记一次生产事故排查-编程知识

背景：刚接手一个新工程，是一个给国内top级医院开发的老项目，因为历史原因，代码质量略低，测试难度略高。

上线很久的功能，最近一直频繁的爆发各种问题，经排查发现都是因为在业务过程中im聊天账号绑定异常所致。

修复方案一：

因为im工程比较老，日志打印不完善，因此从日志看初步分析业务dubbo接口未调用到im服务因此导致了绑定失败，此时我开始在工程里设置dubbo接口该方法的重试机制，retries设置为2，timeout设置为3000，由于本身既有的一次rpc调用，因此实际在调用失败的情况下业务会对im接口进行3次rpc的调用。

鉴于项目的各种难度和稳定性要求，另在业务代码侧再次进行了三次递归重试（客户端超时30s，正常情况不会因为重试而超时，慢是肯定的）。

同时因为服务此时并没有打印traceId进行链路跟踪机制的拓展，因此另开发traceId写入MDC并通过log4j2打印到cosole并通过钉钉表达式进行采集汇总输出，针对dubbo接口也通过扩展spi进行了traceId的透传。

服务消费者端代码如下：

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;
import org.springframework.core.Ordered;
import org.springframework.core.annotation.Order;
import org.springframework.web.filter.OncePerRequestFilter;
import org.springframework.web.util.ContentCachingRequestWrapper;import javax.servlet.FilterChain;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;/*** MDC属性设置  日志用* 方法屏蔽actuator接口*/
@Order(Ordered.HIGHEST_PRECEDENCE)
@WebFilter(urlPatterns = {"/*"})
public class MDCFilter extends OncePerRequestFilter {private  Logger LOGGER = LoggerFactory.getLogger(MDCFilter.class);@Overrideprotected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain chain) {if(request.getRequestURI().contains("/actuator/health")){return;}try {String traceId = request.getHeader("traceId");if(StringUtils.isNotBlank(traceId)) {TraceIdUtil.create(traceId);} else {TraceIdUtil.create();}TraceContext.addAttachment("traceId",MDC.get("traceId"));chain.doFilter(new ContentCachingRequestWrapper(request), response);} catch (Exception exception) {LOGGER.error("Web端traceId处理异常", exception);} finally {TraceContext.clear();TraceIdUtil.clear();}}}

import java.util.UUID;
import org.slf4j.MDC;public class TraceIdUtil {public static final String TRACE_ID = "traceId";public TraceIdUtil() {}public static void create() {create(UUID.randomUUID().toString().replace("-", ""));}public static void create(String traceId) {MDC.put("traceId", traceId);}public static String get() {return MDC.get("traceId");}public static void clear() {MDC.clear();}
}

import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.rpc.*;@Activate(group = {"consumer"})
public class DubboTraceFilter implements Filter {@Overridepublic Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {RpcContext rpcContext = RpcContext.getContext();if (rpcContext.isConsumerSide()) {rpcContext.setAttachment("traceId", TraceContext.getTraceId());}return invoker.invoke(invocation);}
}

public class TraceContext {private static ThreadLocal<Map<String,Object>> threadLocal = new ThreadLocal<Map<String, Object>>(){@Overrideprotected Map<String, Object> initialValue() {return new LinkedHashMap<String, Object>();}};public static void addAttachment(String key, Object value){threadLocal.get().put(key,value);}public static void addAttachments(Map<String, Object> map){threadLocal.get().putAll(map);}public static Map<String, Object> getAttachments(){return threadLocal.get();}public static  void clear(){threadLocal.remove();}public static String getTraceId(){return String.valueOf(threadLocal.get().get("traceId"));}}

启动类添加注解：@ServletComponentScan

resource目录新建文件com.alibaba.dubbo.rpc.Filter

文件内容

dubboTraceFilter=com.xxx.filter.DubboTraceFilter（文件路径）

文件结构如下

服务提供者端代码如下：

import com.alibaba.dubbo.common.extension.Activate;
import com.alibaba.dubbo.rpc.*;
import org.apache.commons.lang.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.slf4j.MDC;@Activate(group = {"provider","consumer"})
public class TraceIdFilter implements Filter {private static final Logger LOGGER = LoggerFactory.getLogger(TraceIdFilter.class);@Overridepublic Result invoke(Invoker<?> invoker, Invocation invocation) throws RpcException {try{String traceId = RpcContext.getContext().getAttachment("traceId");if ( !StringUtils.isEmpty(traceId) ) {// *) 从RpcContext里获取traceId并保存MDC.put("traceId", traceId);} else {// *) 交互前重新设置traceId, 避免信息丢失TraceIdUtil.create();RpcContext.getContext().setAttachment("traceId", MDC.get("traceId"));}// *) 实际的rpc调用return invoker.invoke(invocation);}catch (Exception e){LOGGER.error("rpcContext get traceId exception:",e);return null;}finally {TraceIdUtil.clear();}}
}

提供者端SPI扩展相同