Fix idle connection pool issue in dart:io's HttpClient

dart/tests/standalone/io/http_client_stays_alive_test.dart

+// Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:io';
+
+import "package:async_helper/async_helper.dart";
+
+// NOTE: This test tries to ensure that an HttpClient will close it's
+// underlying idle connections after [HttpClient.idleTimeout].
+//
+// The main script spawns a server and a subprocess which does a connection back
+// to it.
+// The subprocess is expected to shut down it's idle sockets after
+// [HttpClient.idleTimeout] and the main script will assert that this happens
+// within +/- 2 <= seconds.
+
+const SECONDS = 10;
+
+void runServerProcess() {
+  asyncStart();
+  HttpServer.bind('127.0.0.1', 0).then((server) {
+    var url = 'http://127.0.0.1:${server.port}/';
+
+    server.idleTimeout = const Duration(hours: 1);
+
+    var subscription = server.listen((HttpRequest request) {
+      return request.response..write('hello world')..close();
+    });
+
+    var sw = new Stopwatch()..start();
+    var arguments = ['--package-root=${Platform.packageRoot}',
+                     '${Platform.script}',
+                     url];
+    Process.run(Platform.executable, arguments).then((res) {
+      subscription.cancel();
+      if (res.exitCode != 0) {
+        throw "Child exited with ${res.exitCode} instead of 0. "
+              "(stdout: ${res.stdout}, stderr: ${res.stderr})";
+      }
+      var seconds = sw.elapsed.inSeconds;
+      // NOTE: There is a slight chance this will cause flakiness, but there is
+      // no other good way of testing correctness of timing-dependent code
+      // form the outside.
+      if ((SECONDS - seconds).abs() > 2) {
+        throw "Child did exit within $seconds seconds, but expected it to take "
+              "roughly $SECONDS seconds.";
+      }
+
+      asyncEnd();
+    });
+  });
+}
+
+void runClientProcess(String url) {
+  var uri = Uri.parse(url);
+
+  // NOTE: We make an HTTP client request and then *forget to close* the HTTP
+  // client instance. The idle timer should fire after SECONDS.
+  var client = new HttpClient();
+  client.idleTimeout = const Duration(seconds: SECONDS);
+
+  client.getUrl(uri)
+      .then((req) =>req.close())
+      .then((response) => response.drain())
+      .then((_) => print('drained client request'));
+}
+
+void main(List<String> args) {
+  if (args.length == 1) {
+    runClientProcess(args.first);
+  } else {
+    runServerProcess();
+  }
+}