springCloud微服务系列——链路跟踪第二篇——mvc链路跟踪器

柔光的暖阳◎ 2022-05-18 10:26 250阅读 0赞

**目录**

一、简介

二、思路

三、spring mvc

四、示例代码

--------------------

# 一、简介 #

这篇文章总结一下mvc链路跟踪器的实现，这篇文章的内容相对比较简单。

# 二、思路 #

上一篇文章其实已经顺带把mvc链路跟踪器的思路说了

1、初始化上下文，新建ThreadLoacal

2、从http中获取traceId信息

如果有说明是被别的服务调用，将http中的traceId和rpceId保存到上下文

如果没有说明请求来自于客户端，新建链路跟踪信息，保存到上下文

3、处理结束后将上下文销毁

[《springCloud微服务系列——链路跟踪第一篇——设计思路以及通用链路跟踪器》][springCloud]

# 三、spring mvc #

如果controller层为spring mvc，那么可以使用拦截器拦截请求进行链路跟踪，非常简单。

# 四、示例代码 #

public class MvcTracker implements Tracker<MvcHolder> {
 
 	private static final FastDateFormat ISO_DATETIME_TIME_ZONE_FORMAT_WITH_MILLIS = FastDateFormat.getInstance("yyyy-MM-dd'T'HH:mm:ss.SSSZZ");
 	
 	protected static final String BEGIN_TIME_KEY = "beginTime";
 	
 	protected static final String RPC_TRACE_INFO_VO_KEY = "rpcTraceInfoVO";
 	
 	protected TraceClient traceClient;
 	
 	public MvcTracker(TraceClient traceClient) {
 		this.traceClient = traceClient;
 	}
 	
 	@Override
 	public void preHandle(MvcHolder holder) {
 		initTraceData(holder.getRequest(), holder.getHandler(), holder.getProfile());
 	}
 	
 	@Override
 	public void postHandle(MvcHolder holder) {
 		finishTraceData(holder.getRequest(), holder.getResponse(), holder.getException());
 	}
 	
 	private void initTraceData (HttpServletRequest request, Object handler, String profile) {
 		// 开始时间
 		request.setAttribute(BEGIN_TIME_KEY, System.currentTimeMillis());
 		// 为当前线程设置上下文
 		TraceContext.init();
 		// 链路跟踪信息基础对象
 		TraceInfo traceInfo = new TraceInfo();
 		
 		String traceIdFromHeader = request.getHeader(TraceInfo.TRACE_ID_KEY);
 		
 		Optional.ofNullable(traceIdFromHeader)
 			.ifPresent(traceId->{
 			traceInfo.setTraceId(traceId);
 		});
 		
 		Optional.ofNullable(
 				request.getHeader(TraceInfo.RPC_ID_KEY)
 		).ifPresent(rpcId->{
 			traceInfo.setRpcId(rpcId);
 		});
 		
 		if(traceIdFromHeader != null) {
 			traceInfo.setRootRpcId(traceInfo.getRpcId());
 		} else {
 			traceInfo.setRootRpcId(TraceInfo.RE_ORIGINAL_ROOT_RPC_ID);
 		}
 		
 		// 封装链路跟踪数据
 		if(handler != null && handler instanceof HandlerMethod && traceIdFromHeader == null) {
 			HandlerMethod handlerMethod = (HandlerMethod) handler;
 			 
 			Gson gson =new Gson();
 			 
 			String serviceName = null;
 			try {
 				serviceName = TargetUtils.getTarget(handlerMethod.getBean()).getClass().getSimpleName();
 			} catch (Exception e) {
 				 serviceName = handlerMethod.getBean().getClass().getSimpleName();
 			}
 			 if(serviceName == null) {
 				 serviceName = handlerMethod.getBean().getClass().getSimpleName();
 			 }
 			 
 			 RpcTraceInfoVO rpcTraceInfoVO = new RpcTraceInfoVO();
 			 rpcTraceInfoVO.setProfile(profile);
 			 rpcTraceInfoVO.setRequestDateTime(ISO_DATETIME_TIME_ZONE_FORMAT_WITH_MILLIS.format(Calendar.getInstance().getTime()));
 			 rpcTraceInfoVO.setTraceId(traceInfo.getTraceId());
 			 rpcTraceInfoVO.setRpcId(traceInfo.getRpcId());
 			 rpcTraceInfoVO.setRpcType(RpcTypeEnum.HTTP.name());
 			 rpcTraceInfoVO.setServiceCategory("spring mvc");
 			 rpcTraceInfoVO.setServiceName(handlerMethod.getBean().getClass().getName().split("\\$\\$")[0]);
 			 rpcTraceInfoVO.setMethodName(handlerMethod.getMethod().getName());
 			 rpcTraceInfoVO.setRequestParam(gson.toJson(request.getParameterMap()));
 			 rpcTraceInfoVO.setServiceHost(HostUtil.getIP()+":"+request.getLocalPort()+request.getServletPath());
 			 rpcTraceInfoVO.setClientHost(HostUtil.getIP(request));
 			 
 			 request.setAttribute(RPC_TRACE_INFO_VO_KEY, rpcTraceInfoVO);
 		}
 		
 		// 增加层级
 		//traceInfo.addHierarchy();
 		
