Add a tool for viewing instrumentation logs

pkg/analysis_server/tool/instrumentation/log_viewer.dart

Index: pkg/analysis_server/tool/instrumentation/log_viewer.dart
diff --git a/pkg/analysis_server/tool/instrumentation/log_viewer.dart b/pkg/analysis_server/tool/instrumentation/log_viewer.dart
new file mode 100644
index 0000000000000000000000000000000000000000..d18cdf76609e72a3e50a79de745abaac36f19e57
--- /dev/null
+++ b/pkg/analysis_server/tool/instrumentation/log_viewer.dart
@@ -0,0 +1,128 @@
+// Copyright (c) 2016, 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' as io;
+
+import 'package:args/args.dart';
+
+import 'log.dart';
+import 'server.dart';
+
+/**
+ * Start a web server that will allow an instrumentation log to be viewed.
+ */
+void main(List<String> args) {
+  Driver driver = new Driver();
+  driver.start(args);
+}
+
+/**
+ * The main driver that configures and starts the web server.
+ */
+class Driver {
+  /**
+   * The flag used to specify that the user wants to have help text printed but
+   * that no other work should be done.
+   */
+  static String helpFlag = 'help';
+
+  /**
+   * The option used to specify the port on which the server should listen for
+   * requests.
+   */
+  static String portOption = 'port';
+
+  /**
+   * The port that will be used if no port number is provided on the command
+   * line.
+   */
+  static int defaultPortNumber = 11000;
+
+  /**
+   * Initialize a newly created driver.
+   */
+  Driver();
+
+  /**
+   * Create and return the parser used to parse the command-line arguments.
+   */
+  ArgParser createParser() {
+    ArgParser parser = new ArgParser();
+    parser.addFlag(helpFlag, help: 'Print this help text', negatable: false);
+    parser.addOption(portOption,
+        help: 'The port number on which the server should listen for requests',
+        defaultsTo: defaultPortNumber.toString());
+    return parser;
+  }
+
+  /**
+   * Print usage information.
+   */
+  void printUsage(ArgParser parser,
+      {String error, Object exception, StackTrace stackTrace}) {
+    if (error != null) {
+      print(error);
+      print('');
+    }
+    print('log_viewer [options] logFile');
+    print('');
+    print('Usage:');
+    print('');
+    print(
+        'The "logFile" is the file containing the content of the log that is being viewed');
+    print('');
+    print('Options:');
+    print(parser.usage);
+    if (exception != null) {
+      print(exception);
+    }
+    if (stackTrace != null) {
+      print(stackTrace);
+    }
+  }
+
+  /**
+   * Use the given command-line [args] to configure and start the web server.
+   */
+  void start(List<String> args) {
+    ArgParser parser = createParser();
+    ArgResults options = parser.parse(args);
+    if (options[helpFlag]) {
+      printUsage(parser);
+      return;
+    }
+
+    int port = defaultPortNumber;
+    try {
+      port = int.parse(options[portOption]);
+    } catch (exception) {
+      printUsage(parser, error: 'Invalid port number');
+      return;
+    }
+
+    List<String> arguments = options.rest;
+    if (arguments == null || arguments.length != 1) {
+      printUsage(parser, error: 'Missing log file');
+      return;
+    }
+    String fileName = arguments[0];
+    io.File logFile = new io.File(fileName);
+    List<String> lines;
+    try {
+      lines = logFile.readAsLinesSync();
+    } catch (exception, stackTrace) {
+      printUsage(parser,
+          error: 'Could not read file "$fileName":',
+          exception: exception,
+          stackTrace: stackTrace);
+      return;
+    }
+
+    InstrumentationLog log =
+        new InstrumentationLog(<String>[logFile.path], lines);
+    WebServer server = new WebServer(log);
+    server.serveHttp(port);
+    print('logViewer is listening on http://localhost:$port/log');
+  }
+}