from boto.s3.connection import S3Connection from optparse import OptionParser from boto import UserAgent from . import common import traceback import itertools import random import string import struct import yaml import sys import re class DecisionGraphError(Exception): """ Raised when a node in a graph tries to set a header or key that was previously set by another node """ def __init__(self, value): self.value = value def __str__(self): return repr(self.value) class RecursionError(Exception): """Runaway recursion in string formatting""" def __init__(self, msg): self.msg = msg def __str__(self): return '{0.__doc__}: {0.msg!r}'.format(self) def assemble_decision(decision_graph, prng): """ Take in a graph describing the possible decision space and a random number generator and traverse the graph to build a decision """ return descend_graph(decision_graph, 'start', prng) def descend_graph(decision_graph, node_name, prng): """ Given a graph and a particular node in that graph, set the values in the node's "set" list, pick a choice from the "choice" list, and recurse. Finally, return dictionary of values """ node = decision_graph[node_name] try: choice = make_choice(node['choices'], prng) if choice == '': decision = {} else: decision = descend_graph(decision_graph, choice, prng) except IndexError: decision = {} for key, choices in node['set'].iteritems(): if key in decision: raise DecisionGraphError("Node %s tried to set '%s', but that key was already set by a lower node!" %(node_name, key)) decision[key] = make_choice(choices, prng) if 'headers' in node: decision.setdefault('headers', []) for desc in node['headers']: try: (repetition_range, header, value) = desc except ValueError: (header, value) = desc repetition_range = '1' try: size_min, size_max = repetition_range.split('-', 1) except ValueError: size_min = size_max = repetition_range size_min = int(size_min) size_max = int(size_max) num_reps = prng.randint(size_min, size_max) if header in [h for h, v in decision['headers']]: raise DecisionGraphError("Node %s tried to add header '%s', but that header already exists!" %(node_name, header)) for _ in xrange(num_reps): decision['headers'].append([header, value]) return decision def make_choice(choices, prng): """ Given a list of (possibly weighted) options or just a single option!, choose one of the options taking weights into account and return the choice """ if isinstance(choices, str): return choices weighted_choices = [] for option in choices: if option is None: weighted_choices.append('') continue try: (weight, value) = option.split(None, 1) except ValueError: weight = '1' value = option weight = int(weight) if value == 'null' or value == 'None': value = '' for _ in xrange(weight): weighted_choices.append(value) return prng.choice(weighted_choices) def expand_headers(decision): expanded_headers = [] for header in decision['headers']: h = expand(decision, header[0]) v = expand(decision, header[1]) expanded_headers.append([h, v]) return expanded_headers def expand(decision, value): c = itertools.count() fmt = RepeatExpandingFormatter() new = fmt.vformat(value, [], decision) return new class RepeatExpandingFormatter(string.Formatter): def __init__(self, _recursion=0): super(RepeatExpandingFormatter, self).__init__() # this class assumes it is always instantiated once per # formatting; use that to detect runaway recursion self._recursion = _recursion def get_value(self, key, args, kwargs): val = super(RepeatExpandingFormatter, self).get_value(key, args, kwargs) if self._recursion > 5: raise RecursionError(key) fmt = self.__class__(_recursion=self._recursion+1) # must use vformat not **kwargs so our SpecialVariables is not # downgraded to just a dict n = fmt.vformat(val, args, kwargs) return n class SpecialVariables(dict): charsets = { 'printable': string.printable, 'punctuation': string.punctuation, 'whitespace': string.whitespace, 'digits': string.digits } def __init__(self, orig_dict, prng): super(SpecialVariables, self).__init__(orig_dict) self.prng = prng def __getitem__(self, key): fields = key.split(None, 1) fn = getattr(self, 'special_{name}'.format(name=fields[0]), None) if fn is None: return super(SpecialVariables, self).__getitem__(key) if len(fields) == 1: fields.append('') return fn(fields[1]) def special_random(self, args): arg_list = args.split() try: size_min, size_max = arg_list[0].split('-', 1) except ValueError: size_min = size_max = arg_list[0] except IndexError: size_min = '0' size_max = '1000' size_min = int(size_min) size_max = int(size_max) length = self.prng.randint(size_min, size_max) try: charset_arg = arg_list[1] except IndexError: charset_arg = 'printable' if charset_arg == 'binary': num_bytes = length + 8 tmplist = [self.prng.getrandbits(64) for _ in xrange(num_bytes / 8)] tmpstring = struct.pack((num_bytes / 8) * 'Q', *tmplist) tmpstring = tmpstring[0:length] else: charset = self.charsets[charset_arg] tmpstring = ''.join([self.prng.choice(charset) for _ in xrange(length)]) # Won't scale nicely return tmpstring.replace('{', '{{').replace('}', '}}') def parse_options(): parser = OptionParser() parser.add_option('-O', '--outfile', help='write output to FILE. Defaults to STDOUT', metavar='FILE') parser.add_option('--seed', dest='seed', type='int', help='initial seed for the random number generator', metavar='SEED') parser.add_option('--seed-file', dest='seedfile', help='read seeds for specific requests from FILE', metavar='FILE') parser.add_option('-n', dest='num_requests', type='int', help='issue NUM requests before stopping', metavar='NUM') parser.add_option('--decision-graph', dest='graph_filename', help='file in which to find the request decision graph', metavar='NUM') parser.set_defaults(num_requests=5) parser.set_defaults(graph_filename='request_decision_graph.yml') return parser.parse_args() def randomlist(seed=None): """ Returns an infinite generator of random numbers """ rng = random.Random(seed) while True: yield rng.random() def _main(): """ The main script """ (options, args) = parse_options() random.seed(options.seed if options.seed else None) s3_connection = common.s3.main request_seeds = None if options.seedfile: FH = open(options.seedfile, 'r') request_seeds = FH.readlines() else: random_list = randomlist(options.seed) request_seeds = itertools.islice(random_list, options.num_requests) graph_file = open(options.graph_filename, 'r') decision_graph = yaml.safe_load(graph_file) constants = { 'bucket_readable': 'TODO', 'bucket_not_readable': 'TODO', 'bucket_writable' : 'TODO', 'bucket_not_writable' : 'TODO', 'object_readable' : 'TODO', 'object_not_readable' : 'TODO', 'object_writable' : 'TODO', 'object_not_writable' : 'TODO', } for request_seed in request_seeds: prng = random.Random(request_seed) decision = assemble_decision(decision_graph, prng) decision.update(constants) request = expand_decision(decision, prng) response = s3_connection.make_request(request['method'], request['path'], data=request['body'], headers=request['headers'], override_num_retries=0) if response.status == 500 or response.status == 503: print 'Request generated with seed %d failed:\n%s' % (request_seed, request) pass def main(): common.setup() try: _main() except Exception as e: traceback.print_exc() common.teardown()