SpringBoot 之 MDC 实现全链路调用日志跟踪

日志拦截器

import com.evcas.charge.pile.platform.common.annotation.LogNoTrace;
import com.evcas.charge.pile.platform.common.utils.StringUtils;
import org.slf4j.MDC;
import org.springframework.lang.Nullable;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.UUID;

public class LogInterceptor implements HandlerInterceptor {

    private static final String TRACE_ID = "traceId";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        Method method = ((HandlerMethod) handler).getMethod();
        if (method.isAnnotationPresent(LogNoTrace.class)) {
            return true;
        }
        String tid = UUID.randomUUID().toString().replace("-", "").substring(0, 10);
        // 如果有上层调用就用上层的ID
        if (!StringUtils.isEmpty(request.getHeader(TRACE_ID))) {
            tid = request.getHeader(TRACE_ID);
        }
        MDC.put(TRACE_ID, tid);
        return true;
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
                                @Nullable Exception ex) {
        MDC.remove(TRACE_ID);
    }

}

import java.lang.annotation.*;

/**
 * 不需要日志跟踪
 */
@Inherited
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface LogNoTrace {

}

import com.gotion.opencenter.interceptor.LogInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;

@Configuration
public class WebConfigurerAdapter implements WebMvcConfigurer {
    @Bean
    public LogInterceptor logInterceptor() {
        return new LogInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logInterceptor());
    }
}

修改日志格式

<property name="pattern">%d{HH:mm:ss.SSS} %X{traceId} %-5level %class{-1}.%M()/%L - %msg%xEx%n</property>

重点是 %X{traceId} traceId 和 MDC 中的键名称一致。

trackId 丢失解决

异步子线程会丢失了trackId：
思路： 将父线程的trackId传递下去给子线程即可。

1、自定义线程池，交给 Spring 管理

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import java.util.concurrent.Executor;

@Configuration
@EnableAsync
public class MyThreadPoolConfig {
    @Bean("MyExecutor")
    public Executor asyncExecutor() {
        MyThreadPoolTaskExecutor executor = new MyThreadPoolTaskExecutor();
        //核心线程数5：线程池创建时候初始化的线程数
        executor.setCorePoolSize(5);
        //最大线程数5：线程池最大的线程数，只有在缓冲队列满了之后才会申请超过核心线程数的线程
        executor.setMaxPoolSize(5);
        //缓冲队列500：用来缓冲执行任务的队列
        executor.setQueueCapacity(500);
        //允许线程的空闲时间60秒：当超过了核心线程出之外的线程在空闲时间到达之后会被销毁
        executor.setKeepAliveSeconds(60);
        //线程池名的前缀：设置好了之后可以方便我们定位处理任务所在的线程池
        executor.setThreadNamePrefix("myExecutor");
        executor.initialize();
        return executor;
    }
}

import org.slf4j.MDC;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Callable;
import java.util.concurrent.Future;

public class MyThreadPoolTaskExecutor extends ThreadPoolTaskExecutor {

    public MyThreadPoolTaskExecutor() {
        super();
    }

    @Override
    public void execute(Runnable task) {
        super.execute(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
    }


    @Override
    public <T> Future<T> submit(Callable<T> task) {
        return super.submit(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
    }

    @Override
    public Future<?> submit(Runnable task) {
        return super.submit(ThreadMdcUtil.wrap(task, MDC.getCopyOfContextMap()));
    }
}

import org.slf4j.MDC;

import java.util.Map;
import java.util.UUID;
import java.util.concurrent.Callable;

public class ThreadMdcUtil {

    private static final String TRACE_ID = "traceId";

    // 获取唯一性标识
    public static String generateTraceId() {
        return UUID.randomUUID().toString();
    }

    public static void setTraceIdIfAbsent() {
        if (MDC.get(TRACE_ID) == null) {
            MDC.put(TRACE_ID, generateTraceId());
        }
    }

    /**
     * 用于父线程向线程池中提交任务时，将自身MDC中的数据复制给子线程
     *
     * @param callable
     * @param context
     * @param <T>
     * @return
     */
    public static <T> Callable<T> wrap(final Callable<T> callable, final Map<String, String> context) {
        return () -> {
            if (context == null) {
                MDC.clear();
            } else {
                MDC.setContextMap(context);
            }
            setTraceIdIfAbsent();
            try {
                return callable.call();
            } finally {
                MDC.clear();
            }
        };
    }

    /**
     * 用于父线程向线程池中提交任务时，将自身MDC中的数据复制给子线程
     *
     * @param runnable
     * @param context
     * @return
     */
    public static Runnable wrap(final Runnable runnable, final Map<String, String> context) {
        return () -> {
            if (context == null) {
                MDC.clear();
            } else {
                MDC.setContextMap(context);
            }
            setTraceIdIfAbsent();
            try {
                runnable.run();
            } finally {
                MDC.clear();
            }
        };
    }
}

SpringBoot + MDC 实现全链路调用日志跟踪