从零搭建Spring Cloud Gateway网关（二）—— 打印请求响应日志

作为网关，日志记录是必不可少的功能，可以在网关出增加requestId来查询整个请求链的调用执行情况等等。

打印请求日志

打印请求日志最重要的就是打印请求参数这些东西，不过RequestBody通常情况下在被读取一次之后就会失效，这样的话，下游的服务就不能正常获取到请求参数了。所以我们需要重写下请求体。

具体方法呢有很多，这里说一下我用的两种：

第一种

代码如下：

package com.lifengdi.gateway.filter;

import com.lifengdi.gateway.constant.HeaderConstant;
import com.lifengdi.gateway.constant.OrderedConstant;
import com.lifengdi.gateway.log.Log;
import com.lifengdi.gateway.log.LogHelper;
import com.lifengdi.gateway.utils.GenerateIdUtils;
import com.lifengdi.gateway.utils.IpUtils;
import io.netty.buffer.UnpooledByteBufAllocator;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.stereotype.Component;
import org.springframework.util.StopWatch;
import org.springframework.web.reactive.function.server.HandlerStrategies;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.net.URI;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicReference;
import java.util.function.Consumer;

/**
 * 请求日志打印
 */
@Component
@Slf4j
public class RequestLogFilter implements GlobalFilter, Ordered {

    @Override
    public int getOrder() {
        return OrderedConstant.REQUEST_FILTER;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        StopWatch stopWatch = new StopWatch();
        stopWatch.start();
        long startTime = System.currentTimeMillis();
        try {
            ServerHttpRequest request = exchange.getRequest();
            // 设置X-Request-Id
            AtomicReference<String> requestId = new AtomicReference<>(GenerateIdUtils.requestIdWithUUID());
            Consumer<HttpHeaders> httpHeadersConsumer = httpHeaders -> {
                String headerRequestId = request.getHeaders().getFirst(HeaderConstant.REQUEST_ID);
                if (StringUtils.isBlank(headerRequestId)) {
                    httpHeaders.set(HeaderConstant.REQUEST_ID, requestId.get());
                } else {
                    requestId.set(headerRequestId);
                }
                httpHeaders.set(HeaderConstant.START_TIME_KEY, String.valueOf(startTime));
            };
            ServerRequest serverRequest = ServerRequest.create(exchange,
                    HandlerStrategies.withDefaults().messageReaders());
            URI requestUri = request.getURI();
            String uriQuery = requestUri.getQuery();
            String url = requestUri.getPath() + (StringUtils.isNotBlank(uriQuery) ? "?" + uriQuery : "");
            HttpHeaders headers = request.getHeaders();
            MediaType mediaType = headers.getContentType();
            String method = request.getMethodValue().toUpperCase();

            // 原始请求体
            final AtomicReference<String> requestBody = new AtomicReference<>();
            final AtomicBoolean newBody = new AtomicBoolean(false);
            if (Objects.nonNull(mediaType) && LogHelper.isUploadFile(mediaType)) {
                requestBody.set("上传文件");
            } else {
                if (method.equals("GET")) {
                    if (StringUtils.isNotBlank(uriQuery)) {
                        requestBody.set(uriQuery);
                    }
                } else {
                    newBody.set(true);
                }
            }
            final Log logDTO = new Log();
            logDTO.setLevel(Log.LEVEL.INFO);
            logDTO.setRequestUrl(url);
            logDTO.setRequestBody(requestBody.get());
            logDTO.setRequestMethod(method);
            logDTO.setRequestId(requestId.get());
            logDTO.setIp(IpUtils.getClientIp(request));

            ServerHttpRequest serverHttpRequest = exchange.getRequest().mutate().headers(httpHeadersConsumer).build();
            ServerWebExchange build = exchange.mutate().request(serverHttpRequest).build();
            return build.getSession().flatMap(webSession -> {
                logDTO.setSessionId(webSession.getId());
                if (newBody.get() && headers.getContentLength() > 0) {
                    Mono<String> bodyToMono = serverRequest.bodyToMono(String.class);
                    return bodyToMono.flatMap(reqBody -> {
                        logDTO.setRequestBody(reqBody);
                        // 重写原始请求
                        ServerHttpRequestDecorator requestDecorator = new ServerHttpRequestDecorator(exchange.getRequest()) {
                            @Override
                            public Flux<DataBuffer> getBody() {
                                NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(new UnpooledByteBufAllocator(false));
                                DataBuffer bodyDataBuffer = nettyDataBufferFactory.wrap(reqBody.getBytes());
                                return Flux.just(bodyDataBuffer);
                            }
                        };
                        return chain.filter(exchange.mutate()
                                .request(requestDecorator)
                                .build()).then(LogHelper.doRecord(logDTO));
                    });
                } else {
                    return chain.filter(exchange).then(LogHelper.doRecord(logDTO));
                }
            });

