Add common module for binary search tool

common module holds common logic between bisect and
binary_search_state for adding utils to PYTHONPATH
and for building the argument parser.

TEST=Run unit tests, run cros_pkg system test

Change-Id: I4085b28de011132c53b8fddf06e8745042ef8ea2
Reviewed-on: https://chrome-internal-review.googlesource.com/266996
Commit-Ready: Cassidy Burden <cburden@google.com>
Tested-by: Cassidy Burden <cburden@google.com>
Reviewed-by: Luis Lozano <llozano@chromium.org>

3 files changed, 230 insertions, 98 deletions

diff --git a/binary_search_tool/binary_search_state.py b/binary_search_tool/binary_search_state.py
index 997190d2..c584b5ef 100755
--- a/binary_search_tool/binary_search_state.py
+++ b/binary_search_tool/binary_search_state.py
@@ -10,15 +10,9 @@ import pickle
 import sys
 import tempfile
 
-# Programtically adding utils python path to PYTHONPATH
-if os.path.isabs(sys.argv[0]):
-  utils_pythonpath = os.path.abspath('{0}/..'.format(os.path.dirname(sys.argv[
-      0])))
-else:
-  wdir = os.getcwd()
-  utils_pythonpath = os.path.abspath('{0}/{1}/..'.format(wdir, os.path.dirname(
-      sys.argv[0])))
-sys.path.append(utils_pythonpath)
+# Adds utils to PYTHONPATH
+import common
+
 # Now we do import from utils
 from utils import command_executer
 from utils import logger
@@ -343,6 +337,7 @@ def _CanonicalizeScript(script_name):
   if not script_name.startswith('/'):
     return os.path.join('.', script_name)
 
+
 def Run(get_initial_items, switch_to_good, switch_to_bad, test_script,
         install_script=None, iterations=50, prune=True, noincremental=False,
         file_args=False, verify_level=1, prune_iterations=100, verbose=False,
@@ -387,86 +382,7 @@ def Main(argv):
   # Common initializations
 
   parser = argparse.ArgumentParser()
-  parser.add_argument('-n',
-                      '--iterations',
-                      dest='iterations',
-                      type=int,
-                      help='Number of iterations to try in the search.',
-                      default=50)
-  parser.add_argument('-i',
-                      '--get_initial_items',
-                      dest='get_initial_items',
-                      help=('Script to run to get the initial objects. '
-                            'If your script requires user input '
-                            'the --verbose option must be used'))
-  parser.add_argument('-g',
-                      '--switch_to_good',
-                      dest='switch_to_good',
-                      help=('Script to run to switch to good. '
-                            'If your switch script requires user input '
-                            'the --verbose option must be used'))
-  parser.add_argument('-b',
-                      '--switch_to_bad',
-                      dest='switch_to_bad',
-                      help=('Script to run to switch to bad. '
-                            'If your switch script requires user input '
-                            'the --verbose option must be used'))
-  parser.add_argument('-I',
-                      '--install_script',
-                      dest='install_script',
-                      default=None,
-                      help=('Optional script to perform building, flashing, '
-                            'and other setup before the test script runs.'))
-  parser.add_argument('-t',
-                      '--test_script',
-                      dest='test_script',
-                      help=('Script to run to test the '
-                            'output after packages are built.'))
-  parser.add_argument('-p',
-                      '--prune',
-                      dest='prune',
-                      action='store_true',
-                      default=False,
-                      help=('Script to run to test the output after '
-                            'packages are built.'))
-  parser.add_argument('-c',
-                      '--noincremental',
-                      dest='noincremental',
-                      action='store_true',
-                      default=False,
-                      help='Do not propagate good/bad changes incrementally.')
-  parser.add_argument('-f',
-                      '--file_args',
-                      dest='file_args',
-                      action='store_true',
-                      default=False,
-                      help='Use a file to pass arguments to scripts.')
-  parser.add_argument('-v',
-                      '--verify_level',
-                      dest='verify_level',
-                      type=int,
-                      default=1,
-                      help=('Check binary search assumptions N times '
-                            'before starting.'))
-  parser.add_argument('-N',
-                      '--prune_iterations',
-                      dest='prune_iterations',
-                      type=int,
-                      help='Number of prune iterations to try in the search.',
-                      default=100)
-  parser.add_argument('-V',
-                      '--verbose',
-                      dest='verbose',
-                      action='store_true',
-                      help='Print full output to console.')
-  parser.add_argument('-r',
-                      '--resume',
-                      dest='resume',
-                      action='store_true',
-                      help=('Resume bisection tool execution from state file.'
-                            'Useful if the last bisection was terminated '
-                            'before it could properly finish.'))
-
+  common.BuildArgParser(parser)
   logger.GetLogger().LogOutput(' '.join(argv))
   options = parser.parse_args(argv)
 