 		// 链路跟踪信息保存到当前线程上下文中
 		TraceContext.putTraceInfo(traceInfo);
 		MDC.put(TraceInfo.TRACE_ID_KEY, traceInfo.getTraceId());
 		MDC.put(TraceInfo.RPC_ID_KEY, traceInfo.getRpcId());
 	}
 	
 	private void finishTraceData(HttpServletRequest request, HttpServletResponse response, Exception ex) {
 		try {
 			String traceIdFromHeader = request.getHeader(TraceInfo.TRACE_ID_KEY);
 			if(traceIdFromHeader != null)
 				return;
 			RpcTraceInfoVO rpcTraceInfoVO = (RpcTraceInfoVO) request.getAttribute(RPC_TRACE_INFO_VO_KEY);
 			if(rpcTraceInfoVO != null) {
 					long beginTime = (Long) request.getAttribute(BEGIN_TIME_KEY);
 					rpcTraceInfoVO.setRunTime(System.currentTimeMillis() - beginTime);
 					if(ex == null) {
 						rpcTraceInfoVO.setResult(RpcTraceInfoVO.RESULT_SUCCESS);
 					} else {
 						rpcTraceInfoVO.setResult(RpcTraceInfoVO.RESULT_FAILURE);
 						rpcTraceInfoVO.setResponseInfo(ex.getMessage());
 					}
 					Gson gson = new Gson();
 					log.debug(gson.toJson(rpcTraceInfoVO));
 					traceClient.sendTraceInfo(rpcTraceInfoVO);
 			}
 		} catch (Exception e) {
 			log.error(e.getMessage(), e);
 		} finally {
 			request.removeAttribute(RPC_TRACE_INFO_VO_KEY);
 			TraceContext.removeTraceInfo();
 			MDC.remove(TraceInfo.TRACE_ID_KEY);
 			MDC.remove(TraceInfo.RPC_ID_KEY);
 		}
 	}
 	
 }

public class SpringMvcTracker extends MvcTracker implements Tracker<MvcHolder> {
 
 	public SpringMvcTracker (TraceClient traceClient) {
 		super(traceClient);
 		this.traceClient = traceClient;
 	}
 	
 }

@Slf4j
 public class TraceInteceptor extends HandlerInterceptorAdapter {
 
 	private String profile;
 	
 	private Tracker<MvcHolder> tracker;
 	
 	public TraceInteceptor (String profile, Tracker<MvcHolder> tracker) {
 		super();
 		this.profile = profile;
 		this.tracker = tracker;
 	}
 	
 	/**
 	 * 
 	 * http请求处理前操作
 	 * 
 	 */
 	@Override
 public boolean preHandle(HttpServletRequest request, HttpServletResponse response,
 Object handler) throws Exception {
 		log.info("http preHandle");
 		if(isTraceHandler(handler)) {
 			MvcHolder mvcHolder = new MvcHolder();
 			mvcHolder.setProfile(profile);
 			mvcHolder.setRequest(request);
 			mvcHolder.setResponse(response);
 			mvcHolder.setHandler(handler);
 			tracker.preHandle(mvcHolder);
 		}
 		
 		return super.preHandle(request, response, handler);
 	}
 	
 	/**
 	 * 
 	 * http请求处理完操作
 	 * 
 	 */
 	@Override
 	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
 			@Nullable Exception ex) throws Exception {
 		log.info("http afterCompletion");
 		MvcHolder mvcHolder = new MvcHolder();
 		mvcHolder.setRequest(request);
 		mvcHolder.setResponse(response);
 		mvcHolder.setHandler(handler);
 		mvcHolder.setException(ex);
 		tracker.postHandle(mvcHolder);
 	}
 	
 	/**
 	 * 
 	 * Title: isTraceHandler 
 	 * Description: 是否被@Trace注释 
 	 * @param handler
 	 * @return
 	 */
 	public boolean isTraceHandler(Object handler) {
 Object annoation = getAnnotation(handler);
 if (annoation == null)
 return false;
 Trace trace = (Trace) annoation;
 if(!trace.value().getName().equals(SpringMvcTracker.class.getName()))
 	return false;
 return true;
 }
 	
 	/**
 	 * 
 	 * Title: getAnnotation 
 	 * Description: 获得@Trace注释 
 	 * @param handler
 	 * @return
 	 */
 	private Object getAnnotation(Object handler) {
 		if(handler == null)
 			return null;
 		
 	if (!(handler instanceof HandlerMethod))
 return null;
 	
 	Object annoation = null;
 	
 HandlerMethod handlerMethod = (HandlerMethod) handler;
 annoation = handlerMethod.getMethodAnnotation(Trace.class);
 return annoation;
 }
 	
 }

[https://github.com/wulinfeng2/luminary-component][https_github.com_wulinfeng2_luminary-component]

[springCloud]: https://blog.csdn.net/guduyishuai/article/details/81357249
[https_github.com_wulinfeng2_luminary-component]: https://github.com/wulinfeng2/luminary-component