这篇文章主要讲解了“如何实现SpringCloud Gateway请求响应日志”，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习“如何实现SpringCloud Gateway请求响应日志”吧！
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首先我们先定义一个日志体
@Data public class GatewayLog { /**访问实例*/ private String targetServer; /**请求路径*/ private String requestPath; /**请求方法*/ private String requestMethod; /**协议 */ private String schema; /**请求体*/ private String requestBody; /**响应体*/ private String responseData; /**请求ip*/ private String ip; /**请求时间*/ private Date requestTime; /**响应时间*/ private Date responseTime; /**执行时间*/ private long executeTime; }【关键】在网关定义日志过滤器，获取输入输出参数
/** * 日志过滤器，用于记录日志 * @author jianzh6 * @date 2020/3/24 17:17 */ @Slf4j @Component public class AccessLogFilter implements GlobalFilter, Ordered { @Autowired private AccessLogService accessLogService; private final List> messageReaders = HandlerStrategies.withDefaults().messageReaders(); @Override public int getOrder() { return -100; } @Override @SuppressWarnings("unchecked") public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) { ServerHttpRequest request = exchange.getRequest(); // 请求路径 String requestPath = request.getPath().pathWithinApplication().value(); Route route = getGatewayRoute(exchange); String ipAddress = WebUtils.getServerHttpRequestIpAddress(request); GatewayLog gatewayLog = new GatewayLog(); gatewayLog.setSchema(request.getURI().getScheme()); gatewayLog.setRequestMethod(request.getMethodValue()); gatewayLog.setRequestPath(requestPath); gatewayLog.setTargetServer(route.getId()); gatewayLog.setRequestTime(new Date()); gatewayLog.setIp(ipAddress); MediaType mediaType = request.getHeaders().getContentType(); if(MediaType.APPLICATION_FORM_URLENCODED.isCompatibleWith(mediaType) || MediaType.APPLICATION_JSON.isCompatibleWith(mediaType)){ return writeBodyLog(exchange, chain, gatewayLog); }else{ return writeBasicLog(exchange, chain, gatewayLog); } } private Mono writeBasicLog(ServerWebExchange exchange, GatewayFilterChain chain, GatewayLog accessLog) { StringBuilder builder = new StringBuilder(); MultiValueMap queryParams = exchange.getRequest().getQueryParams(); for (Map.Entry> entry : queryParams.entrySet()) { builder.append(entry.getKey()).append("=").append(StringUtils.join(entry.getValue(), ",")); } accessLog.setRequestBody(builder.toString()); //获取响应体 ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, accessLog); return chain.filter(exchange.mutate().response(decoratedResponse).build()) .then(Mono.fromRunnable(() -> { // 打印日志 writeAccessLog(accessLog); })); } /** * 解决 request body 只能读取一次问题， * 参考: org.springframework.cloud.gateway.filter.factory.rewrite.ModifyRequestBodyGatewayFilterFactory * @param exchange * @param chain * @param gatewayLog * @return */ @SuppressWarnings("unchecked") private Mono writeBodyLog(ServerWebExchange exchange, GatewayFilterChain chain, GatewayLog gatewayLog) { ServerRequest serverRequest = ServerRequest.create(exchange,messageReaders); Mono modifiedBody = serverRequest.bodyToMono(String.class) .flatMap(body ->{ gatewayLog.setRequestBody(body); return Mono.just(body); }); // 通过 BodyInserter 插入 body(支持修改body), 避免 request body 只能获取一次 BodyInserter bodyInserter = BodyInserters.fromPublisher(modifiedBody, String.class); HttpHeaders headers = new HttpHeaders(); headers.putAll(exchange.getRequest().getHeaders()); // the new content type will be computed by bodyInserter // and then set in the request decorator headers.remove(HttpHeaders.CONTENT_LENGTH); CachedBodyOutputMessage outputMessage = new CachedBodyOutputMessage(exchange, headers); return