fabiosoaza/spring-rest-base

package com.restbase.application.rest.controller.interceptor;

import java.io.IOException;
import java.util.UUID;

import javax.servlet.FilterChain;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.MDC;
import org.springframework.util.StopWatch;
import org.springframework.util.StringUtils;
import org.springframework.web.filter.OncePerRequestFilter;

import com.restbase.application.constant.Constants;

import lombok.extern.slf4j.Slf4j;

@Slf4j
public class MDCInterceptor  extends OncePerRequestFilter {
    
    @Override
    protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
            throws ServletException, IOException {

        String tracerBullet = request.getHeader(Constants.TRACER_BULLET_HEADER);

        if (!StringUtils.isEmpty(tracerBullet)) {
            setTracerBullet(tracerBullet);
            log.debug("Header {} value put into MDC is {}", Constants.TRACER_BULLET, tracerBullet);
        } else {
            tracerBullet = UUID.randomUUID().toString();
            setTracerBullet(tracerBullet);
            log.debug("Header {} is empty. Generated local {} value is {}", Constants.TRACER_BULLET, Constants.TRACER_BULLET, tracerBullet);
        }

        StopWatch watch = new StopWatch();
        watch.start();

        filterChain.doFilter(request, response);

        watch.stop();
        log.info("Request processed in {} ms", watch.getTotalTimeMillis());

        MDC.remove(Constants.TRACER_BULLET);

    }

    protected void setTracerBullet(String tracerBullet) {
        MDC.put(Constants.TRACER_BULLET, tracerBullet);
    }

}