wrapper python Daemon « subprocess E / S a expiré », ont besoin des directions

Question

Je ne suis pas très familier avec la façon de créer un démon en Python, donc Wheb essayer d'installer et d'exécuter un tiers open source TeX Python Wrapper i got mordre par une erreur que je fais, ni vraiment comprendre.

Je glissai impression pour aider le débogage.

Le fautif est appelé texdp.py

Quand je lance mathrand qui appelle texdp démarrage du serveur, je reçois l'erreur suivante

output_fds  {8: 'dvi', 5: 'log', 6: 'logfile', 7: 'err'}
input_fds  3
readable, writable [] [3]  outflds, inputflds:  [8, 5, 6, 7] [3]
pointer len_str:  0 63
folder fd:  7
readable, writable [5] []  outflds, inputflds:  [8, 5, 6, 7] []
pointer len_str:  63 63
folder fd:  7
readable, writable [5] []  outflds, inputflds:  [8, 5, 6, 7] []
pointer len_str:  63 63
folder fd:  5
readable, writable [] []  outflds, inputflds:  [8, 5, 6, 7] []
pointer len_str:  63 63
folder fd:  5
SUB IO ERROR: readable []  pointer == len_str: 63 , 63

Traceback (most recent call last):
  File "/usr/local/bin/mathtrand", line 18, in <module>
    server.start()
  File "/usr/local/lib/python2.6/dist-packages/mathtran/server.py", line 71, in start
    self.secplain.start()
  File "/usr/local/lib/python2.6/dist-packages/tex/texdp.py", line 159, in start
    self.process(self._params.start)
  File "/usr/local/lib/python2.6/dist-packages/tex/texdp.py", line 175, in process
    value = self._process(str + self._params.done, self._params.done_str)
  File "/usr/local/lib/python2.6/dist-packages/tex/texdp.py", line 210, in _process
    raise SubprocessError, 'subprocess I/O timed out'

La partie du code responsable est fixé et situé autour de la ligne 200 dans le procédé def _Process .

Je ne sais pas d'où commencer à chercher, et ce qui ne fonctionne cette erreur signifie vraiment. Toute aide est plus que bienvenue.

https: //texd.svn.sourceforge .net / svnroot / texd / trunk / py / tex / texdp.py

# Copyright: (c) 2007 The Open University, Milton Keynes, UK
# License: GPL version 2 or (at your option) any later version.
# Author: Jonathan Fine <jfine@pytex.org>, <J.Fine@open.ac.uk>

"""Wrapper around TeX process, to handle input and output.

Further comments to go here.
"""

__version__ = '$Revision: 116 $'[11:-2]
# $Source$

# TODO:  Move interface instances to elsewhere.
# TODO:  error recovery, e.g. undefined control sequence.
# TODO:  Abnormal exit is leaving orphaned processes.
# TODO:  Refactor _process into tex.util, share with metapostdp.

import os                               # Create directories and fifos
from select import select               # Helps handle i/o to TeX process
from tex.util import make_nonblocking   # For non-blocking file descriptor
from tex.util import DaemonSubprocess
from tex.dviopcode import FNT_DEF1, FNT_DEF4
import signal


class SubprocessError(EnvironmentError):

    pass

# TODO:  This belongs elsewhere.
class Interface(object):
    """Stores useful, but format specific, constants."""

    def __init__(self, **kwargs):
        # TODO:  Be more specific about the parameters.
        self.__dict__ = kwargs


# TeX knows about these fonts, but Python does not yet know.
# This list created by command: $tex --ini '&plain' \\dump
preloaded_fonts = ( 'cmr10', 'cmr9', 'cmr8', 'cmr7', 'cmr6', 'cmr5',
                    'cmmi10', 'cmmi9', 'cmmi8', 'cmmi7', 'cmmi6',
                    'cmmi5', 'cmsy10', 'cmsy9', 'cmsy8', 'cmsy7',
                    'cmsy6', 'cmsy5', 'cmex10', 'cmss10', 'cmssq8',
                    'cmssi10', 'cmssqi8', 'cmbx10', 'cmbx9', 'cmbx8',
                    'cmbx7', 'cmbx6', 'cmbx5', 'cmtt10', 'cmtt9',
                    'cmtt8', 'cmsltt10', 'cmsl10', 'cmsl9', 'cmsl8',
                    'cmti10', 'cmti9', 'cmti8', 'cmti7', 'cmu10',
                    'cmmib10', 'cmbsy10', 'cmcsc10', 'cmssbx10',
                    'cmdunh10', 'cmr7 scaled 2074',
                    'cmtt10 scaled 1440', 'cmssbx10 scaled 1440',
                    'manfnt', )

