デーモンpythonラッパー "サブプロセスI/Oタイムアウト"

Question

私はPythonでデーモンを作成する方法に慣れていないので、サードパーティのオープンソースTeX Python Wrapperをインストールして実行しようとしています。私は本当に理解していないエラーで噛み付く。

デバッグに役立つ印刷物を追加しました。

私はtexdpサーバーの開始を呼び出すmathrandを実行すると、障害のある1がtexdp.py

と呼ばれ、 私が責任を負うコードの一部が取り付けられており、周囲に配置されて

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' 

次のエラーを取得しますメソッドdef _processの行200

私はどこから見始めるべきか分からず、このエラーはどういう意味ですか。 ご迷惑をおかけして申し訳ございません。

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

タイムアウトがタイムアウトは0.1秒であるselectコール

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

に基づいています。これは適切ですか？

変数名は暗いです（「ポインタ」はPythonではほとんど意味がありません）。しかし、0.1秒で何も起こらなければ、「タイムアウト」が発生するように見える。

---

このプログラムは、奇妙なことに、サブプロセスと通信するためのファイルを開きます。これは、ファイルをサブプロセスと「共有する」ことは非常に奇妙です。

通常は、パイプを使用してサブプロセスとアクティブに通信したり、ファイルを使用してサブプロセスを単独で実行したりします。

ここでは、よりシンプルなデザインです。

1. 入力を入力ファイルに入れます。

2. テクスチャデーモンのサブプロセスが終了するか、それを待つのがうまくいくまで実行してください。

3. あなたがそれを待ってうんざりするなら、それを殺す。

   エルス

   • ウェイト機能から状況を見

   • 出力ファイルをお読みください。ほとんどすべてが必要だ

。また、不思議な「一時停止」もなく、低レベルのI/Oも、非ブロックI/Oもありません。何らかの理由であなたがサブプロセスと通信する必要がある、場合

、あなたはパイプを持つファイルを置き換えることを見て（共有されていないと、何のためにあなたがやっているため、おそらく優れています。）必要があります