diff --git a/binary_search_tool/bisect.py b/binary_search_tool/bisect.py
index 007531c6..be6db75e 100755
--- a/binary_search_tool/bisect.py
+++ b/binary_search_tool/bisect.py
@@ -5,17 +5,9 @@ from __future__ import print_function
 
 import abc
 import argparse
-import os
 import sys
+import common
 
-if os.path.isabs(sys.argv[0]):
-  utils_pythonpath = os.path.abspath('{0}/..'.format(os.path.dirname(sys.argv[
-      0])))
-else:
-  wdir = os.getcwd()
-  utils_pythonpath = os.path.abspath('{0}/{1}/..'.format(wdir, os.path.dirname(
-      sys.argv[0])))
-sys.path.append(utils_pythonpath)
 from utils import command_executer
 from utils import logger
 
diff --git a/binary_search_tool/common.py b/binary_search_tool/common.py
new file mode 100644
index 00000000..c1e938fa
--- /dev/null
+++ b/binary_search_tool/common.py
@@ -0,0 +1,224 @@
+"""Common config and logic for binary search tool
+
+This module serves two main purposes:
+  1. Programatically include the utils module in PYTHONPATH
+  2. Create the argument parsing shared between binary_search_state.py and
+     bisect.py
+
+The argument parsing is handled by populating _ArgsDict with all arguments.
+_ArgsDict is required so that binary_search_state.py and bisect.py can share
+the argument parsing, but treat them slightly differently. For example,
+bisect.py requires that all argument defaults are suppressed so that overriding
+can occur properly (i.e. only options that are explicitly entered by the user
+end up in the resultant options dictionary).
+
+ArgumentDict inherits OrderedDict in order to preserve the order the args are
+created so the help text is made properly.
+"""
+
+from __future__ import print_function
+
+import argparse
+import collections
+import os
+import sys
+
+# Programatically adding utils python path to PYTHONPATH
+if os.path.isabs(sys.argv[0]):
+  utils_pythonpath = os.path.abspath('{0}/..'.format(
+      os.path.dirname(sys.argv[0])))
+else:
+  wdir = os.getcwd()
+  utils_pythonpath = os.path.abspath('{0}/{1}/..'.format(
+      wdir, os.path.dirname(sys.argv[0])))
+sys.path.append(utils_pythonpath)
+
+
+class ArgumentDict(collections.OrderedDict):
+  """Wrapper around OrderedDict, represents CLI arguments for program.
+
+  AddArgument enforces the following layout:
+  {
+      ['-n', '--iterations'] : {
+          'dest': 'iterations',
+          'type': int,
+          'help': 'Number of iterations to try in the search.',
+          'default': 50
+      }
+      [arg_name1, arg_name2, ...] : {
+          arg_option1 : arg_option_val1,
+          ...
+      },
+      ...
+  }
+  """
+  _POSSIBLE_OPTIONS = ['action', 'nargs', 'const', 'default', 'type', 'choices',
+                       'required', 'help', 'metavar', 'dest']
+
+  def AddArgument(self, *args, **kwargs):
+    """Add argument to ArgsDict, has same signature as argparse.add_argument
+
+    Emulates the the argparse.add_argument method so the internal OrderedDict
+    can be safely and easily populated. Each call to this method will have a 1-1
+    corresponding call to argparse.add_argument once BuildArgParser is called.
+
+    Args:
+      *args: The names for the argument (-V, --verbose, etc.)
+      **kwargs: The options for the argument, corresponds to the args of
+                argparse.add_argument
+
+    Returns:
+      None
+
+    Raises:
+      TypeError: if args is empty or if option in kwargs is not a valid
+                 option for argparse.add_argument.
+    """
+    if len(args) == 0:
+      raise TypeError('Argument needs at least one name')
+
+    for key in kwargs:
+      if key not in self._POSSIBLE_OPTIONS:
+        raise TypeError('Invalid option "%s" for argument %s' %
+                        (key, args[0]))
+
+    self[args] = kwargs
+
+
+_ArgsDict = ArgumentDict()
+
+
+def GetArgsDict():
+  """_ArgsDict singleton method"""
+  if not _ArgsDict:
+    _BuildArgsDict(_ArgsDict)
+  return _ArgsDict
+
+
+def BuildArgParser(parser, override=False):
+  """Add all arguments from singleton ArgsDict to parser.
+
+  Will take argparse parser and add all arguments in ArgsDict. Will ignore
+  the default and required options if override is set to True.
+
+  Args:
+    parser: type argparse.ArgumentParser, will call add_argument for every item
+            in _ArgsDict
+    override: True if being called from bisect.py. Used to say that default and
+              required options are to be ignored
+
+  Returns:
+    None
+  """
+  ArgsDict = GetArgsDict()
+
+  # Have no defaults when overriding
+  for arg_names, arg_options in ArgsDict.iteritems():
+    if override:
