Added find-shard to bot.dart.

tools/gardening/bin/find_shard.dart

Index: tools/gardening/bin/find_shard.dart
diff --git a/tools/gardening/bin/find_shard.dart b/tools/gardening/bin/find_shard.dart
new file mode 100755
index 0000000000000000000000000000000000000000..90a223e34d27127536dfa64b56ebf801c4918de3
--- /dev/null
+++ b/tools/gardening/bin/find_shard.dart
@@ -0,0 +1,98 @@
+#!/usr/bin/env dart
+// 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.
+
+// Translates a buildbot shard name to the corresponding column group name
+// on the buildbot site, such that it's easier to find the right column.
+//
+// Example: `bin/find_shard.dart precomp-linux-debug-x64-be`
+// prints `vm-precomp(5): precomp-linux-debug-x64-be`.
+
+import 'dart:io';
+import 'package:args/args.dart';
+part 'package:gardening/src/shard_data.dart';
+
+ArgParser createArgParser() {
+  ArgParser argParser = new ArgParser(allowTrailingOptions: true);
+  argParser.addFlag('help', help: "Help");
+  return argParser;
+}
+
+bool INCLUDE_DEV =
+    const bool.fromEnvironment('INCLUDE_DEV', defaultValue: false);
+bool INCLUDE_STABLE =
+    const bool.fromEnvironment('INCLUDE_STABLE', defaultValue: false);
+bool INCLUDE_INTEGRATION =
+    const bool.fromEnvironment('INCLUDE_INTEGRATION', defaultValue: false);
+
+void processArgResults(ArgResults argResults) {
+  if (argResults['include-all']) {
+    INCLUDE_DEV = INCLUDE_STABLE = INCLUDE_INTEGRATION = true;
+  } else {
+    if (argResults['include-dev']) INCLUDE_DEV = true;
+    if (argResults['include-stable']) INCLUDE_STABLE = true;
+    if (argResults['include-integration']) INCLUDE_INTEGRATION = true;
+  }
+}
+
+void help(ArgParser argParser) {
+  print('Given a shard name or a substring thereof, search all buildbot');
+  print('shard names and print matching ones, along with their group.');
+  print('E.g., searching "drt" will show that there are several matching');
+  print('shards, all in the group "chrome", which may be helpful when');
+  print('navigating the buildbot web page based on blame email etc.\n');
+  print('Usage: find_shard [options] <shard>');
+  print('where options are:');
+  print(argParser.usage);
+}
+
+bool shard_enabled(String shard) {
+  if (shard.endsWith('-dev')) return INCLUDE_DEV;
+  if (shard.endsWith('-stable')) return INCLUDE_STABLE;
+  if (shard.endsWith('-integration')) return INCLUDE_INTEGRATION;
+  return true;
+}
+
+main(List<String> args) async {
+  ArgParser argParser = createArgParser();
+  argParser.addFlag("include-dev",
+      abbr: "d",
+      defaultsTo: false,
+      negatable: false,
+      help: "Include shards named *-dev");
+  argParser.addFlag("include-stable",
+      abbr: "s",
+      defaultsTo: false,
+      negatable: false,
+      help: "Include shards named *-stable");
+  argParser.addFlag("include-integration",
+      abbr: "i",
+      defaultsTo: false,
+      negatable: false,
+      help: "Include shards named *-integration");
+  argParser.addFlag("include-all",
+      abbr: "a",
+      defaultsTo: false,
+      negatable: false,
+      help: "Include all shards");
+  ArgResults argResults = argParser.parse(args);
+  processArgResults(argResults);
+
+  if (argResults.rest.length != 1 || argResults['help']) {
+    help(argParser);
+    if (argResults['help']) return;
+    exit(1);
+  }
+
+  String arg = argResults.rest.first;
+  for (String group in shardGroups.keys) {
+    List<String> shardGroup = shardGroups[group];
+    for (int i = 0; i < shardGroup.length; i++) {
+      String shard = shardGroup[i];
+      if (shard_enabled(shard) && shard.contains(arg)) {
+        print("$group(${i+1}): $shard");
+      }
+    }
+  }
+}