# Ship out a page that starts with a font def.
load_font_template = \
r'''%%
\begingroup
  \hoffset 0sp
  \voffset 0sp
  \setbox0\hbox{\font\tmp %s\relax\tmp M}%%
  \ht0 0sp
  \shipout\box 0
\endgroup
'''

secplain_load_font_template = \
r'''%%
\_begingroup
  \_hoffset 0sp
  \_voffset 0sp
  \_setbox0\_hbox{\_font\_tmp %s\_relax\_tmp M}%%
  \_ht0 0sp
  \_shipout\_box 0
\_endgroup
'''


plain = Interface(format='plain',
                  start = r'\shipout\hbox{}' '\n',
                  done = '\n' r'\immediate\write16{DONE}\read-1to\temp ' '\n',
                  done_str = 'DONE\n',
                  stop = '\end' '\n',
                  preloaded_fonts = preloaded_fonts,
                  load_font_template = load_font_template,
                  )

secplain = Interface(format='secplain',
                  start = r'\_shipout\_hbox{}' '\n',
                  done = '\n' r'\_immediate\_write16{DONE}\_read-1to\_temp ' '\n',
                  done_str = 'DONE\n',
                  stop = '\_end' '\n',
                  preloaded_fonts = preloaded_fonts,
                  load_font_template = secplain_load_font_template,
                  )



class Texdp(DaemonSubprocess):
    """Wrapper around TeX process that handles input and output.

    More comments go here.    
    """

    _fifos = ('texput.tex', 'texput.log', 'texput.dvi')

    def _make_args(self):

        # Don Knuth created plain.fmt, renamed by some to tex.fmt.
        fmt = self._params.format
        if fmt == 'plain' or fmt == 'tex':
            fmt = ''
        else:
            fmt = '--fmt=' + fmt

        # Build up the arguments list.
        args = ('tex', '--ipc',)
        args += ('--output-comment=""',) # Don't record time of run.
        if fmt:
            args += (fmt,)
        args += ('texput.tex',)
        return args

    def start(self):

        super(Texdp, self).start()      # Start the TeX process.

        # We will now initialise TeX, and conprocessnect to file descriptors.
        # We need to do some low-level input/output, in order to
        # manage long input strings.  Therefore, we use file
        # descriptors rather than file objects.

        # We map output fds to what will be a dictionary key.
        ofd = self._output_fd_dict = {}

        cwd = self._cwd                 # Shorthand.
        child = self._child 

        # For us, stdin and stdout are special.
        self._stdin = child.stdin.fileno()
        self._stdout = child.stdout.fileno()

        # Read stdout and stderr to 'log' and 'err' respectively.
        ofd[self._stdout] = 'log'
        ofd[child.stderr.fileno()] = 'err'

        # Open 'texput.tex', and block until it is available, which is
        # when TeX has started.  Then make 'texput.tex' non-blocking,
        # in case of a long write.
        self._texin = os.open(os.path.join(cwd, 'texput.tex'), os.O_WRONLY)
        make_nonblocking(self._texin)

        # Read 'texput.log' and 'texput.dvi' to 'logfile' and 'dvi'.
        for src, tgt in (('texput.log', 'logfile'), ('texput.dvi', 'dvi')):
            fd = os.open(os.path.join(cwd, src),
                         os.O_RDONLY|os.O_NONBLOCK)
            ofd[fd] = tgt

        # Ship out blank page, and initialise preloaded fonts.
        self.process(self._params.start)
        self._fontdefs = []
        for font_spec in self._params.preloaded_fonts:
            self.load_new_font(font_spec)

    def process(self, str):
        "Return dictionary with log, dvi, logfile and err entries."

        # TeX will read the data, following by the 'done' command.
        # The 'done' command will cause TeX to write the 'done_str',
        # which signals the end of the process.  It will also pause
        # TeX for input.

        # TODO: I do not know why the pause is required, but it is.
        # Remove it here and in the _params, and the program hangs.

        value = self._process(str + self._params.done, self._params.done_str)
        self._child.stdin.write('\n')   # TeX is paused for input.
        return value

    def _process(self, str, done_str):

        # Write str, and read output, until we are done.  Then gather
        # up the accumulated output, and return as a dictionary.  The
        # input string might be long.  Later, we might allow writing to
        # stdin, in response to errors.

