feign日志学习记录

使用依赖

        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-openfeign</artifactId>
            <version>2.1.1.RELEASE</version>
        </dependency>

1.通过@FeignClient查看feign配置

    org.springframework.cloud.openfeign.FeignClient

    /**
	 * A custom <code>@Configuration</code> for the feign client. Can contain override
	 * <code>@Bean</code> definition for the pieces that make up the client, for instance
	 * {@link feign.codec.Decoder}, {@link feign.codec.Encoder}, {@link feign.Contract}.
	 *
	 * @see FeignClientsConfiguration for the defaults
	 * @return list of configurations for feign client
	 */
	Class<?>[] configuration() default {};

如果没有配置默认使用FeignClientsConfiguration.

	@Autowired(required = false)
	private Logger logger;

	@Bean
	@ConditionalOnMissingBean(FeignLoggerFactory.class)
	public FeignLoggerFactory feignLoggerFactory() {
		return new DefaultFeignLoggerFactory(this.logger);
	}

使用DefaultFeignLoggerFactory创建了日志

	@Override
	public Logger create(Class<?> type) {
		return this.logger != null ? this.logger : new Slf4jLogger(type);
	}

默认情况logger为空默认选用feign.slf4j.Slf4jLogger
只有logger是debug级别才会打印feign日志。

  public Slf4jLogger(Class<?> clazz) {
    this(LoggerFactory.getLogger(clazz));
  }
  @Override
  protected void logRequest(String configKey, Level logLevel, Request request) {
    // 只有类日志级别为debug才会有feign日志输出，
    if (logger.isDebugEnabled()) {
      super.logRequest(configKey, logLevel, request);
    }
  }

org.slf4j.LoggerFactory会根据类名创建logger,

    public static Logger getLogger(Class<?> clazz) {
        Logger logger = getLogger(clazz.getName());
        if (DETECT_LOGGER_NAME_MISMATCH) {
            Class<?> autoComputedCallingClass = Util.getCallingClass();
            if (autoComputedCallingClass != null && nonMatchingClasses(clazz, autoComputedCallingClass)) {
                Util.report(String.format("Detected logger name mismatch. Given name: \"%s\"; computed name: \"%s\".", logger.getName(),
                                autoComputedCallingClass.getName()));
                Util.report("See " + LOGGER_NAME_MISMATCH_URL + " for an explanation");
            }
        }
        return logger;
    }

feign请求日志feign.Logger应请求日志为例，根据不同feign日志级别打印不同信息

  protected void logRequest(String configKey, Level logLevel, Request request) {
    log(configKey, "---> %s %s HTTP/1.1", request.httpMethod().name(), request.url());
    if (logLevel.ordinal() >= Level.HEADERS.ordinal()) {

      for (String field : request.headers().keySet()) {
        for (String value : valuesOrEmpty(request.headers(), field)) {
          log(configKey, "%s: %s", field, value);
        }
      }

      int bodyLength = 0;
      if (request.body() != null) {
        bodyLength = request.body().length;
        if (logLevel.ordinal() >= Level.FULL.ordinal()) {
          String bodyText =
              request.charset() != null ? new String(request.body(), request.charset()) : null;
          log(configKey, ""); // CRLF
          log(configKey, "%s", bodyText != null ? bodyText : "Binary data");
        }
      }
      log(configKey, "---> END HTTP (%s-byte body)", bodyLength);
    }
  }

feign日志级别

  public enum Level {
    /**
     * No logging.
     */
    NONE,
    /**
     * Log only the request method and URL and the response status code and execution time.
     */
    BASIC,
    /**
     * Log the basic information along with request and response headers.
     */
    HEADERS,
    /**
     * Log the headers, body, and metadata for both requests and responses.
     */
    FULL
  }

配置class类日志级别debug，后feign日志级别生效。

logging:
  level:
    com.example.feign.client: debug  # Feign客户端所在包的日志级别
spring:
  cloud:
    openfeign:
      client:
        config:
          default:  # 全局默认配置
            loggerLevel: FULL
          hello-feign-server:  # 指定服务配置
            loggerLevel: BASIC