        } catch (Exception e) {
            log.error("请求日志打印出现异常", e);
            return chain.filter(exchange);
        }
    }

}

上面的核心代码是：

// 重写原始请求
ServerHttpRequestDecorator requestDecorator = new ServerHttpRequestDecorator(exchange.getRequest()) {
    @Override
    public Flux<DataBuffer> getBody() {
        NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(new UnpooledByteBufAllocator(false));
        DataBuffer bodyDataBuffer = nettyDataBufferFactory.wrap(reqBody.getBytes());
        return Flux.just(bodyDataBuffer);
    }
};
return chain.filter(exchange.mutate()
        .request(requestDecorator)
        .build()).then(LogHelper.doRecord(logDTO));

如果不需要对session进行操作，可以直接调用这块就行。

关于请求时间，我这里采用的是将时间戳放进请求头中，等到打印日志的时候再从请求头中读取然后计算出时间。否则如果单独在某个filter中计算请求时间，会造成时间不太准确。当然这样时间也不是很准确，毕竟还有Spring本身的filter等业务逻辑，不过时间相差不是很大，大概十几毫秒的样子。

第二种

第二种就是自己缓存下请求体，读取的时候读取缓存内容。

代码如下：

package com.lifengdi.gateway.log;

import com.lifengdi.gateway.constant.HeaderConstant;
import com.lifengdi.gateway.utils.IpUtils;
import io.netty.buffer.UnpooledByteBufAllocator;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.io.IOUtils;
import org.apache.commons.lang.StringUtils;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import reactor.core.publisher.Flux;
import reactor.core.scheduler.Schedulers;

import java.io.IOException;
import java.io.InputStream;
import java.net.URI;
import java.util.Objects;

/**
 * 对ServerHttpRequest进行二次封装，解决requestBody只能读取一次的问题
 * @author: Li Fengdi
 * @date: 2020-03-17 18:02
 */
@Slf4j
public class CacheServerHttpRequestDecorator extends ServerHttpRequestDecorator {
    private DataBuffer bodyDataBuffer;
    private int getBufferTime = 0;
    private byte[] bytes;

    public CacheServerHttpRequestDecorator(ServerHttpRequest delegate) {
        super(delegate);
    }

    @Override
    public Flux<DataBuffer> getBody() {
        if (getBufferTime == 0) {
            getBufferTime++;
            Flux<DataBuffer> flux = super.getBody();
            return flux.publishOn(Schedulers.single())
                    .map(this::cache)
                    .doOnComplete(() -> trace(getDelegate()));

        } else {
            return Flux.just(getBodyMore());
        }

    }


    private DataBuffer getBodyMore() {
        NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(new UnpooledByteBufAllocator(false));
        bodyDataBuffer = nettyDataBufferFactory.wrap(bytes);
        return bodyDataBuffer;
    }

    private DataBuffer cache(DataBuffer buffer) {
        try {
            InputStream dataBuffer = buffer.asInputStream();
            bytes = IOUtils.toByteArray(dataBuffer);
            NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(new UnpooledByteBufAllocator(false));
            bodyDataBuffer = nettyDataBufferFactory.wrap(bytes);
            return bodyDataBuffer;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return null;
    }

    private void trace(ServerHttpRequest request) {
        URI requestUri = request.getURI();
        String uriQuery = requestUri.getQuery();
        String url = requestUri.getPath() + (StringUtils.isNotBlank(uriQuery) ? "?" + uriQuery : "");
        HttpHeaders headers = request.getHeaders();
        MediaType mediaType = headers.getContentType();
        String schema = requestUri.getScheme();
        String method = request.getMethodValue().toUpperCase();
        if ((!"http".equals(schema) && !"https".equals(schema))) {
            return;
        }
        String reqBody = null;
        if (Objects.nonNull(mediaType) && LogHelper.isUploadFile(mediaType)) {
            reqBody = "上传文件";
        } else {
            if (method.equals("GET")) {
                if (StringUtils.isNotBlank(uriQuery)) {
                    reqBody = uriQuery;
                }
            } else if (headers.getContentLength() > 0) {
                reqBody = LogHelper.readRequestBody(request);
            }
        }
        final Log logDTO = new Log();
        logDTO.setLevel(Log.LEVEL.INFO);
        logDTO.setRequestUrl(url);
        logDTO.setRequestBody(reqBody);
        logDTO.setRequestMethod(method);
        logDTO.setRequestId(headers.getFirst(HeaderConstant.REQUEST_ID));
        logDTO.setIp(IpUtils.getClientIp(request));
        log.info(LogHelper.toJsonString(logDTO));
    }

