sstable-compressioninfo.py

#!/usr/bin/env python3

import argparse
import binascii
import struct
import sstable_tools.sstablelib as sstablelib
import itertools
import operator
import statistics
import textwrap

cmdline_parser = argparse.ArgumentParser()
cmdline_parser.add_argument('compressioninfo_file', nargs='+', help='CompressionInfo file(s) to parse')
cmdline_parser.add_argument('--summary', action='store_true', help='generate a summary instead of full output')

args = cmdline_parser.parse_args()

for fname in args.compressioninfo_file:
    s = sstablelib.Stream(open(fname, 'rb').read())
    algo = s.string16()
    options = s.map32()
    chunk_size = s.int32()
    data_len = s.int64()
    offsets = s.array32(sstablelib.Stream.int64)
    end = offsets[1:] + [offsets[-1]]
    diffs = list(itertools.starmap(operator.__sub__, zip(end, offsets)))
    avg_chunk = int(statistics.mean(diffs[:-1]))
    min_chunk = min(diffs[:-1])
    max_chunk = max(diffs[:-1])
    nr_chunks = len(offsets)

    if args.summary:
        print('{data_len:12} {chunk_size:6} {min_chunk:6} {avg_chunk:6} {max_chunk:6} {fname}'.format(**locals()))
    else:
        print(textwrap.dedent('''
            File: {fname}
            Algorithm: {algo}
            Options: {options}
            Chunk size: {chunk_size}
            Data length: {data_len}
            Number of chunks: {nr_chunks}
            Offsets:'''
            ).format(**locals()))
        for offset in offsets:
            print('    {offset}'.format(**locals()))
        print()