dmefilter

#! /usr/bin/env python

#
# Copyright (c) 2015 Google Inc.
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## Tool to split the combined debug and DME logging streams into to outputs
#

from __future__ import print_function
import os
import sys
import argparse

# Program return values
PROGRAM_SUCCESS = 0
PROGRAM_WARNINGS = 1
PROGRAM_ERRORS = 2


def load_file(filename):
    """ Load a file into a list

    If a filename is specified, it will load it from that file.
    If no filename is specified, it will load it from stdin.

    Returns a list of the lines in the file
    """
    if filename:
        with open(filename, "r") as f:
            return f.readlines()
    else:
        return sys.stdin.readlines()


def split_log(logfile, write_to_files):
    """ Split the log into 2 separate streams

    Takes a logfile (via the --log parameter), or uses stdin if no logfile
    specified, and splits it into a debug and dme streams.

    If write_to_files is specified, then it will write the dme stream to
    <logfile>-dme.rsp and the debug stream to <logfile>.rsp.  If logfile
    wasn't specified, it uses "log" as the base name. If write_to_files is
    not specified, then the debug stream goes out on stdout and the dme
    stream goes out on stderr.

    Thus, one can use it as a filter or as a file processor.
    """
    # Read the log file/stream into a list
    log = load_file(logfile)

    if write_to_files:
        # Filter the list to <log>.rsp (dbg) and <log>-dme.rsp (dme)
        # It will use "log" for <log> if there is no input file.
        if not logfile:
            logfile = "log"

        root, ext = os.path.splitext(logfile)
        dme_file = root + "-dme.rsp"
        dbg_file = root + ".rsp"
        with open(dbg_file, "w") as dbg:
            with open(dme_file, "w") as dme:
                for log_line in log:
                    log_line = log_line.rstrip()
                    if log_line[0:3].lower() == "id=":
                        print(log_line, file=dme)
                    else:
                        print(log_line, file=dbg)
    else:
        # Filter the list to stdout (dbg) and stderr (dme)
        for log_line in log:
            log_line = log_line.rstrip()
            if log_line[0:3].lower() == "id=":
                print(log_line, file=sys.stderr)
            else:
                print(log_line)


def main():
    """ Tool to split the combined debug and DME logging streams

    Usage:
      - As a filter:
            dmefilter < capture.txt > foo 2> bar
            <debug_capture> | dmefilter > foo 2> bar
        Process the input on stdin, with debug output going to stdout and
        DME output going to stderr.
      - As a file processor:
            dmefilter --log capture.txt -out
        Process the log file, with debug output written to <log>.rsp and
        DME output written to <log>-dme.rsp

    The input selection (file/stdin) is independant of the --out option. If
    --out is specified with stdin, then the generated files are log.rsp and
    log-dme.rsp.
    """
    parser = argparse.ArgumentParser()

    # Capture-specific args:
    parser.add_argument("--log",
                        help="The name of the log file")

    parser.add_argument("--out",
                        action='store_true',
                        help="Store the results in <log>-dbg.rsp and "
                             "<log>-dme.rsp")

    args = parser.parse_args()
    split_log(args.log, args.out)
    sys.exit(PROGRAM_SUCCESS)


## Launch main
#
if __name__ == '__main__':
    main()