}

filter这里就简单写下：

package com.lifengdi.gateway.filter;

import com.lifengdi.gateway.constant.OrderedConstant;
import com.lifengdi.gateway.log.CacheServerHttpRequestDecorator;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Mono;

/**
 * @author: Li Fengdi
 * @date: 2020-03-17 18:17
 */
//@Component
public class LogFilter implements GlobalFilter, Ordered {
    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        CacheServerHttpRequestDecorator cacheServerHttpRequestDecorator = new CacheServerHttpRequestDecorator(exchange.getRequest());

        return chain.filter(exchange.mutate().request(cacheServerHttpRequestDecorator).build());
    }

    @Override
    public int getOrder() {
        return OrderedConstant.LOGGING_FILTER;
    }
}

工具类也贴下：

package com.lifengdi.gateway.log;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.lifengdi.gateway.constant.HeaderConstant;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.lang.NonNull;
import org.springframework.lang.Nullable;
import reactor.core.publisher.Mono;

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;

@Slf4j
public class LogHelper {

    private final static ObjectMapper objectMapper = new ObjectMapper();

    /**
     * Log转JSON
     * @param dto Log
     * @return JSON字符串
     */
    public static String toJsonString(@NonNull Log dto) {
        try {
            return objectMapper.writeValueAsString(dto);
        } catch (JsonProcessingException e) {
            log.error("Log转换JSON异常", e);
            return null;
        }
    }

    /**
     * 根据MediaType获取字符集，如果获取不到，则默认返回<tt>UTF_8</tt>
     * @param mediaType MediaType
     * @return Charset
     */
    public static Charset getMediaTypeCharset(@Nullable MediaType mediaType) {
        if (Objects.nonNull(mediaType) && mediaType.getCharset() != null) {
            return mediaType.getCharset();
        } else {
            return StandardCharsets.UTF_8;
        }
    }

    /**
     * 记录日志（后期可扩展为通过MQ将日志发送到ELK系统）
     * @param dto Log
     * @return Mono.empty()
     */
    public static Mono<Void> doRecord(Log dto) {
        log.info(toJsonString(dto));
        return Mono.empty();
    }

    /**
     * 从HttpHeaders获取请求开始时间
     * <p>
     *     要求请求头中必须要有参数{@link HeaderConstant#START_TIME_KEY}，否则将返回当前时间戳
     * </p>
     * @param headers HttpHeaders请求头
     * @return 开始时间时间戳（Mills）
     */
    public static long getStartTime(HttpHeaders headers) {
        String startTimeStr = headers.getFirst(HeaderConstant.START_TIME_KEY);
        return StringUtils.isNotBlank(startTimeStr) ? Long.parseLong(startTimeStr) : System.currentTimeMillis();
    }

    /**
     * 根据HttpHeaders请求头获取请求执行时间
     * <p>
     *     要求请求头中必须要有参数{@link HeaderConstant#START_TIME_KEY}
     * </p>
     * @param headers HttpHeaders请求头
     * @return 请求执行时间
     */
    public static long getHandleTime(HttpHeaders headers) {
        String startTimeStr = headers.getFirst(HeaderConstant.START_TIME_KEY);
        long startTime = StringUtils.isNotBlank(startTimeStr) ? Long.parseLong(startTimeStr) : System.currentTimeMillis();
        return System.currentTimeMillis() - startTime;
    }

    /**
     * 读取请求体内容
     * @param request ServerHttpRequest
     * @return 请求体
     */
    public static String readRequestBody(ServerHttpRequest request) {
        HttpHeaders headers = request.getHeaders();
        MediaType mediaType = headers.getContentType();
        String method = request.getMethodValue().toUpperCase();
        if (Objects.nonNull(mediaType) && mediaType.equals(MediaType.MULTIPART_FORM_DATA)) {
            return "上传文件";
        } else {
            if (method.equals("GET")) {
                if (!request.getQueryParams().isEmpty()) {
                    return request.getQueryParams().toString();
                }
                return null;
            } else {
                AtomicReference<String> bodyString = new AtomicReference<>();
                request.getBody().subscribe(buffer -> {
                    byte[] bytes = new byte[buffer.readableByteCount()];
                    buffer.read(bytes);
                    DataBufferUtils.release(buffer);
                    bodyString.set(new String(bytes, getMediaTypeCharset(mediaType)));
                });
                return bodyString.get();
            }
        }
    }

