SpringCloud Gateway 請求響應日志

請求響應日志是日常開發調試定位問題的重要手段，在微服務中引入SpringCloud Gateway後我們希望在網關層統一進行日志的收集。

本節内容将實作以下兩個功能：

擷取請求的輸入輸出參數，封裝成自定義日志

将日志發送到MongoDB進行存儲

擷取輸入輸出參數

首先我們先定義一個日志體

@Data

public class GatewayLog {

/*通路執行個體/

private String targetServer;

/*請求路徑/

private String requestPath;

/*請求方法/

private String requestMethod;

/**協定 */

private String schema;

/*請求體/

private String requestBody;

/*響應體/

private String responseData;

/*請求ip/

private String ip;

/*請求時間/

private Date requestTime;

/響應時間/

private Date responseTime;

/執行時間/

private long executeTime;

}

【關鍵】在網關定義日志過濾器，擷取輸入輸出參數

/

• 日志過濾器，用于記錄日志
• @author

• @date

  */

  @Slf4j

  @Component

  public class AccessLogFilter implements GlobalFilter, Ordered {

  @Autowired

  private AccessLogService accessLogService;

  private final List<HttpMessageReader<?>> messageReaders = HandlerStrategies.withDefaults().messageReaders();

  @Override

  public int getOrder() {

  return -100;

  @SuppressWarnings(“unchecked”)

  public Mono filter(ServerWebExchange exchange, GatewayFilterChain chain) {

  ServerHttpRequest request = exchange.getRequest();
  
   // 請求路徑
   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<String, String> queryParams = exchange.getRequest().getQueryParams();

  for (Map.Entry<String, List> entry : queryParams.entrySet()) {

  builder.append(entry.getKey()).append("=").append(StringUtils.join(entry.getValue(), “,”));

  accessLog.setRequestBody(builder.toString());

  //擷取響應體
   ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, accessLog);
  
   return chain.filter(exchange.mutate().response(decoratedResponse).build())
           .then(Mono.fromRunnable(() -> {
               // 列印日志
               writeAccessLog(accessLog);
           }));
             

  /**
  • 解決 request body 隻能讀取一次問題，
  • 參考: org.springframework.cloud.gateway.filter.factory.rewrite.ModifyRequestBodyGatewayFilterFactory
  • @param exchange
  • @param chain
  • @param gatewayLog

  • @return

    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);

    });

    // 通過 BodyInserter 插入 body(支援修改body), 避免 request body 隻能擷取一次

    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(() -> {

    // 重新封裝請求

    ServerHttpRequest decoratedRequest = requestDecorate(exchange, headers, outputMessage);

    // 記錄響應日志
             ServerHttpResponseDecorator decoratedResponse = recordResponseLog(exchange, gatewayLog);
    
             // 記錄普通的
             return chain.filter(exchange.mutate().request(decoratedRequest).response(decoratedResponse).build())
                     .then(Mono.fromRunnable(() -> {
                         // 列印日志
                         writeAccessLog(gatewayLog);
                     }));
         }));
               

  • 列印日志

  • @param gatewayLog 網關日志

    private void writeAccessLog(GatewayLog gatewayLog) {

    log.info(gatewayLog.toString());

  private Route getGatewayRoute(ServerWebExchange exchange) {

  return exchange.getAttribute(ServerWebExchangeUtils.GATEWAY_ROUTE_ATTR);

  • 請求裝飾器，重新計算 headers
  • @param headers
  • @param outputMessage

  • 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<DataBuffer> getBody() {
         return outputMessage.getBody();
     }
               

    };
  • 記錄響應日志

  • 通過 DataBufferFactory 解決響應體分段傳輸問題。

    private ServerHttpResponseDecorator recordResponseLog(ServerWebExchange exchange, GatewayLog gatewayLog) {

    ServerHttpResponse response = exchange.getResponse();

    DataBufferFactory bufferFactory = response.bufferFactory();

    return new ServerHttpResponseDecorator(response) {

    public Mono writeWith(Publisher<? extends DataBuffer> body) {

    if (body instanceof Flux) {

    Date responseTime = new Date();

    gatewayLog.setResponseTime(responseTime);

    // 計算執行時間

    long executeTime = (responseTime.getTime() - gatewayLog.getRequestTime().getTime());

    gatewayLog.setExecuteTime(executeTime);
    
             // 擷取響應類型，如果是 json 就列印
             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<? extends DataBuffer> fluxBody = Flux.from(body);
                 return super.writeWith(fluxBody.buffer().map(dataBuffers -> {
    
                     // 合并多個流集合，解決傳回體分段傳輸
                     DataBufferFactory dataBufferFactory = new DefaultDataBufferFactory();
                     DataBuffer join = dataBufferFactory.join(dataBuffers);
                     byte[] content = new byte[join.readableByteCount()];
                     join.read(content);
    
                     // 釋放掉記憶體
                     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);
     }
               

    代碼較長建議直接拷貝到編輯器，隻要注意下面一個關鍵點：

getOrder()方法傳回的值必須要<-1，「否則标準的NettyWriteResponseFilter将在您的過濾器被調用的機會之前發送響應，即不會執行擷取後端響應參數的方法」

通過上面的兩步我們已經可以擷取到請求的輸入輸出參數了，在 writeAccessLog()中将其輸出到了日志檔案，大家可以在Postman發送請求觀察日志。

存儲日志

如果需要将日志持久化友善後期檢索的話可以考慮将日志存儲在MongoDB中，實作過程很簡單。（安裝MongoDB可以參考這篇文章：實戰|MongoDB的安裝配置）

引入MongoDB

org.springframework.boot

spring-boot-starter-data-mongodb-reactive

由于gateway是基于webflux，是以我們需要選擇reactive版本。

在GatewayLog上添加對應的注解

@Document

@Id

private String id;

…

建立AccessLogRepository

@Repository

public interface AccessLogRepository extends ReactiveMongoRepository<GatewayLog,String> {

/**
 * 儲存AccessLog
 * @param gatewayLog 請求響應日志
 * @return 響應日志
 */
Mono<GatewayLog> saveAccessLog(GatewayLog gatewayLog);
           

@Override
public Mono<GatewayLog> saveAccessLog(GatewayLog gatewayLog) {
    return accessLogRepository.insert(gatewayLog);
}