# Copyright (c) 2012-2016 Hewlett Packard Enterprise Development LP
#
# Permission to use, copy, modify, and/or distribute this software for
# any purpose with or without fee is hereby granted, provided that the
# above copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
# WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
# MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
# ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
# WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
# ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
# OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
from __future__ import absolute_import, print_function
import argparse
import bdb
import logging
import os.path
import re
import signal
import sys
import textwrap
import traceback
import warnings
try:
import epdb
except ImportError:
import pdb
import six
from requestbuilder import Arg, MutuallyExclusiveArgList
from requestbuilder.config import ConfigData, ConfigView
from requestbuilder.exceptions import ArgumentError
from requestbuilder.logging import configure_root_logger
from requestbuilder.suite import RequestBuilder
from requestbuilder.util import add_default_routes, aggregate_subclass_fields
class BaseCommand(object):
"""
The basis for a command line tool. To invoke this as a command line tool,
call the run() method on the class. Arguments will be parsed from the
command line. To invoke this in another context, such as from inside
another command, pass keyword arguments to __init__() with names that match
those stored by the argument parser and then call main() to retrieve a
result.
The general workflow of a command involves two methods: main(), which
inspects the arguments stored in self.args, does something, and returns a
result; and print_result(), which takes the output of main() and prints it
to stdout. By default, both of these methods do nothing. It is up to you
to implement them to do what the tool is designed to do.
Important members of this class include:
- DESCRIPTION: a string that describes the tool, which is re-wrapped and
used as part of the command line help string. If it is
not supplied, the class's doc string, if any, will be
used instead.
- USAGE: a usage message for the command line help string. If this
is None, one will be generated automatically.
- ARGS: a list of Arg and/or MutuallyExclusiveArgGroup objects
are used to generate command line arguments. Inheriting
classes needing to add command line arguments should
contain their own ARGS lists, which are combined with
those of their parent classes.
"""
DESCRIPTION = ''
USAGE = None
ARGS = []
DEFAULT_ROUTES = ()
SUITE = RequestBuilder
__CONFIGURED_GLOBAL_STATE = False
def __init__(self, config=None, loglevel=None, _do_cli=False, **kwargs):
self.args = kwargs
self.config = config # created by _process_configfiles if None
self.log = None # created by _configure_logging
self.suite = self.SUITE()
self._arg_routes = {} # arg name -> tuple of callables or dicts
self._cli_parser = None # created by _build_parser
self.__debug = False
self.__do_cli = _do_cli
self._configure_logging(loglevel)
self._process_configfiles()
if self.__do_cli and not BaseCommand.__CONFIGURED_GLOBAL_STATE:
self._configure_global_logging()
BaseCommand.__CONFIGURED_GLOBAL_STATE = True
# We need to enforce arg constraints in one location to make this
# framework equally useful for chained commands and those driven
# directly from the command line. Thus, we do most of the parsing/
# validation work before __init__ returns as opposed to putting it
# off until we hit CLI-specific code.
#
# Derived classes MUST call this method to ensure things stay sane.
self._build_parser()
if self.__do_cli:
# Distribute CLI args to the various places that need them
self.process_cli_args()
# This will raise an exception if kwargs contains anything unexpected.
self.distribute_args()
try:
self.configure()
except ArgumentError as err:
if self.__do_cli and not self.__debug:
# This is the only context in which we have a parser object,
# so if we don't handle this here and now the caller will have
# to handle it without one, which means no usage info for the
# user.
#
# This is contingent on self.__debug and not self.debug because
# run(), having no idea whether the config enables debugging or
# not, is going to terminate the program anyway regardless of
# that.
self._cli_parser.error(str(err))
else:
raise
@classmethod
def from_other(cls, other, **kwargs):
kwargs.setdefault('loglevel', other.log.level)
new = cls(config=other.config, **kwargs)
# That already calls configure
return new
def _configure_logging(self, loglevel):
self.log = logging.getLogger(self.name)
if loglevel is not None:
self.log.setLevel(loglevel)
elif self.debug:
self.log.setLevel(logging.DEBUG)
def _process_configfiles(self):
if self.config is None:
config_files = self.suite.list_config_files()
config_data = ConfigData(config_files)
self.config = ConfigView(config_data)
# Now that we have a config file we should check to see if it wants
# us to turn on debugging
if self.debug:
self.log.setLevel(logging.DEBUG)
self.config.log.setLevel(logging.DEBUG)
def _configure_global_logging(self):
if self.config.get_global_option('debug') in ('color', 'colour'):
configure_root_logger(use_color=True)
else:
configure_root_logger()
def _build_parser(self):
description = _rewrap_description(
self.DESCRIPTION or self.__doc__ or '')
parser = argparse.ArgumentParser(
description=description, usage=self.USAGE, add_help=False,
formatter_class=argparse.RawDescriptionHelpFormatter)
arg_objs = self.collect_arg_objs()
self._populate_parser(parser, arg_objs)
