org.springframework.cloud.gateway.filter.GatewayMetricsFilter.java Source code

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Here is the source code for org.springframework.cloud.gateway.filter.GatewayMetricsFilter.java

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/*
 * Copyright 2013-2019 the original author or authors.
 *
 * 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
 *
 *      https://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.cloud.gateway.filter;

import io.micrometer.core.instrument.MeterRegistry;
import io.micrometer.core.instrument.Tags;
import io.micrometer.core.instrument.Timer;
import io.micrometer.core.instrument.Timer.Sample;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import reactor.core.publisher.Mono;

import org.springframework.cloud.gateway.route.Route;
import org.springframework.core.Ordered;
import org.springframework.http.HttpStatus;
import org.springframework.http.server.reactive.AbstractServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.web.server.ServerWebExchange;

import static org.springframework.cloud.gateway.support.ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR;

public class GatewayMetricsFilter implements GlobalFilter, Ordered {

    private final Log log = LogFactory.getLog(getClass());

    private final MeterRegistry meterRegistry;

    public GatewayMetricsFilter(MeterRegistry meterRegistry) {
        this.meterRegistry = meterRegistry;
    }

    @Override
    public int getOrder() {
        // start the timer as soon as possible and report the metric event before we write
        // response to client
        return Ordered.HIGHEST_PRECEDENCE + 10000;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        Sample sample = Timer.start(meterRegistry);

        return chain.filter(exchange).doOnSuccessOrError((aVoid, ex) -> {
            endTimerRespectingCommit(exchange, sample);
        });
    }

    private void endTimerRespectingCommit(ServerWebExchange exchange, Sample sample) {

        ServerHttpResponse response = exchange.getResponse();
        if (response.isCommitted()) {
            endTimerInner(exchange, sample);
        } else {
            response.beforeCommit(() -> {
                endTimerInner(exchange, sample);
                return Mono.empty();
            });
        }
    }

    private void endTimerInner(ServerWebExchange exchange, Sample sample) {
        String outcome = "CUSTOM";
        String status = "CUSTOM";
        HttpStatus statusCode = exchange.getResponse().getStatusCode();
        if (statusCode != null) {
            outcome = statusCode.series().name();
            status = statusCode.name();
        } else { // a non standard HTTPS status could be used. Let's be defensive here
            if (exchange.getResponse() instanceof AbstractServerHttpResponse) {
                Integer statusInt = ((AbstractServerHttpResponse) exchange.getResponse()).getStatusCodeValue();
                if (statusInt != null) {
                    status = String.valueOf(statusInt);
                } else {
                    status = "NA";
                }
            }
        }
        Route route = exchange.getAttribute(GATEWAY_ROUTE_ATTR);
        Tags tags = Tags.of("outcome", outcome, "status", status, "routeId", route.getId(), "routeUri",
                route.getUri().toString());
        if (log.isTraceEnabled()) {
            log.trace("Stopping timer 'gateway.requests' with tags " + tags);
        }
        sample.stop(meterRegistry.timer("gateway.requests", tags));
    }

}