    /**
     * 判断是否是上传文件
     * @param mediaType MediaType
     * @return Boolean
     */
    public static boolean isUploadFile(@Nullable MediaType mediaType) {
        if (Objects.isNull(mediaType)) {
            return false;
        }
        return mediaType.equals(MediaType.MULTIPART_FORM_DATA)
                || mediaType.equals(MediaType.IMAGE_GIF)
                || mediaType.equals(MediaType.IMAGE_JPEG)
                || mediaType.equals(MediaType.IMAGE_PNG)
                || mediaType.equals(MediaType.MULTIPART_MIXED);
    }
}

打印响应报文

响应报文需要在Spring重写了响应体之后才能获取到，所以对filter的执行顺序有要求，需要在
NettyWriteResponseFilter.WRITE_RESPONSE_FILTER_ORDER之前执行。代码如下：

package com.lifengdi.gateway.filter;

import com.lifengdi.gateway.constant.HeaderConstant;
import com.lifengdi.gateway.constant.OrderedConstant;
import com.lifengdi.gateway.log.Log;
import com.lifengdi.gateway.log.LogHelper;
import com.lifengdi.gateway.utils.IpUtils;
import io.netty.buffer.UnpooledByteBufAllocator;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang.StringUtils;
import org.reactivestreams.Publisher;
import org.springframework.cloud.gateway.filter.GatewayFilterChain;
import org.springframework.cloud.gateway.filter.GlobalFilter;
import org.springframework.core.Ordered;
import org.springframework.core.io.buffer.DataBuffer;
import org.springframework.core.io.buffer.DataBufferFactory;
import org.springframework.core.io.buffer.DataBufferUtils;
import org.springframework.core.io.buffer.NettyDataBufferFactory;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.server.reactive.ServerHttpRequest;
import org.springframework.http.server.reactive.ServerHttpRequestDecorator;
import org.springframework.http.server.reactive.ServerHttpResponse;
import org.springframework.http.server.reactive.ServerHttpResponseDecorator;
import org.springframework.stereotype.Component;
import org.springframework.web.reactive.function.server.HandlerStrategies;
import org.springframework.web.reactive.function.server.ServerRequest;
import org.springframework.web.server.ServerWebExchange;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;

import java.net.URI;
import java.nio.charset.Charset;
import java.util.Objects;
import java.util.concurrent.atomic.AtomicReference;

/**
 * 请求响应日志打印
 */
@Component
@Slf4j
public class ResponseLogFilter implements GlobalFilter, Ordered {

    @Override
    public int getOrder() {
        return OrderedConstant.LOGGING_FILTER;
    }

    @Override
    public Mono<Void> filter(ServerWebExchange exchange, GatewayFilterChain chain) {
        try {
            ServerHttpRequest request = exchange.getRequest();
            ServerRequest serverRequest = ServerRequest.create(exchange,
                    HandlerStrategies.withDefaults().messageReaders());
            URI requestUri = request.getURI();
            String uriQuery = requestUri.getQuery();
            HttpHeaders headers = request.getHeaders();
            MediaType mediaType = headers.getContentType();
            String schema = requestUri.getScheme();
            String method = request.getMethodValue().toUpperCase();

            // 只记录http、https请求
            if ((!"http".equals(schema) && !"https".equals(schema))) {
                return chain.filter(exchange);
            }
            final AtomicReference<String> requestBody = new AtomicReference<>();// 原始请求体
            // 排除流文件类型,比如上传的文件contentType.contains("multipart/form-data")
            if (Objects.nonNull(mediaType) && LogHelper.isUploadFile(mediaType)) {
                requestBody.set("上传文件");
                return chain.filter(exchange);
            } else {
                if (method.equals("GET")) {
                    if (StringUtils.isNotBlank(uriQuery)) {
                        requestBody.set(uriQuery);
                    }
                } else if (headers.getContentLength() > 0){
                    return serverRequest.bodyToMono(String.class).flatMap(reqBody -> {
                        requestBody.set(reqBody);
                        // 重写原始请求
                        ServerHttpRequestDecorator requestDecorator = new ServerHttpRequestDecorator(exchange.getRequest()) {
                            @Override
                            public HttpHeaders getHeaders() {
                                HttpHeaders httpHeaders = new HttpHeaders();
                                httpHeaders.putAll(super.getHeaders());
                                return httpHeaders;
                            }