# Low-level basic args that affect the core of the framework
# These don't actually show up once CLI args finish processing.
parser.add_argument('--debug', action='store_true', dest='_debug',
default=argparse.SUPPRESS,
help='show debugging output')
parser.add_argument('--debugger', action='store_true',
dest='_debugger', default=argparse.SUPPRESS,
help='launch interactive debugger on error')
parser.add_argument('--version', action='version',
version=self.suite.format_version(),
help="show the program's version and exit")
if any('-h' in arg_obj.pargs for arg_obj in arg_objs
if isinstance(arg_obj, Arg)):
parser.add_argument('--help', action='help',
default=argparse.SUPPRESS,
help='show this help message and exit')
else:
parser.add_argument('-h', '--help', action='help',
default=argparse.SUPPRESS,
help='show this help message and exit')
self._cli_parser = parser
def collect_arg_objs(self):
arg_objs = aggregate_subclass_fields(self.__class__, 'ARGS')
add_default_routes(arg_objs, self.DEFAULT_ROUTES)
return arg_objs
def _populate_parser(self, parser, arg_objs):
for arg_obj in arg_objs:
self.__add_arg_to_cli_parser(arg_obj, parser)
def __add_arg_to_cli_parser(self, arglike_obj, parser):
# Returns the args the parser was populated with
if isinstance(arglike_obj, Arg):
if arglike_obj.kwargs.get('dest') is argparse.SUPPRESS:
# Treat it like it doesn't exist at all
return []
else:
arg = parser.add_argument(*arglike_obj.pargs,
**arglike_obj.kwargs)
if arglike_obj.routes is None:
self._arg_routes[arg.dest] = (None,)
else:
self._arg_routes[arg.dest] = arglike_obj.routes
return [arg]
elif isinstance(arglike_obj, MutuallyExclusiveArgList):
exgroup = parser.add_mutually_exclusive_group(
required=arglike_obj.is_required)
args = []
for group_arg in arglike_obj:
args.extend(self.__add_arg_to_cli_parser(group_arg, exgroup))
return args
elif isinstance(arglike_obj, list) or isinstance(arglike_obj, tuple):
args = []
for group_arg in arglike_obj:
args.extend(self.__add_arg_to_cli_parser(group_arg, parser))
return args
else:
raise TypeError('Unknown argument type ' +
arglike_obj.__class__.__name__)
def process_cli_args(self):
cli_args = vars(self._cli_parser.parse_args())
if cli_args.pop('_debug', False):
self.__debug = True
if cli_args.pop('_debugger', False):
self.__debug = True
sys.excepthook = _debugger_except_hook
signal.signal(signal.SIGUSR1, _debugger_usr1_handler)
# Everything goes in self.args. distribute_args() also puts them
# elsewhere later on in the process.
self.args.update(cli_args)
redacted = type('REDACTED', (),
{'__repr__': lambda self: '<redacted>'})()
for key in list(cli_args.keys()):
if (('password' in key.lower() or 'secret' in key.lower()) and
cli_args[key] is not None):
# This makes it slightly more obvious that this is redacted by
# the framework and not just a string by removing quotes.
cli_args[key] = redacted
self.log.debug('parsed arguments from CLI: %s', str(cli_args))
def distribute_args(self):
for key, val in six.iteritems(self.args):
# If a location to route this to was supplied, put it there, too.
if key not in self._arg_routes:
raise TypeError('got unrecognized arg: "{0}"'.format(key))
routes = self._arg_routes[key]
for route in routes:
if route is not None:
if callable(route):
# If it's callable, call it to get the actual
# destination dict. This is needed to allow Arg
# objects to refer to instance attributes from the
# context of the class.
route = route(self)
# At this point we had better have a dict.
route[key] = val
def configure(self):
# TODO: rename this to setup
pass
@classmethod
def run(cls):
try:
cmd = cls(_do_cli=True)
except Exception as err:
msg_prefix = '{0}: error:'.format(os.path.basename(sys.argv[0]))
if isinstance(err, EnvironmentError):
# These don't have regular 'args' attributes, and they occur
# frequently enough they we handle them specially.
err_bits = [msg_prefix]
if getattr(err, 'strerror', None):
err_bits.append(err.strerror)
if getattr(err, 'filename', None):
err_bits[-1] += ':'
err_bits.append(err.filename)
print(' '.join(err_bits), file=sys.stderr)
else:
if len(err.args) > 0 and err.args[0]:
print(msg_prefix, err.args[0], file=sys.stderr)
else:
print(msg_prefix, str(err), file=sys.stderr)
# Since we don't even have a config file to consult our options for
# determining when debugging is on are limited to what we got at
# the command line.
if any(arg in sys.argv for arg in ('--debug', '--debugger')):
raise
sys.exit(1)
try:
result = cmd.main()
cmd.print_result(result)
except Exception as err:
cmd.handle_cli_exception(err)
@property
def name(self):
return self.__class__.__name__
def main(self):
'''
The main processing method. main() is expected to do something with
self.args and return a result.
'''
pass
def print_result(self, data):
'''
Take a result produced by main() and print it to stdout.
