unplugged-system/external/rappor/bin/sum_bits.py

87 lines
2.3 KiB
Python
Executable File

#!/usr/bin/python
#
# Copyright 2014 Google Inc. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
Read the RAPPOR'd values on stdin, and sum the bits to produce a Counting Bloom
filter by cohort. This can then be analyzed by R.
"""
import csv
import sys
import rappor
def SumBits(params, stdin, stdout):
csv_in = csv.reader(stdin)
csv_out = csv.writer(stdout)
num_cohorts = params.num_cohorts
num_bloombits = params.num_bloombits
sums = [[0] * num_bloombits for _ in xrange(num_cohorts)]
num_reports = [0] * num_cohorts
for i, row in enumerate(csv_in):
try:
(user_id, cohort, unused_bloom, unused_prr, irr) = row
except ValueError:
raise RuntimeError('Error parsing row %r' % row)
if i == 0:
continue # skip header
cohort = int(cohort)
num_reports[cohort] += 1
if not len(irr) == params.num_bloombits:
raise RuntimeError(
"Expected %d bits, got %r" % (params.num_bloombits, len(irr)))
for i, c in enumerate(irr):
bit_num = num_bloombits - i - 1 # e.g. char 0 = bit 15, char 15 = bit 0
if c == '1':
sums[cohort][bit_num] += 1
else:
if c != '0':
raise RuntimeError('Invalid IRR -- digits should be 0 or 1')
for cohort in xrange(num_cohorts):
# First column is the total number of reports in the cohort.
row = [num_reports[cohort]] + sums[cohort]
csv_out.writerow(row)
def main(argv):
try:
filename = argv[1]
except IndexError:
raise RuntimeError('Usage: sum_bits.py <params file>')
with open(filename) as f:
try:
params = rappor.Params.from_csv(f)
except rappor.Error as e:
raise RuntimeError(e)
SumBits(params, sys.stdin, sys.stdout)
if __name__ == '__main__':
try:
main(sys.argv)
except RuntimeError, e:
print >>sys.stderr, e.args[0]
sys.exit(1)