Adding the initial code for Omnibot multi-machine support

testing/legion/common_lib.py

+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Common library methods used by both host and client controllers."""
+
+import argparse
+import logging
+import socket
+import sys
+import xmlrpclib
+
+LOGGING_FORMAT = ('%(asctime)s %(filename)s:%(lineno)s %(levelname)s] '

[M-A Ruel, 2015/02/03 01:48:41]

I'd probably wouldn't make it a named constant unless you plan to reuse it
elsewhere.

[Mike Meade, 2015/02/03 17:47:57]

Done.

+                  '%(message)s')
+LOGGING_DATE_FORMAT = '%H:%M:%S'
+LOGGING_LEVELS = ['DEBUG', 'INFO', 'WARNING', 'WARN', 'ERROR']
+MY_IP = socket.gethostbyname(socket.gethostname())
+SERVER_ADDRESS = ''
+SERVER_PORT = 31710
+DEFAULT_TIMEOUT_SECS = 20 * 60  # 30 minutes
+
+
+def InitLogging():
+  """Initialize the logging module.
+
+  Raises:
+    argparse.ArgumentError if the --verbosity arg is incorrect.
+  """
+  parser = argparse.ArgumentParser()
+  logging_action = parser.add_argument('--verbosity', default='ERROR')

[M-A Ruel, 2015/02/03 01:48:41]

I generally use instead action='count' then use it to index in:
levels = [logging.ERROR, logging.INFO, logging.DEBUG]
level = levels[min(options.verbosity, len(levels)-1)]

So that the caller can just do:
foo.py -vvv
and it's simpler :)

But I don't mind, just FYI.

[Mike Meade, 2015/02/03 17:47:57]

Acknowledged.

+  args, _ = parser.parse_known_args()
+  if args.verbosity not in LOGGING_LEVELS:
+    raise argparse.ArgumentError(
+        logging_action, 'Only levels %s supported' % str(LOGGING_LEVELS))
+  logging.basicConfig(format=LOGGING_FORMAT, datefmt=LOGGING_DATE_FORMAT,
+                      level=args.verbosity)
+
+
+def PrintCommandLine():

[M-A Ruel, 2015/02/03 01:48:41]

What's the use case? In particular I don't think the code inside is complex
enough to not warrant just copy-pasting it.

[Mike Meade, 2015/02/03 17:47:57]

Done.

+  """Print the command line used to run this program."""
+  print ' '.join(sys.argv)
+
+
+def ConnectToServer(server):
+  """Connect to an RPC server."""
+  addr = 'http://%s:%d' % (server, SERVER_PORT)
+  logging.debug('Connecting to RPC server at %s', addr)
+  return xmlrpclib.Server(addr)