#!/usr/bin/env python3
# This file is part of GNU TALER.
# Copyright (C) 2018 INRIA
#
# TALER is free software; you can redistribute it and/or modify it under the
# terms of the GNU Lesser General Public License as published by the Free Software
# Foundation; either version 2.1, or (at your option) any later version.
#
# TALER is distributed in the hope that it will be useful, but WITHOUT ANY
# WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
# A PARTICULAR PURPOSE.  See the GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License along with
# GNU TALER; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
#
# @author Florian Dold

"""
Wrapper for programs that log to stderr.  Redirects logs to a file specified by
a path with strfmt-style placeholders in it.
"""

from subprocess import Popen, PIPE
import sys
import os
import os.path
import signal
import time

def handler(signum, frame):
    if p:
        os.kill(p.pid, signum)
    else:
        sys.exit(-1)

def touchp(path):
    dir = os.path.dirname(path)
    if dir:
        os.makedirs(dir, exist_ok=True)

if len(sys.argv) < 3:
    print("Usage: {} logfile prog_and_args...".format(sys.argv[0]), file=sys.stderr)
    sys.exit(-1)

p = None
catchable_sigs = set(signal.Signals) - {signal.SIGKILL, signal.SIGSTOP}
for sig in catchable_sigs:
    signal.signal(sig, handler)
p = Popen(sys.argv[2:], stderr=PIPE, shell=False)

log = sys.argv[1]
last_name = None

while p.poll() is None:
    full_name = time.strftime(log)
    if full_name != last_name:
        touchp(full_name)
        last_name = full_name
    last_read = p.stderr.readline()
    if last_read == '':
        break
    with open(full_name, "ab") as f:
        f.write(last_read)

status = p.wait()
sys.exit(status)