                            @Override
                            public Flux<DataBuffer> getBody() {
                                NettyDataBufferFactory nettyDataBufferFactory = new NettyDataBufferFactory(new UnpooledByteBufAllocator(false));
                                DataBuffer bodyDataBuffer = nettyDataBufferFactory.wrap(reqBody.getBytes());
                                return Flux.just(bodyDataBuffer);
//                                return Flux.just(reqBody).map(bx -> exchange.getRequest().bufferFactory().wrap(bx.getBytes()));
                            }
                        };
                        ServerHttpResponseDecorator responseDecorator = getServerHttpResponseDecorator(exchange,
                                requestBody);
                        return chain.filter(exchange.mutate()
                                .request(requestDecorator)
                                .response(responseDecorator)
                                .build());
                    });
                }
                ServerHttpResponseDecorator decoratedResponse = getServerHttpResponseDecorator(exchange,
                        requestBody);
                return chain.filter(exchange.mutate()
                        .response(decoratedResponse)
                        .build());
            }

        } catch (Exception e) {
            log.error("请求响应日志打印出现异常", e);
            return chain.filter(exchange);
        }

    }

    private ServerHttpResponseDecorator getServerHttpResponseDecorator(ServerWebExchange exchange,
                                                                       AtomicReference<String> requestBody) {
        // 获取response的返回数据
        ServerHttpResponse originalResponse = exchange.getResponse();
        DataBufferFactory bufferFactory = originalResponse.bufferFactory();
        HttpStatus httpStatus = originalResponse.getStatusCode();
        ServerHttpRequest request = exchange.getRequest();
        URI requestUri = request.getURI();
        String uriQuery = requestUri.getQuery();
        String url = requestUri.getPath() + (StringUtils.isNotBlank(uriQuery) ? "?" + uriQuery : "");
        HttpHeaders headers = request.getHeaders();
        String method = request.getMethodValue().toUpperCase();
        String requestId = headers.getFirst(HeaderConstant.REQUEST_ID);

        // 封装返回体
        return new ServerHttpResponseDecorator(originalResponse) {
            @Override
            public Mono<Void> writeWith(Publisher<? extends DataBuffer> body) {
                if (body instanceof Flux) {
                    Flux<? extends DataBuffer> fluxBody = Flux.from(body);
                    return super.writeWith(fluxBody.buffer().map(dataBuffers -> {
                        DataBuffer join = bufferFactory.join(dataBuffers);
                        byte[] content = new byte[join.readableByteCount()];
                        join.read(content);
                        DataBufferUtils.release(join);
                        Charset charset = LogHelper.getMediaTypeCharset(originalResponse.getHeaders().getContentType());
                        String responseBody = new String(content, charset);

                        long handleTime = LogHelper.getHandleTime(headers);
                        Log logDTO = new Log(Log.TYPE.RESPONSE);
                        logDTO.setLevel(Log.LEVEL.INFO);
                        logDTO.setRequestUrl(url);
                        logDTO.setRequestBody(requestBody.get());
                        logDTO.setResponseBody(responseBody);
                        logDTO.setRequestMethod(method);
                        if (Objects.nonNull(httpStatus)) {
                            logDTO.setStatus(httpStatus.value());
                        }
                        logDTO.setHandleTime(handleTime);
                        logDTO.setRequestId(requestId);
                        logDTO.setIp(IpUtils.getClientIp(request));
                        exchange.getSession().subscribe(webSession -> {
                            logDTO.setSessionId(webSession.getId());
                        });

                        log.info("url:{},method:{},请求内容:{},响应内容:{},status:{},handleTime:{},requestId:{}",
                                url, method, requestBody.get(), responseBody, httpStatus,
                                handleTime, requestId);
                        log.info(LogHelper.toJsonString(logDTO));
                        return bufferFactory.wrap(content);
                    }));
                }
                return super.writeWith(body);
            }
        };
    }

}

代码已上传到git上，需要的可以去看看。

git代码地址：https://github.com/lifengdi/spring-cloud-gateway-demo

原文地址：https://www.lifengdi.com/archives/article/1778