+      arg_options = arg_options.copy()
+      arg_options.pop('default', None)
+      arg_options.pop('required', None)
+
+    parser.add_argument(*arg_names, **arg_options)
+
+
+def _BuildArgsDict(args):
+  """Populate ArgumentDict with all arguments"""
+  args.AddArgument('-n',
+                   '--iterations',
+                   dest='iterations',
+                   type=int,
+                   help='Number of iterations to try in the search.',
+                   default=50)
+  args.AddArgument('-i',
+                   '--get_initial_items',
+                   dest='get_initial_items',
+                   help=('Script to run to get the initial objects. '
+                         'If your script requires user input '
+                         'the --verbose option must be used'))
+  args.AddArgument('-g',
+                   '--switch_to_good',
+                   dest='switch_to_good',
+                   help=('Script to run to switch to good. '
+                         'If your switch script requires user input '
+                         'the --verbose option must be used'))
+  args.AddArgument('-b',
+                   '--switch_to_bad',
+                   dest='switch_to_bad',
+                   help=('Script to run to switch to bad. '
+                         'If your switch script requires user input '
+                         'the --verbose option must be used'))
+  args.AddArgument('-I',
+                   '--install_script',
+                   dest='install_script',
+                   help=('Optional script to perform building, flashing, '
+                         'and other setup before the test script runs.'))
+  args.AddArgument('-t',
+                   '--test_script',
+                   dest='test_script',
+                   help=('Script to run to test the '
+                         'output after packages are built.'))
+  args.AddArgument('-p',
+                   '--prune',
+                   dest='prune',
+                   action='store_true',
+                   default=False,
+                   help=('Script to run to test the output after '
+                         'packages are built.'))
+  # --prune False override, opposite of --prune
+  args.AddArgument('--noprune',
+                   dest='prune',
+                   action='store_false',
+                   default=argparse.SUPPRESS)
+  args.AddArgument('-c',
+                   '--noincremental',
+                   dest='noincremental',
+                   action='store_true',
+                   default=False,
+                   help='Do not propagate good/bad changes incrementally.')
+  # --noincremental False override, opposite of --noincremental
+  args.AddArgument('--incremental',
+                   dest='noincremental',
+                   action='store_false',
+                   default=argparse.SUPPRESS)
+  args.AddArgument('-f',
+                   '--file_args',
+                   dest='file_args',
+                   action='store_true',
+                   default=False,
+                   help='Use a file to pass arguments to scripts.')
+  # --file_args False override, opposite of --file_args
+  args.AddArgument('--nofile_args',
+                   dest='file_args',
+                   action='store_false',
+                   default=argparse.SUPPRESS)
+  args.AddArgument('-v',
+                   '--verify_level',
+                   dest='verify_level',
+                   type=int,
+                   default=1,
+                   help=('Check binary search assumptions N times '
+                         'before starting.'))
+  args.AddArgument('-N',
+                   '--prune_iterations',
+                   dest='prune_iterations',
+                   type=int,
+                   help='Number of prune iterations to try in the search.',
+                   default=100)
+  args.AddArgument('-V',
+                   '--verbose',
+                   dest='verbose',
+                   action='store_true',
+                   help='Print full output to console.')
+  # --verbose False override, opposite of --verbose
+  args.AddArgument('--noverbose',
+                   dest='verbose',
+                   action='store_false',
+                   default=argparse.SUPPRESS)
+  args.AddArgument('-r',
+                   '--resume',
+                   dest='resume',
+                   action='store_true',
+                   help=('Resume bisection tool execution from state file.'
+                         'Useful if the last bisection was terminated '
+                         'before it could properly finish.'))