Add find_timeouts and caching to tools/gardening

tools/gardening/bin/find_timeouts.dart

Index: tools/gardening/bin/find_timeouts.dart
diff --git a/tools/gardening/bin/find_timeouts.dart b/tools/gardening/bin/find_timeouts.dart
new file mode 100644
index 0000000000000000000000000000000000000000..e333955f75f1df6b6870312092b8bd372e6d0b11
--- /dev/null
+++ b/tools/gardening/bin/find_timeouts.dart
@@ -0,0 +1,139 @@
+// Copyright (c) 2017, 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.
+
+/// Scans past dart2js-windows test steps for timeouts and reports the
+/// frequency of each test that has timed out.
+
+import 'dart:async';
+import 'dart:io';
+import 'package:args/args.dart';
+import 'package:gardening/src/buildbot_data.dart';
+import 'package:gardening/src/buildbot_loading.dart';
+import 'package:gardening/src/buildbot_structures.dart';
+import 'package:gardening/src/logdog.dart' as logdog;
+import 'package:gardening/src/util.dart';
+
+main(List<String> args) async {
+  ArgParser argParser = createArgParser();
+  argParser.addFlag('logdog',
+      negatable: false, help: "Pull test results from logdog.");
+  argParser.addOption('start',
+      defaultsTo: '-2',
+      help: "Start pulling from the specified <build-number>.\n"
+          "Use negative numbers for the most recent builds;\n"
+          "for instance -2 for the second-to-last build.'");
+  ArgResults argResults = argParser.parse(args);
+  processArgResults(argResults);
+  List<String> arguments = argResults.rest;
+  if (arguments.length > 1) {
+    print('Usage: find_timeouts.dart [options] [<count>]');
+    print('Where <count> is the number of old builds that are scanned');
+    print('and options are:');
+    print(argParser.usage);
+    exit(1);
+  }
+  int buildNumberCount = 10;
+  if (arguments.length > 0) {
+    buildNumberCount = int.parse(arguments[0]);
+  }
+  int buildNumberOffset = int.parse(argResults['start']);
+
+  bool useLogDog = argResults['logdog'];
+
+  HttpClient client = new HttpClient();
+  BuildGroup group =
+      buildGroups.firstWhere((g) => g.groupName == 'dart2js-windows');
+  Map<String, List<Timeout>> timeouts = <String, List<Timeout>>{};
+  for (BuildSubgroup subgroup in group.subgroups) {
+    if (useLogDog) {
+      await readLogDogResults(subgroup, timeouts,
+          buildNumberOffset: buildNumberOffset,
+          buildNumberCount: buildNumberCount);
+    } else {
+      await readBuildBotResults(client, subgroup, timeouts,
+          buildNumberOffset: buildNumberOffset,
+          buildNumberCount: buildNumberCount);
+    }
+  }
+
+  List<String> sorted = timeouts.keys.toList()
+    ..sort((a, b) {
+      return -timeouts[a].length.compareTo(timeouts[b].length);
+    });
+
+  sorted.forEach((String testName) {
+    List<Timeout> list = timeouts[testName];
+    print('${padLeft('${list.length}', 4)} $testName');
+    for (Timeout timeout in list) {
+      print('     - ${timeout.buildUri.botName}/${timeout.buildUri.stepName} '
+          '${timeout.timeout.id} (${timeout.buildNumber})');
+    }
+  });
+
+  client.close();
+}
+
+Future readLogDogResults(
+    BuildSubgroup subgroup, Map<String, List<Timeout>> timeouts,
+    {int buildNumberOffset, int buildNumberCount}) async {
+  Map<String, String> subgroupPaths = subgroup.logDogPaths;
+  for (String shardName in subgroupPaths.keys) {
+    String subgroupPath = subgroupPaths[shardName];
+    List<int> buildNumbers = <int>[];
+    for (String line in logdog.ls(subgroupPath).split('\n')) {
+      line = line.trim();
+      if (line.isNotEmpty) {
+        buildNumbers.add(int.parse(line));
+      }
+    }
+    buildNumbers.sort((a, b) => -a.compareTo(b));
+    int buildNumberIndex;
+    if (buildNumberOffset < 0) {
+      buildNumberIndex = -buildNumberOffset - 1;
+    } else {
+      buildNumberIndex = buildNumbers.firstWhere((n) => n <= buildNumberOffset,
+          orElse: () => buildNumbers.length);
+    }
+    for (int i = 0; i < buildNumberCount; i++) {
+      if (buildNumberIndex + i < buildNumbers.length) {
+        int buildNumber = buildNumbers[buildNumberIndex + i];
+        for (BuildUri buildUri
+            in subgroup.createShardUris(shardName, buildNumber)) {
+          BuildResult result = await readLogDogResult(buildUri);
+          for (TestFailure timeout in result.timeouts) {
+            timeouts.putIfAbsent(timeout.id.testName, () => <Timeout>[]).add(
+                new Timeout(subgroup, result.buildNumber, buildUri, timeout));
+          }
+          buildUri = buildUri.prev();
+        }
+      }
+    }
+  }
+}
+
+Future readBuildBotResults(HttpClient client, BuildSubgroup subgroup,
+    Map<String, List<Timeout>> timeouts,
+    {int buildNumberOffset, int buildNumberCount}) async {
+  List<BuildUri> buildUris = subgroup.createUris(buildNumberOffset);
+  for (BuildUri buildUri in buildUris) {
+    for (int i = 0; i < buildNumberCount; i++) {
+      BuildResult result = await readBuildResult(client, buildUri);
+      for (TestFailure timeout in result.timeouts) {
+        timeouts
+            .putIfAbsent(timeout.id.testName, () => <Timeout>[])
+            .add(new Timeout(subgroup, result.buildNumber, buildUri, timeout));
+      }
+      buildUri = result.buildUri.prev();
+    }
+  }
+}
+
+class Timeout {
+  final BuildSubgroup subgroup;
+  final int buildNumber;
+  final BuildUri buildUri;
+  final TestFailure timeout;
+
+  Timeout(this.subgroup, this.buildNumber, this.buildUri, this.timeout);
+}