Test of running Nuke in a psuedoterminal to capture progress info

nuke_pty_test.py

"""Test of running Nuke in a psuedoterminal, in order to capture the
7% done, Time to go: 17 minutes, 53 seconds
..output
"""


raise Exception("This probably doesn't work very reliably, barely tested")


import os
import sys
import pty
import subprocess


def run_in_pty(cmd, handle_stdout="supress"):
    if handle_stdout not in [
        "supress", # Hide stderr
        "untouched", # Let stderr go to output as usual
        "debug", # Output stderr as usual, but show repr() of it, with "stderr:" prefix
        ]:
        raise ValueError("Invalid option for handle_stdout arg")

    # Create psuedoterminals for stdout and stderr
    stdout_master, stdout_slave = pty.openpty()
    stderr_master, stderr_slave = pty.openpty()

    # Create process
    p = subprocess.Popen(cmd,
                         stdout=stdout_slave,
                         stderr=stderr_slave,
                         )

    # Create Python file objects for terminal
    bufsize=0
    stdout = os.fdopen(stdout_master, 'rb', bufsize)
    stderr = os.fdopen(stderr_master, 'rb', bufsize)

    # Begin reading output
    import select, errno
    read_set = [stdout_master, stderr_master]

    while read_set:
        try:
            ret = select.select(read_set, [], [])
        except select.error, e:
            # EINTER means try again
            if e.args[0] == errno.EINTR:
                continue
            else:
                raise

        # Got data from stdout or stderr
        for fd in ret[0]:
            if stdout is not None and not stdout.closed and fd == stdout.fileno():
                read = stdout.read(1)#line()
                if read == "": # EOF (a blank line would be "\n")
                    # Stream complete
                    read_set.remove(stdout_master)
                    stdout.close()
                else:
                    # New output to stdOUT.
                    #sys.stdout.write("stdout: %r\n" % read)
                    yield read

            elif not stderr.closed and fd == stderr.fileno():
                read = stderr.readline()
                if read == "":
                    # Stream complete
                    read_set.remove(stderr_master)
                    stderr.close()
                else:
                    # New output to stdERR
                    if handle_stdout == "supress":
                        pass
                    elif handle_stdout == "untouched":
                        sys.stderr.write(read)
                    elif handle_stdout == "debug":
                        sys.stderr.write("stderr: %r\n" % read)

    # End of output, wait for process to terminate
    p.wait()
    if p.returncode != 0:
        raise subprocess.CalledProcessError("Process return exit code %s" % p.returncode,
                                 p.returncode,
                                 None)



def split_by_cr(iterable):
    """Loops over the iterable, yielding lines denoted by the
    carridge-return "\r" instead of newline "\n"
    """

    linebuf = []
    for x in iterable:
        if x == "\r":
            # Carridge return
            yield "".join(linebuf)
            linebuf = []
            # Check if next character is a newline, if so, ignore it
            n = next(iterable)
            if n == "\n":
                pass
            else:
                linebuf.append(n)
        else:
            linebuf.append(x)


# Crude progress parser
import re
prog_matcher = re.compile(r".*(\d+)% done, ") # '  1% done, Time to go: 45 seconds        '


for line in split_by_cr(run_in_pty(sys.argv[1:])):

    m = prog_matcher.match(line)
    if m:
        print "%d%%" % (int(m.group(1)))
    elif "Writing" in line:
        print line