[KYUUBI #6615] Make Jetty sending server version in response configur…

…able

# 🔍 Description
## Issue References 🔗

This pull request fixes #6615

## Describe Your Solution 🔧

Add a config item that controls whether Jetty should send its version in response.

This is an additional patch which enables/disables sending Jetty version for  prometheus reporter.

Sending Jetty version could be disabled by calling HttpConfiguration::setSendServerVersion(false)

## Types of changes 🔖

- [x] Bugfix (non-breaking change which fixes an issue)
- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

## Test Plan 🧪

Compiled and tested manually.

#### Behavior Without This Pull Request ⚰️

#### Behavior With This Pull Request 🎉

#### Related Unit Tests

---

# Checklist 📝

- [ ] This patch was not authored or co-authored using [Generative Tooling](https://www.apache.org/legal/generative-tooling.html)

**Be nice. Be informative.**

Closes #6685 from paul8263/KYUUBI-6615-patch.

Closes #6615

0638a51 [zhang_yao] [KYUUBI #6615] Make Jetty sending server version in response configurable

Authored-by: zhang_yao <xzhangyao@126.com>
Signed-off-by: Cheng Pan <chengpan@apache.org>

kyuubi-metrics/src/main/scala/org/apache/kyuubi/metrics/PrometheusReporterService.scala

@@ -21,11 +21,12 @@ import com.codahale.metrics.MetricRegistry
 import io.prometheus.client.CollectorRegistry
 import io.prometheus.client.dropwizard.DropwizardExports
 import io.prometheus.client.exporter.MetricsServlet
-import org.eclipse.jetty.server.Server
+import org.eclipse.jetty.server.{HttpConfiguration, HttpConnectionFactory, Server, ServerConnector}
 import org.eclipse.jetty.servlet.{ServletContextHandler, ServletHolder}
 
 import org.apache.kyuubi.KyuubiException
 import org.apache.kyuubi.config.KyuubiConf
+import org.apache.kyuubi.config.KyuubiConf.FRONTEND_JETTY_SEND_VERSION_ENABLED
 import org.apache.kyuubi.service.AbstractService
 
 class PrometheusReporterService(registry: MetricRegistry)
@@ -35,12 +36,21 @@ class PrometheusReporterService(registry: MetricRegistry)
 
   // VisibleForTesting
   private[metrics] var httpServer: Server = _
+  private[metrics] var httpServerConnector: ServerConnector = _
   @volatile protected var isStarted = false
 
   override def initialize(conf: KyuubiConf): Unit = {
     val port = conf.get(MetricsConf.METRICS_PROMETHEUS_PORT)
     val contextPath = conf.get(MetricsConf.METRICS_PROMETHEUS_PATH)
-    httpServer = new Server(port)
+    val jettyVersionEnabled = conf.get(FRONTEND_JETTY_SEND_VERSION_ENABLED)
+
+    val httpConf = new HttpConfiguration()
+    httpConf.setSendServerVersion(jettyVersionEnabled)
+    httpServer = new Server()
+    httpServerConnector = new ServerConnector(httpServer, new HttpConnectionFactory(httpConf))
+    httpServerConnector.setPort(port)
+    httpServer.addConnector(httpServerConnector)
+
     val context = new ServletContextHandler
     context.setContextPath("/")
     httpServer.setHandler(context)
@@ -56,6 +66,7 @@ class PrometheusReporterService(registry: MetricRegistry)
     if (!isStarted) {
       try {
         httpServer.start()
+        httpServerConnector.start()
         info(s"Prometheus metrics HTTP server has started at ${httpServer.getURI}.")
       } catch {
         case rethrow: Exception =>
@@ -78,12 +89,14 @@ class PrometheusReporterService(registry: MetricRegistry)
   private def stopHttpServer(): Unit = {
     if (httpServer != null) {
       try {
+        httpServerConnector.stop()
         httpServer.stop()
         info("Prometheus metrics HTTP server has stopped.")
       } catch {
         case err: Exception => error("Cannot safely stop prometheus metrics HTTP server", err)
       } finally {
         httpServer = null
+        httpServerConnector = null
       }
     }
   }