                } else {                    // Update the currently available server addr                    serverListMgr.updateCurrentServerAddr(currentServerAddr);                    return result;                }            } catch (ConnectException ce) {                LOGGER.error("[NACOS ConnectException httpPost] currentServerAddr: {}, err : {}", currentServerAddr, ce.getMessage());            } catch (SocketTimeoutException stoe) {                LOGGER.error("[NACOS SocketTimeoutException httpPost] currentServerAddr: {}, err : {}", currentServerAddr, stoe.getMessage());            } catch (IOException ioe) {                LOGGER.error("[NACOS IOException httpPost] currentServerAddr: " + currentServerAddr, ioe);                throw ioe;            }            if (serverListMgr.getIterator().hasNext()) {                currentServerAddr = serverListMgr.getIterator().next();            } else {                maxRetry --;                if (maxRetry < 0) {                    throw new ConnectException("[NACOS HTTP-POST] The maximum number of tolerable server reconnection errors has been reached");                }                serverListMgr.refreshCurrentServerAddr();            }        } while (System.currentTimeMillis() <= endTime);        LOGGER.error("no available server, currentServerAddr : {}", currentServerAddr);        throw new ConnectException("no available server, currentServerAddr : " + currentServerAddr);    }    //......}
  • ServerHttpAgent实现了HttpAgent接口,其httpGet、httpPost、httpDelete方法的结构大体相同,都是以do while做循环,循环条件为距离开始执行时间不超过readTimeoutMs

  • 循环开始之前会通过serverListMgr.getCurrentServerAddr()方法获取currentServerAddr,循环体内则通过HttpSimpleClient的相应方法执行请求,如果返回的HTTP Code为HTTP_INTERNAL_ERROR、HTTP_BAD_GATEWAY、HTTP_UNAVAILABLE则打印error日志,否则执行serverListMgr.updateCurrentServerAddr(currentServerAddr),然后返回

  • 如果出现异常或者没有提前返回,则判断serverListMgr.getIterator().hasNext(),如果为true则使用serverListMgr.getIterator().next()更新currentServerAddr,为false则递减maxRetry,然后执行serverListMgr.refreshCurrentServerAddr()

小结

ServerHttpAgent实现了HttpAgent接口,其httpGet、httpPost、httpDelete方法的结构大体相同,都是以do while做循环,循环条件为距离开始执行时间不超过readTimeoutMs

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