fix: HTTP/1 active-request metrics leak when response ends before request body completes

vertx-core/src/main/java/io/vertx/core/http/impl/http1/Http1ServerConnection.java

@@ -513,6 +513,14 @@ protected void handleClosed() {
     if (responseInProgress != null) {
       responseInProgress.handleException(HttpUtils.CONNECTION_CLOSED_EXCEPTION);
     }
+    Http1ServerRequest requestInProgress = this.requestInProgress;
+    if (requestInProgress != null && requestInProgress != responseInProgress && !requestInProgress.isEnded()) {
+      // The request body was not fully received before the connection closed,
+      // report a request reset so metrics like active requests are not leaked
+      if (httpMetrics != null) {
+        httpMetrics.requestReset(requestInProgress.metric());
+      }
+    }
     super.handleClosed();
   }
 

vertx-core/src/test/java/io/vertx/tests/metrics/Http1xMetricsLeakTest.java

@@ -0,0 +1,72 @@
+/*
+ * Copyright (c) 2011-2019 Contributors to the Eclipse Foundation
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License 2.0 which is available at
+ * http://www.eclipse.org/legal/epl-2.0, or the Apache License, Version 2.0
+ * which is available at https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR Apache-2.0
+ */
+package io.vertx.tests.metrics;
+
+import io.vertx.core.ThreadingModel;
+import io.vertx.core.http.HttpVersion;
+import io.vertx.test.fakemetrics.FakeHttpServerMetrics;
+import io.vertx.test.fakemetrics.FakeMetricsBase;
+import io.vertx.test.fakemetrics.HttpServerMetric;
+import io.vertx.test.http.HttpConfigurator;
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.net.Socket;
+import java.util.concurrent.atomic.AtomicReference;
+
+/**
+ * Tests for the HTTP/1 active-request metrics leak fixed in #6329.
+ *
+ * When the server ends the response before the request body is complete and the
+ * client then closes the connection without sending the remaining body, the
+ * request metric must be reset (requestReset) instead of leaking forever.
+ */
+public class Http1xMetricsLeakTest extends HttpMetricsTestBase {
+
+  public Http1xMetricsLeakTest() {
+    super(HttpConfigurator.Http1x.DEFAULT, HttpVersion.HTTP_1_1, ThreadingModel.EVENT_LOOP);
+  }
+
+  @Test
+  public void testActiveRequestResetWhenConnectionClosesBeforeRequestBody() throws Exception {
+    AtomicReference<HttpServerMetric> metricRef = new AtomicReference<>();
+    server.requestHandler(req -> {
+      FakeHttpServerMetrics metrics = FakeMetricsBase.httpMetricsOf(server);
+      HttpServerMetric metric = metrics.getRequestMetric(req);
+      Assert.assertNotNull(metric);
+      metricRef.set(metric);
+      // Early response: end before the request body is consumed
+      req.response().setStatusCode(401).end();
+    });
+    startServer(testAddress);
+
+    // Send a GET with Content-Length: 1 but close the connection without sending the body byte
+    try (Socket socket = new Socket("127.0.0.1", testAddress.port())) {
+      socket.setSoTimeout(2000);
+      socket.getOutputStream().write((
+        "GET / HTTP/1.1\r\n" +
+        "Host: 127.0.0.1\r\n" +
+        "Content-Length: 1\r\n" +
+        "Connection: keep-alive\r\n" +
+        "\r\n"
+      ).getBytes());
+      socket.getOutputStream().flush();
+      // Read the early 401 response then close without sending the declared body byte
+      while (socket.getInputStream().read() >= 0) {
+        // consume
+      }
+    }
+
+    // The request body was never completed, so requestReset must have been
+    // reported and the metric must be marked as failed (i.e. removed/reset)
+    assertWaitUntil(() -> metricRef.get() != null && metricRef.get().failed.get());
+  }
+}