'''
pass
@property
def debug(self):
if self.__config_enables_debugging():
return True
if self.__debug:
return True
if any(arg in sys.argv for arg in ('--debug', '--debugger')):
# In case an error occurs during argument parsing
return True
return False
def handle_cli_exception(self, err):
msg_prefix = '{0}: error:'.format(os.path.basename(sys.argv[0]))
if isinstance(err, ArgumentError) and self.__do_cli and not self.debug:
# Note that, unlike __init__, we get to use self.debug instead
# of self.__debug
self._cli_parser.error(str(err))
if isinstance(err, EnvironmentError):
# These don't have regular 'args' attributes, and they occur
# frequently enough they we handle them specially.
err_bits = [msg_prefix]
if getattr(err, 'strerror', None):
err_bits.append(err.strerror)
if getattr(err, 'filename', None):
err_bits[-1] += ':'
err_bits.append(err.filename)
print(' '.join(err_bits), file=sys.stderr)
else:
if len(err.args) > 0 and err.args[0]:
print(msg_prefix, err.args[0], file=sys.stderr)
else:
print(msg_prefix, str(err), file=sys.stderr)
if self.debug:
raise
sys.exit(1)
def __config_enables_debugging(self):
if self.config is None:
return False
if self.config.get_global_option('debug') in ('color', 'colour'):
return True
if self.config.convert_to_bool(self.config.get_global_option('debug')):
return True
return False
def _debugger_except_hook(type_, value, tracebk):
'''
Launch epdb (or pdb if epdb is unavailable) when an uncaught exception
occurs.
'''
if type_ is bdb.BdbQuit:
sys.exit(1)
sys.excepthook = sys.__excepthook__
if sys.stdout.isatty() and sys.stdin.isatty():
if 'epdb' in sys.modules:
epdb.post_mortem(tracebk, type_, value)
else:
pdb.post_mortem(tracebk)
else:
traceback.print_tb(tracebk)
sys.exit(1)
def _debugger_usr1_handler(_, frame):
"""
Show a traceback and local variables when sent SIGUSR1. Note that
this could cause exceptions due to interrupted system calls.
"""
frame_dict = {'_frame': frame}
frame_dict.update(frame.f_globals)
frame_dict.update(frame.f_locals)
print(''.join(traceback.format_stack(frame)), file=sys.stderr)
def _rewrap_description(text, width=70):
"""
Split lines into paragraphs based on blank lines and changes in
indentation level, rewrap the text in each of those paragraphs, and
yield each of those paragraphs. In paragraphs that start with
common shell prompt characters (#, $, and %) or bullets (* and -)
followed by whitespace, those characters do not count against the
paragraph's indentation level.
"""
# Match shell prompts and bullets
bullets = {r'^(\s*)\#(\s+)': r'\1 \2',
r'^(\s*)\$(\s+)': r'\1 \2',
r'^(\s*)\%(\s+)': r'\1 \2',
r'^(\s*)\*(\s+)': r'\1 \2',
r'^(\s*)\-(\s+)': r'\1 \2'}
def measure_margin(line):
if not line.strip():
return -1
for pattern, sub in bullets.iteritems():
line = re.sub(pattern, sub, line)
return len(line) - len(line.lstrip())
def find_bullet_pattern(line):
for pattern in bullets:
if line and re.match(pattern, line):
return pattern
def reformat_paragraph(lines, width=70):
if not lines:
return ''
margin = measure_margin(lines[0])
pattern = find_bullet_pattern(lines[0])
if pattern:
firstline_margin = len(lines[0]) - len(lines[0].lstrip())
bullet_text = lines[0][firstline_margin:margin]
lines[0] = re.sub(pattern, bullets[pattern], lines[0], 1)
rewrapped = textwrap.wrap('\n'.join(line.strip() for line in lines),
width=(width - margin))
if pattern:
combined = ([' ' * firstline_margin + bullet_text + rewrapped[0]] +
[' ' * margin + line for line in rewrapped[1:]])
else:
combined = [' ' * margin + line for line in rewrapped]
combined = '\n'.join(' ' * margin + line for line in rewrapped)
if pattern:
combined = ' ' * firstline_margin + bullet_text + combined[margin:]
return combined
text %= dict(prog=os.path.basename(sys.argv[0]))
in_lines = textwrap.dedent(text.rstrip().lstrip('\n')).splitlines()
paragraphs = []
current_lines = []
current_margin = 0
for line in in_lines:
if not line.strip():
paragraphs.append(reformat_paragraph(current_lines,
width=width))
del current_lines[:]
current_lines.append('')
current_margin = -1
else:
pattern = find_bullet_pattern(line)
margin = measure_margin(line)
if pattern:
# Bullets always begin new paragraphs
paragraphs.append(reformat_paragraph(current_lines,
width=width))
del current_lines[:]
elif margin != current_margin:
# Different margin -> start new paragraph
paragraphs.append(reformat_paragraph(current_lines,
width=width))
del current_lines[:]
current_margin = margin
current_lines.append(line)
if current_lines:
paragraphs.append(reformat_paragraph(current_lines, width=width))
# Combine adjacent empty paragraphs
for i in xrange(len(paragraphs) - 1, 0, -1):
if paragraphs[i] == paragraphs[i - 1] == '':
del paragraphs[i]
return '\n'.join(paragraphs)