bodyInserter.insert(outputMessage,new BodyInserterContext()) .then(Mono.defer(() -> { // 重新封装请求 ServerHttpRequest decoratedRequest = requestDecorate(exchange, headers, outputMessage); // 记录响应日志 ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, gatewayLog); // 记录普通的 return chain.filter(exchange.mutate().request(decoratedRequest).response(decoratedResponse).build()) .then(Mono.fromRunnable(() -> { // 打印日志 writeAccessLog(gatewayLog); })); })); } /** * 打印日志 * @author javadaily * @date 2021/3/24 14:53 * @param gatewayLog 网关日志 */ private void writeAccessLog(GatewayLog gatewayLog) { log.info(gatewayLog.toString()); } private Route getGatewayRoute(ServerWebExchange exchange) { return exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR); } /** * 请求装饰器，重新计算 headers * @param exchange * @param headers * @param outputMessage * @return */ private ServerHttpRequestDecorator requestDecorate(ServerWebExchange exchange, HttpHeaders headers, CachedBodyOutputMessage outputMessage) { return new ServerHttpRequestDecorator(exchange.getRequest()) { @Override public HttpHeaders getHeaders() { long contentLength = headers.getContentLength(); HttpHeaders httpHeaders = new HttpHeaders(); httpHeaders.putAll(super.getHeaders()); if (contentLength > 0) { httpHeaders.setContentLength(contentLength); } else { // TODO: this causes a 'HTTP/1.1 411 Length Required' // on // httpbin.org httpHeaders.set(HttpHeaders.TRANSFER_ENCODING, "chunked"); } return httpHeaders; } @Override public Flux getBody() { return outputMessage.getBody(); } }; } /** * 记录响应日志 * 通过 DataBufferFactory 解决响应体分段传输问题。 */ private ServerHttpResponseDecorator recordResponseLog(ServerWebExchange exchange, GatewayLog gatewayLog) { ServerHttpResponse response = exchange.getResponse(); DataBufferFactory bufferFactory = response.bufferFactory(); return new ServerHttpResponseDecorator(response) { @Override public Mono writeWith(Publisher body) { if (body instanceof Flux) { Date responseTime = new Date(); gatewayLog.setResponseTime(responseTime); // 计算执行时间 long executeTime = (responseTime.getTime() - gatewayLog.getRequestTime().getTime()); gatewayLog.setExecuteTime(executeTime); // 获取响应类型，如果是 json 就打印 String originalResponseContentType = exchange.getAttribute(ServerWebExchangeUtils.ORIGINAL_RESPONSE_CONTENT_TYPE_ATTR); if (ObjectUtil.equal(this.getStatusCode(), HttpStatus.OK) && StringUtil.isNotBlank(originalResponseContentType) && originalResponseContentType.contains("application/json")) { Flux fluxBody = Flux.from(body); return super.writeWith(fluxBody.buffer().map(dataBuffers -> { // 合并多个流集合，解决返回体分段传输 DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory(); DataBuffer join = dataBufferFactory.join(dataBuffers); byte[] content = new byte[join.readableByteCount()]; join.read(content); // 释放掉内存 DataBufferUtils.release(join); String responseResult = new String(content, StandardCharsets.UTF_8); gatewayLog.setResponseData(responseResult); return bufferFactory.wrap(content); })); } } // if body is not a flux. never got there. return super.writeWith(body); } }; } } 代码较长建议直接拷贝到编辑器，只要注意下面一个关键点：
getOrder()方法返回的值必须要<-1，「否则标准的NettyWriteResponseFilter将在您的过滤器被调用的机会之前发送响应，即不会执行获取后端响应参数的方法」
通过上面的两步我们已经可以获取到请求的输入输出参数了，在 writeAccessLog()中将其输出到了日志文件，大家可以在Postman发送请求观察日志。
如果需要将日志持久化方便后期检索的话可以考虑将日志存储在MongoDB中，实现过程很简单。(安装MongoDB可以参考这篇文章：实战|MongoDB的安装配置)
引入MongoDB
org.springframework.boot spring-boot-starter-data-mongodb-reactive
由于gateway是基于webflux，所以我们需要选择reactive版本。
在GatewayLog上添加对应的注解
@Data @Document public class GatewayLog { @Id private String id; ... }建立AccessLogRepository
