聊聊nacos client的ServerHttpAgent
阿新 • • 發佈:2019-12-31
序
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 read TimeoutMs http timeout
* @return HttpResult http response
* @throws IOException If an input or output exception occurred
*/
HttpResult httpGet(String path,List<String> headers,List<String> 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 read TimeoutMs http timeout
* @return HttpResult http response
* @throws IOException If an input or output exception occurred
*/
HttpResult httpPost(String path,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 read TimeoutMs http timeout
* @return HttpResult http response
* @throws IOException If an input or output exception occurred
*/
HttpResult httpDelete(String path,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();
}
複製程式碼
- HttpAgent定義了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 相對於web應用根,以/開頭
* @param headers
* @param paramValues
* @param encoding
* @param readTimeoutMs
* @return
* @throws IOException
*/
@Override
public HttpResult httpGet(String path,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<String> 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 : {}",ce.getMessage());
} catch (SocketTimeoutException stoe) {
LOGGER.error("[NACOS SocketTimeoutException httpGet] currentServerAddr:{}, err : {}",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,long readTimeoutMs) throws IOException {
final long endTime = System.currentTimeMillis() + readTimeoutMs;
boolean isSSL = false;
String currentServerAddr = serverListMgr.getCurrentServerAddr();
int maxRetry = this.maxRetry;
do {
try {
List<String> newHeaders = getSpasHeaders(paramValues);
if (headers != null) {
newHeaders.addAll(headers);
}
HttpResult result = HttpSimpleClient.httpPost(
getUrl(currentServerAddr,currentServerAddr,result.code);
} else {
// Update the currently available server addr
serverListMgr.updateCurrentServerAddr(currentServerAddr);
return result;
}
} catch (ConnectException ce) {
LOGGER.error("[NACOS ConnectException httpPost] currentServerAddr: {},ce.getMessage());
} catch (SocketTimeoutException stoe) {
LOGGER.error("[NACOS SocketTimeoutException httpPost] currentServerAddr: {}, err : {}",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);
}
//......
}
複製程式碼
- ServerHttpAgent實現了HttpAgent介面,其httpGet、httpPost、httpDelete方法的結構大體相同,都是以do while做迴圈,迴圈條件為距離開始執行時間不超過readTimeoutMs
- 迴圈開始之前會通過serverListMgr.getCurrentServerAddr()方法獲取currentServerAddr,迴圈體內則通過HttpSimpleClient的相應方法執行請求,如果返回的HTTP Code為HTTP_INTERNAL_ERROR、HTTP_BAD_GATEWAY、HTTP_UNAVAILABLE則列印error日誌,否則執行serverListMgr.updateCurrentServerAddr(currentServerAddr),然後返回
- 如果出現異常或者沒有提前返回,則判斷serverListMgr.getIterator().hasNext(),如果為true則使用serverListMgr.getIterator().next()更新currentServerAddr,為false則遞減maxRetry,然後執行serverListMgr.refreshCurrentServerAddr()
小結
ServerHttpAgent實現了HttpAgent介面,其httpGet、httpPost、httpDelete方法的結構大體相同,都是以do while做迴圈,迴圈條件為距離開始執行時間不超過readTimeoutMs