        # Initialisation.
        print "output_fds ", self._output_fd_dict
        output_fds = self._output_fd_dict.keys()
        print "input_fds ", self._texin
        input_fds = [self._texin]

        accumulator = {}
        for fd in output_fds:
            accumulator[fd] = []

        pointer, len_str = 0, len(str)

        # The main input/ouput loop.
        # TOD0: magic number, timeout.
        done = False
        while not done:
            readable, writable = select(output_fds, input_fds, [], 0.1)[0:2]
            print "readable, writable", readable, writable, " outflds, inputflds: ", output_fds, input_fds
            print "pointer len_str: ", pointer, len_str
            print "folder fd: ", fd
            if not readable and pointer == len_str:
                print "SUB IO ERROR: readable", readable, " pointer == len_str:", pointer, ",", len_str
                os.kill(self._child.pid, signal.SIGKILL)
                self._child.wait()
                raise SubprocessError, 'subprocess I/O timed out'

            if pointer != len_str and writable:
                written = os.write(self._texin, str[pointer:pointer+4096])
                pointer += written
                if pointer == len_str:
                    input_fds = []

            for fd in readable:
                if self._child.poll() is not None:
                    raise SubprocessError, 'read from terminated subprocess'

                tmp = os.read(fd, 4096)
                if fd == self._stdout:
                    if tmp.endswith(done_str):
                        tmp = tmp[:-len(done_str)]
                        done = True
                accumulator[fd].append(tmp)

        if pointer != len_str:
            raise SystemError, "TeX said 'done' before end of input."

        # Join accumulated output, create and return ouput dictionary.
        value = {}
        for fd, name in self._output_fd_dict.items():
            value[name] = ''.join(accumulator[fd])
        return value

    def load_new_font(self, font_spec):
        """Tell both TeX and Python about a new font.

        Raises an exception if the font is not new.
        """

        # Ask TeX to load font, and ship out page that uses it.
        command mathtran= self._params.load_font_template % font_spec
        dvi = self.process(command)['dvi']

        bytes = dvi[45:-1]                  # Page body.
        opcode = ord(bytes[0])              # First opcode.

        # The first opcode should be a fontdef, which we extract.
        if FNT_DEF1 <= opcode <= FNT_DEF4:
            body_len = (2 + (opcode - FNT_DEF1)
                        + 12                # Checksum, scale, design size.
                        + 2)                # Length of 'area' and font name.

            name_len = ord(bytes[body_len - 2]) \
                       + ord(bytes[body_len - 1])

            fontdef = bytes[:body_len + name_len]
            self._fontdefs.append(fontdef)
            return

        else:
            raise ValueError, "font '%s' not new or not found" % font_spec

Answer 1

Le délai d'attente est basé sur l'appel select

readable, writable = select(output_fds, input_fds, [], 0.1)[0:2]

Le délai est de 0,1 secondes. Est-ce approprié?

Les noms de variables sont glauque ( « pointeur » peu de sens en Python). Cependant, il semble que si rien ne se passe sur 0,1 seconde, ressuscite « temps mort ».

---

Bizarrement, ce programme ouvre des fichiers pour communiquer avec un sous-processus. C'est très étrange d'être « partage » un fichier avec un sous-processus.

En général, nous faisons une de deux choses -. Tuyaux d'utiliser pour communiquer activement avec un sous-processus ou utiliser des fichiers de quitter la course subprocess sur son propre

Voici une conception plus simple.

1. Mettre l'entrée dans le fichier d'entrée.

2. Exécuter le sous-processus démon Tex jusqu'à ce qu'il se termine ou vous êtes fatigué d'attendre.

3. Si vous êtes fatigué d'attendre pour cela, tuez-le.

   Else

   • Regardez l'état de la fonction d'attente

   • Lire le fichier de sortie.

C'est à peu près tout ce que vous avez besoin. Et il n'y aura pas mystérieuse « pause », pas de bas niveau E / S, pas d'E / S non bloquant.

Si, pour une raison quelconque, vous devez communiquer avec le sous-processus, alors vous devriez envisager de remplacer les fichiers avec des tuyaux (qui ne sont pas partagées et sont probablement mieux pour ce que vous faites.)