spark.ui.proxyBase will be overwritten each time after submit an yarn app about kyuubi HOT 7 CLOSED

// write appId
 def attachPage(page: WebUIPage): Unit = {
    val pagePath = "/" + page.prefix
    val renderHandler = createServletHandler(pagePath,
      (request: HttpServletRequest) => {
        request.setAttribute("spark.app.id", conf.get("spark.app.id"))
        page.render(request)
      }, securityManager, conf, basePath)
    val renderJsonHandler = createServletHandler(pagePath.stripSuffix("/") + "/json",
      (request: HttpServletRequest) => page.renderJson(request), securityManager, conf, basePath)
    attachHandler(renderHandler)
    attachHandler(renderJsonHandler)
    val handlers = pageToHandlers.getOrElseUpdate(page, ArrayBuffer[ServletContextHandler]())
    handlers += renderHandler
  }

// read appId
  def uiRoot(request: HttpServletRequest): String = {
    // Knox uses X-Forwarded-Context to notify the application the base path
    val knoxBasePath = Option(request.getHeader("X-Forwarded-Context"))
    // SPARK-11484 - Use the proxyBase set by the AM, if not found then use env.

    val yarnAppId = request.getAttribute("spark.app.id").asInstanceOf[String]

    logInfo(s"yarnAppId is: $yarnAppId")

    if (yarnAppId.startsWith("application_")) {
      s"/proxy/$yarnAppId"
    } else {
      sys.props.get("spark.ui.proxyBase")
        .orElse(sys.env.get("APPLICATION_WEB_PROXY_BASE"))
        .orElse(knoxBasePath)
        .getOrElse("")
    }
  }