port_popen.py

#! /usr/bin/env python3
# process the submit command from Cluster in one of the following ways
#   1. just execute the command directly by calling popen
#   2. execute a pre-submit python script to support resume
#
import     sys
import     os.path
import     os
import     subprocess

def popen(cmd, sout=subprocess.PIPE, serr=subprocess.PIPE, pshell=True):
    #
    try:
        process = subprocess.Popen(cmd, stdout=sout, stderr=serr, shell=pshell)
    except Exception as e:
        emsg = ">>> Error: Popen exception: " + str(e) + "\ncommand: " + cmd
        status = 1
        return_msg = emsg
        return (return_msg, status)

    status = process.wait()
    if status != 0:
        if serr == subprocess.PIPE:
            pipe = process.stderr
            eMsg = pipe.readline()
            # compatibility p2/p3: byte seq or string converts to string
            eMsg = bytes(eMsg).decode()
            if len(eMsg):
                eMsg = ">>> Error: " + eMsg
            else:
                eMsg = ""
        elif serr != sys.stderr:
            eMsg = ">>> Error executing cmd: "  + cmd + "\n(See log file for details.)"
        else:
            eMsg = ""
        return (eMsg, status)
    # if pipes, read the results of popen
    if sout == subprocess.PIPE:
        pipe = process.stdout
        popen_results = pipe.readline()
        # compatibility p2/p3: byte seq or string converts to string
        popen_results = bytes(popen_results).decode()
        popen_results = popen_results.strip(' \t\n\r')
    # else results have been sent to stdout
    else:
        popen_results = ""
    return (popen_results, status)

def popen_stdout(cmd, logfile=None, jobname=None, shell=True):
    sout = sys.stdout
    serr = sys.stderr
    # redirect stdout/stderr to file
    if logfile != None:
        flog = open ( logfile, 'w' )
        sout = flog
        serr = flog

    (rmsg, status) = popen(cmd, sout=sout, serr=serr, pshell=shell)
    if logfile != None:
        flog.close()
    return (rmsg, status)