org.springframework.metrics.instrument.web.WebmvcMetricsHandlerInterceptor.java Source code

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Here is the source code for org.springframework.metrics.instrument.web.WebmvcMetricsHandlerInterceptor.java

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/**
 * Copyright 2017 Pivotal Software, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.springframework.metrics.instrument.web;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.env.Environment;
import org.springframework.metrics.instrument.MeterRegistry;
import org.springframework.metrics.instrument.Tag;
import org.springframework.metrics.instrument.Timer;
import org.springframework.metrics.instrument.annotation.Timed;
import org.springframework.web.context.request.RequestContextHolder;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Method;
import java.util.concurrent.TimeUnit;
import java.util.stream.IntStream;
import java.util.stream.Stream;

import static org.springframework.web.context.request.RequestAttributes.SCOPE_REQUEST;

/**
 * Intercepts incoming HTTP requests and records metrics about execution time and results.
 *
 * @author Jon Schneider
 */
public class WebmvcMetricsHandlerInterceptor extends HandlerInterceptorAdapter {

    private static final Log logger = LogFactory.getLog(WebmvcMetricsHandlerInterceptor.class);
    private static final String TIMING_REQUEST_ATTRIBUTE = "requestStartTime";

    @Autowired
    MeterRegistry registry;

    @Autowired
    Environment environment;

    @Autowired
    WebMetricsTagProvider provider;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        RequestContextHolder.getRequestAttributes().setAttribute(TIMING_REQUEST_ATTRIBUTE, System.nanoTime(),
                SCOPE_REQUEST);
        return super.preHandle(request, response, handler);
    }

    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler,
            Exception ex) throws Exception {
        RequestContextHolder.getRequestAttributes().setAttribute("exception", ex, SCOPE_REQUEST);

        Long startTime = (Long) RequestContextHolder.getRequestAttributes().getAttribute(TIMING_REQUEST_ATTRIBUTE,
                SCOPE_REQUEST);
        if (startTime != null)
            recordMetric(request, response, handler, startTime);

        super.afterCompletion(request, response, handler, ex);
    }

    private void recordMetric(HttpServletRequest request, HttpServletResponse response, Object handler,
            Long startTime) {
        long endTime = System.nanoTime();

        if (handler instanceof HandlerMethod) {

            Timed timed = ((HandlerMethod) handler).getMethod().getAnnotation(Timed.class);
            if (timed == null) {
                timed = ((HandlerMethod) handler).getBeanType().getAnnotation(Timed.class);
            }

            if (timed != null) {
                String name = environment.getProperty("spring.metrics.web.name", "http_server_requests");
                if (!timed.value().isEmpty()) {
                    name = timed.value();
                }

                Stream<Tag> tags = provider.httpRequestTags(request, response, handler, null);
                String[] extraTags = timed.extraTags();
                if (extraTags.length > 0) {
                    if (extraTags.length % 2 != 0) {
                        if (logger.isErrorEnabled()) {
                            Method method = ((HandlerMethod) handler).getMethod();
                            String target = method.getDeclaringClass().getName() + "." + method.getName();
                            logger.error("@Timed extraTags array on method " + target
                                    + " size must be even, it is a set of key=value pairs");
                        }
                    } else {
                        Stream<Tag> extraTagsStream = IntStream.range(0, extraTags.length / 2)
                                .mapToObj(i -> Tag.of(extraTags[i], extraTags[i + 1]));
                        tags = Stream.concat(tags, extraTagsStream);
                    }
                }

                Timer timer = registry.timer(name, tags);
                if (timer != null) {
                    timer.record(endTime - startTime, TimeUnit.NANOSECONDS);
                }
            }
        }
    }
}