#!/usr/bin/env python3
# coding: utf-8

# Copyright (C) 1994-2021 Altair Engineering, Inc.
# For more information, contact Altair at www.altair.com.
#
# This file is part of both the OpenPBS software ("OpenPBS")
# and the PBS Professional ("PBS Pro") software.
#
# Open Source License Information:
#
# OpenPBS is free software. You can redistribute it and/or modify it under
# the terms of the GNU Affero General Public License as published by the
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# option) any later version.
#
# OpenPBS 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 Affero General Public
# License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Commercial License Information:
#
# PBS Pro is commercially licensed software that shares a common core with
# the OpenPBS software.  For a copy of the commercial license terms and
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# organizations to create proprietary derivative works of OpenPBS and
# distribute them - whether embedded or bundled with other software -
# under a commercial license agreement.
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# Use of Altair's trademarks, including but not limited to "PBS™",
# "OpenPBS®", "PBS Professional®", and "PBS Pro™" and Altair's logos is
# subject to Altair's trademark licensing policies.


import sys
import os
import getopt
import logging
import tempfile
import errno

import ptl
try:
    from ptl.lib.pbs_ifl import pbs_py_spawn
    from ptl.lib.pbs_testlib import Server, MoM, JOB, ResourceResv
    from ptl.utils.pbs_cliutils import CliUtils
except Exception:
    sys.stderr.write("API wrapping is required, see pbs_swigify utility")
    exit(1)


# trap SIGINT and SIGPIPE
def trap_exceptions(etype, value, tb):
    sys.excepthook = sys.__excepthook__
    if issubclass(etype, KeyboardInterrupt):
        pass
    elif issubclass(etype, IOError) and value.errno == errno.EPIPE:
        pass
    else:
        sys.__excepthook__(etype, value, tb)


sys.excepthook = trap_exceptions

# Helper script to allow a py_spawned script to run detached from the
# session associated to a PBS Job

# sys.argv[1] must be a valid path to the pbs_attach command
# sys.argv[2] must be a valid job identifier
# sys.argv[3:] must be a valid path to a Python script and args to run in
# the background. The first output of this script must be its PID (e.g., a
# shell script shall echo $$)
_wrapper_body = """import os
import sys
from subprocess import Popen, PIPE

if len(sys.argv) < 3:
    exit(1)

(r, w) = os.pipe()
p = os.fork()
if p < 0:
    exit(1)
elif p > 0:
    os.close(w)
    pid = os.read(r, 256)
    p = Popen([sys.argv[1], "-j", sys.argv[2], "-p", str(pid)], stdout=PIPE)
    p.communicate()
    os.close(r)
    exit(p.retcode)
# child
os.close(r)
p = Popen(["setsid"] + sys.argv[3:], stdout=PIPE)
os.write(w, p.stdout.readline())
os.close(w)
"""


def usage():
    msg = []
    msg += ['Usage: ' + os.path.basename(sys.argv[0]) + ' [OPTION] '
            '<path> <args>\n\n']
    msg += ['   Run a py_spawn command\n\n']
    msg += ['-e <envs>: comma-separated list of environment options\n']
    msg += ['-j <jobid>: jobid to which the spawned process is run\n']
    msg += ['-l <level>: logging level, INFO, DEBUG, ..., defaults to ERROR\n']
    msg += ['-t <hostname>: target hostname to operate on\n']
    msg += ['--detach: If set, run Python script in background\n']
    msg += ['--wrapper=<path>: Optional path to wrapper script, to use with '
            'detach\n']
    msg += ['--version: print version number and exit\n']

    print("".join(msg))


if __name__ == '__main__':

    if len(sys.argv) < 2:
        usage()
        sys.exit(0)

    jobid = None
    envs = []
    detach = False
    lvl = logging.ERROR
    wrapper = None
    cleanup_wrapper = False
    hostname = None

    try:
        opts, args = getopt.getopt(sys.argv[1:], "e:j:l:t:hw",
                                   ['detach', 'wrapper='])
    except Exception:
        usage()
        sys.exit(1)

    for o, val in opts:
        if o == '-j':
            jobid = val
        elif o == '-e':
            envs = val.split(',')
        elif o == '-l':
            lvl = CliUtils.get_logging_level(val)
        elif o == '-h':
            usage()
            sys.exit(0)
        elif o == '-t':
            hostname = val
        elif o == '--detach':
            detach = True
        elif o == '--wrapper':
            wrapper = val
        else:
            sys.stderr.write("Unrecognized option")
            usage()
            sys.exit(1)

    logging.basicConfig(level=lvl)

    s = Server(hostname)
    if detach:
        d = s.status(JOB, 'exec_host', id=jobid)
        if d and 'exec_host' in d[0]:
            hosts = ResourceResv.get_hosts(d[0]['exec_host'])
            svr_obj = Server(hosts[0])
            pconf = MoM(svr_obj, hosts[0]).pbs_conf['PBS_EXEC']
            # Use path to pbs_attach on natural vnode of the job
            pbs_attach = os.path.join(pconf, 'bin', 'pbs_attach')
            if wrapper is None:
                (fd, fn) = tempfile.mkstemp()
                os.write(fd, _wrapper_body)
                os.close(fd)
                os.chmod(fn, 0o755)
                wrapper = fn
                cleanup_wrapper = True
            a = [wrapper, pbs_attach, jobid] + args
            logging.debug(str(a))
            pbs_py_spawn(s._conn, jobid, a, envs)
            if cleanup_wrapper:
                os.remove(wrapper)
    else:
        pbs_py_spawn(s._conn, jobid, args, envs)

    sys.exit(0)