High-Entropy VS Low-Entropy in Spring Cloud Gateway

HighEntropy.kt

@Configuration
@Profile("routes-filter")
class FilterConfiguration {
  companion object {
    private val log = Loggers.getLogger(FilterConfiguration::class.java)
  }

  @Bean
  fun filterGateway(builder: RouteLocatorBuilder): RouteLocator =
    builder.routes()
      .route { spec ->
        spec.path("/")
          .filters { fs ->
            fs.setPath("/forms/post")
              .retry(10)
              .addRequestParameter("uid", UUID.randomUUID().toString())
              .addResponseHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*")
              .filter { exchange, chain ->
                val uri = exchange.request.uri
                chain.filter(exchange)
                  .doOnSubscribe { _ -> log.info("Before: $uri") }
                  .doOnEach { _ -> log.info("Processing: $uri") }
                  .doOnTerminate { log.info("After: $uri") }
              }
          }
          .uri("https://httpbin.org")
      }.build()
}

LowEntropy.kt

@Configuration
@Profile("routes-filter")
class FilterConfiguration {
  companion object {
    private val log = Loggers.getLogger(FilterConfiguration::class.java)
  }

  @Bean
  fun filterGateway(builder: RouteLocatorBuilder): RouteLocator =
    builder.routes()
      .route(::routeToFormPost)
      .build()

  private fun routeToFormPost(spec: PredicateSpec): Buildable<Route> =
    spec.path("/")
      .filters(::formPostFilters)
      .uri("https://httpbin.org")

  private fun formPostFilters(filterSpec: GatewayFilterSpec): UriSpec =
    filterSpec.setPath("/forms/post")
      .retry(10)
      .addRequestParameter("uid", UUID.randomUUID().toString())
      .addResponseHeader(HttpHeaders.ACCESS_CONTROL_ALLOW_ORIGIN, "*")
      .filter(::logRequestLifecycle)

  private fun logRequestLifecycle(exchange: ServerWebExchange, chain: GatewayFilterChain): Mono<Void> {
    val uri = exchange.request.uri

    return chain.filter(exchange)
      .doOnSubscribe(logRequestInitiation(uri))
      .doOnEach(logRequestProcessing(uri))
      .doOnTerminate(logRequestCompletion(uri, exchange))
  }

  private fun logRequestInitiation(uri: URI): (Subscription) -> Unit = { _ ->
    log.info("Before: $uri")
  }

  private fun logRequestProcessing(uri: URI): (Signal<*>) -> Unit = { _ ->
    log.info("Processing: $uri")
  }

  private fun logRequestCompletion(uri: URI, exchange: ServerWebExchange): () -> Unit = {
    log.info("After: $uri. → Status: ${exchange.response.statusCode}")
  }
}