日志链路追踪

SpringBoot日志链路追踪

使用步骤

导入依赖：

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-logging</artifactId>
</dependency>

配置resources/logback-spring.xml:

<?xml version="1.0" encoding="UTF-8"?>
<configuration debug="false">
    <!--日志存储路径-->
    <property name="log" value="./logs" />
    <!-- 控制台输出 -->
    <appender name="console" class="ch.qos.logback.core.ConsoleAppender">
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <!--输出格式化-->
            <pattern>[%X{TRACE_ID}]  %d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
        </encoder>
    </appender>
    <!-- 按天生成日志文件 -->
    <appender name="file" class="ch.qos.logback.core.rolling.RollingFileAppender">
        <rollingPolicy class="ch.qos.logback.core.rolling.TimeBasedRollingPolicy">
            <!--日志文件名-->
            <FileNamePattern>${log}/%d{yyyy-MM-dd}.log</FileNamePattern>
            <!--保留天数-->
            <MaxHistory>30</MaxHistory>
        </rollingPolicy>
        <encoder class="ch.qos.logback.classic.encoder.PatternLayoutEncoder">
            <pattern>[%X{TRACE_ID}]  %d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] %-5level %logger{50} - %msg%n</pattern>
        </encoder>
        <!--日志文件最大的大小-->
        <triggeringPolicy class="ch.qos.logback.core.rolling.SizeBasedTriggeringPolicy">
            <MaxFileSize>10MB</MaxFileSize>
        </triggeringPolicy>
    </appender>

    <!-- 日志输出级别 -->
    <root level="INFO">
        <appender-ref ref="console" />
        <appender-ref ref="file" />
    </root>
</configuration>

在application.yml中指定日志配置的路径：

logging:
  config: classpath:logback-spring.xml

编写日志拦截器：

public class LogInterceptor implements HandlerInterceptor {

    private static final String TRACE_ID = "TRACE_ID";

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        String tid = UUID.randomUUID().toString().replace("-", "");
        // 可以考虑让客户端传入链路ID，但需保证一定的复杂度唯一性；如果没使用默认UUID自动生成
        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);
    }
}

配置拦截器：

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

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(logInterceptor()).addPathPatterns("/**");
        //可以具体制定哪些需要拦截，哪些不拦截，其实也可以使用自定义注解更灵活完成
        //  .excludePathPatterns("/testxx.html");
    }
}

测试：

@ResponseBody
@GetMapping(value = "/pay/{orderSn}")
public String alipay(@PathVariable("orderSn") String orderSn) {
    log.info("我开始了！");
    String result = orderService.alipay(orderSn);
    log.info("我结束了！{}",result);
    return result;
}

@Override
public String alipay(String orderSn) {
    try {
        log.info("开始查询");
        Thread.sleep(1000);
        int i = 10 / 0;
    } catch (Exception e) {
        log.error("有个错误：{}", e.getMessage());
    }
    log.info("查询结束");
    return "haha";
}

效果：

异步问题

如果是异步，会找不到id

解决办法：

将父线程的trace ID传递给子线程

包装类：

对Task进行装饰，将父线程的traceID放到子线程中

public final 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()));
    }
}

配置线程池，传递刚刚写的装饰器：

@Configuration
@EnableAsync
public class ThreadPoolConfig {
    @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("asyncJCccc");
        executor.initialize();
        return executor;
    }
}

工具类：

public final class ThreadMdcUtil {
    private static final String TRACE_ID = "TRACE_ID";

    // 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
     */
    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
     */
    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();
            }
        };
    }
}

分布式链路追踪

todo