Added the ability for testrunner to start the HTTP server with a random port and communicate that p…

utils/testrunner/run_pipeline.dart

Index: utils/testrunner/run_pipeline.dart
===================================================================
--- utils/testrunner/run_pipeline.dart	(revision 13499)
+++ utils/testrunner/run_pipeline.dart	(working copy)
@@ -6,6 +6,7 @@
 library pipeline;
 import 'dart:isolate';
 import 'dart:io';
+import 'dart:math';
 part 'pipeline_utils.dart';
 
 /**
@@ -37,14 +38,86 @@
 /** Process id for the HTTP server. */
 int serverId;
 
+/** Port used by HTTP server. */
+int serverPort;
+
+/** Root directory for static files used by HTTP server. */
+String serverRoot;
+
+/** Path of the HTTP server script. */
+String serverPath;
+
+/** Number of attempts we will make to start the HTTP server. */
+const int MAX_SERVER_TRIES = 10;
+
+/** Amount of time we give the server to start, in msec. */
+const int SERVER_DELAY = 1000;
+
 void main() {
   port.receive((cfg, replyPort) {
     config = cfg;
     initPipeline(replyPort);
-    wrapStage();
+    startHTTPServerStage();
   });
 }
 
+/** Initial pipeline stage - starts the HTTP server, if appropriate. */
+
+startHTTPServerStage() {
+  if (config["server"]) {
+    serverPath = config["testfile"];
+    // Replace .dart with _server.dart to get test's server file, if any.
+    var truncLen = serverPath.length - '.dart'.length;
+    serverPath = '${serverPath.substring(0, truncLen)}_server.dart';
+    var serverFile = new File(serverPath);
+    if (!serverFile.existsSync()) {
+      // No custom server; run the default server.
+      serverPath = '${config["runnerDir"]}/http_server_runner.dart';
+    }
+    if (serverPath != null) {
+      serverRoot = config["root"];
+      if (serverRoot == null) {
+        // Set the root to be the directory containing the test file.
+        serverRoot =  getDirectory(config["testfile"]);
+      }
+
+      if (config["port"] == null) {
+        // In this case we have to choose a random port and we need
+        // to see if the server starts successfully on that port.
+        var r = new Random();
+        tryStartHTTPServer(r, MAX_SERVER_TRIES);
+      } else {
+        serverPort = parseInt(config["port"]);
+        // Start the HTTP server.
+        serverId = startProcess(config["dart"],
+            [ serverPath, '--port=$serverPort', '--root=$serverRoot']);
+      }
+    }
+  }
+  wrapStage();
+}
+
+void tryStartHTTPServer(Random r, int remainingAttempts) {
+  // Pick a port from 1024 to 32767.
+  serverPort = 1024 + r.nextInt(32768-1024);

[Siggi Cherem (dart-lang), 2012/10/10 22:07:28]

nit: spaces around - 

[gram, 2012/10/10 23:36:04]

Done.

+  logMessage('Trying ${config["dart"]} $serverPath --port=$serverPort '
+      '--root=$serverRoot');
+  serverId = startProcess(config["dart"],
+      [ serverPath, '--port=$serverPort', '--root=$serverRoot']);
+  // Wait a second; if the process has exited try again with
+  // a different port, else go to next stage.
+  var t = new Timer(SERVER_DELAY, (t) {

[Siggi Cherem (dart-lang), 2012/10/10 22:07:28]

seems a bit brittle to wait 1 sec.

How about print something out from the subprocess so we can tell whether the
port was accepted? If the process exists before you get the print message, then
you try again?

[gram, 2012/10/10 23:36:04]

Done.

+    if (isProcessRunning(serverId)) {
+      wrapStage();
+    } else if (remainingAttempts == 0){

[Siggi Cherem (dart-lang), 2012/10/10 22:07:28]

nit: space before {

[gram, 2012/10/10 23:36:04]

Done.

[gram, 2012/10/10 23:36:04]

Done.

+      print('Failed to start HTTP server after numerous attempts; aborting.');
+      exit(1);
+    } else {
+      tryStartHTTPServer(r, remainingAttempts-1);

[Siggi Cherem (dart-lang), 2012/10/10 22:07:28]

nit: spaces

[gram, 2012/10/10 23:36:04]

Done.

[gram, 2012/10/10 23:36:04]

Done.

+    }
+  });
+}
+
 /** Initial pipeline stage - generates Dart and HTML wrapper files. */
 wrapStage() {
   var tmpDir = config["tempdir"];
@@ -102,6 +175,7 @@
       excludeFilters = ${config["exclude"]};
       tprint = (msg) => print('###\$msg');
       notifyDone = (e) {};
+      unittest.testState["port"] = $serverPort;
     ''';
   } else {
     directives = '''
@@ -116,6 +190,7 @@
       excludeFilters = ${config["exclude"]};
       tprint = (msg) => query('#console').addText('###\$msg\\n');
       notifyDone = (e) => window.postMessage('done', '*');
+      unittest.testState["port"] = $serverPort;
     ''';
   }
 
@@ -169,12 +244,12 @@
         main() {
           includeFilters = ${config["include"]};
           excludeFilters = ${config["exclude"]};
+          unittest.testState["port"] = $serverPort;
           runTests(test.main);
         }
     ''');
   }
 
-
   // Create the HTML wrapper and compile to Javascript if necessary.
   var isJavascript = config["runtime"] == 'drt-js';
   if (config["runtime"] == 'drt-dart' || isJavascript) {
@@ -251,28 +326,6 @@
 
 /** Third stage of pipeline - runs the tests. */
 runTestStage(_) {
-  if (config["server"]) {
-    var serverPath = config["testfile"];
-    // Replace .dart with _server.dart to get test's server file, if any.
-    var truncLen = serverPath.length - '.dart'.length;
-    serverPath = '${serverPath.substring(0, truncLen)}_server.dart';
-    var serverFile = new File(serverPath);
-    if (!serverFile.existsSync()) {
-      // No custom server; run the default server.
-      serverPath = '${config["runnerDir"]}/http_server_runner.dart';
-    }
-    if (serverPath != null) {
-      var root = config["root"];
-      if (root == null) {
-        // Set the root to be the directory containing the test file.
-        root =  getDirectory(config["testfile"]);
-      }
-      // Start the HTTP server.
-      serverId = startProcess(config["dart"],
-          [ serverPath, '--port=${config["port"]}', '--root=$root']);
-    }
-  }
-
   var cmd, args;
   if (config["runtime"] == 'vm' || config["layout"]) { // Run the tests.
     if (config["checked"]) {