codekingpro/portable-devtools

1"""The debug module contains utilities and functions for better2debugging Eventlet-powered applications."""3from __future__ import print_function4 5import os6import sys7import linecache8import re9import inspect10 11__all__ = ['spew', 'unspew', 'format_hub_listeners', 'format_hub_timers',12           'hub_listener_stacks', 'hub_exceptions', 'tpool_exceptions',13           'hub_prevent_multiple_readers', 'hub_timer_stacks',14           'hub_blocking_detection']15 16_token_splitter = re.compile('\W+')17 18 19class Spew(object):20 21    def __init__(self, trace_names=None, show_values=True):22        self.trace_names = trace_names23        self.show_values = show_values24 25    def __call__(self, frame, event, arg):26        if event == 'line':27            lineno = frame.f_lineno28            if '__file__' in frame.f_globals:29                filename = frame.f_globals['__file__']30                if (filename.endswith('.pyc') or31                        filename.endswith('.pyo')):32                    filename = filename[:-1]33                name = frame.f_globals['__name__']34                line = linecache.getline(filename, lineno)35            else:36                name = '[unknown]'37                try:38                    src = inspect.getsourcelines(frame)39                    line = src[lineno]40                except IOError:41                    line = 'Unknown code named [%s].  VM instruction #%d' % (42                        frame.f_code.co_name, frame.f_lasti)43            if self.trace_names is None or name in self.trace_names:44                print('%s:%s: %s' % (name, lineno, line.rstrip()))45                if not self.show_values:46                    return self47                details = []48                tokens = _token_splitter.split(line)49                for tok in tokens:50                    if tok in frame.f_globals:51                        details.append('%s=%r' % (tok, frame.f_globals[tok]))52                    if tok in frame.f_locals:53                        details.append('%s=%r' % (tok, frame.f_locals[tok]))54                if details:55                    print("\t%s" % ' '.join(details))56        return self57 58 59def spew(trace_names=None, show_values=False):60    """Install a trace hook which writes incredibly detailed logs61    about what code is being executed to stdout.62    """63    sys.settrace(Spew(trace_names, show_values))64 65 66def unspew():67    """Remove the trace hook installed by spew.68    """69    sys.settrace(None)70 71 72def format_hub_listeners():73    """ Returns a formatted string of the current listeners on the current74    hub.  This can be useful in determining what's going on in the event system,75    especially when used in conjunction with :func:`hub_listener_stacks`.76    """77    from eventlet import hubs78    hub = hubs.get_hub()79    result = ['READERS:']80    for l in hub.get_readers():81        result.append(repr(l))82    result.append('WRITERS:')83    for l in hub.get_writers():84        result.append(repr(l))85    return os.linesep.join(result)86 87 88def format_hub_timers():89    """ Returns a formatted string of the current timers on the current90    hub.  This can be useful in determining what's going on in the event system,91    especially when used in conjunction with :func:`hub_timer_stacks`.92    """93    from eventlet import hubs94    hub = hubs.get_hub()95    result = ['TIMERS:']96    for l in hub.timers:97        result.append(repr(l))98    return os.linesep.join(result)99 100 101def hub_listener_stacks(state=False):102    """Toggles whether or not the hub records the stack when clients register103    listeners on file descriptors.  This can be useful when trying to figure104    out what the hub is up to at any given moment.  To inspect the stacks105    of the current listeners, call :func:`format_hub_listeners` at critical106    junctures in the application logic.107    """108    from eventlet import hubs109    hubs.get_hub().set_debug_listeners(state)110 111 112def hub_timer_stacks(state=False):113    """Toggles whether or not the hub records the stack when timers are set.114    To inspect the stacks of the current timers, call :func:`format_hub_timers`115    at critical junctures in the application logic.116    """117    from eventlet.hubs import timer118    timer._g_debug = state119 120 121def hub_prevent_multiple_readers(state=True):122    """Toggle prevention of multiple greenlets reading from a socket123 124    When multiple greenlets read from the same socket it is often hard125    to predict which greenlet will receive what data.  To achieve126    resource sharing consider using ``eventlet.pools.Pool`` instead.127 128    But if you really know what you are doing you can change the state129    to ``False`` to stop the hub from protecting against this mistake.130    """131    from eventlet.hubs import hub132    hub.g_prevent_multiple_readers = state133 134 135def hub_exceptions(state=True):136    """Toggles whether the hub prints exceptions that are raised from its137    timers.  This can be useful to see how greenthreads are terminating.138    """139    from eventlet import hubs140    hubs.get_hub().set_timer_exceptions(state)141    from eventlet import greenpool142    greenpool.DEBUG = state143 144 145def tpool_exceptions(state=False):146    """Toggles whether tpool itself prints exceptions that are raised from147    functions that are executed in it, in addition to raising them like148    it normally does."""149    from eventlet import tpool150    tpool.QUIET = not state151 152 153def hub_blocking_detection(state=False, resolution=1):154    """Toggles whether Eventlet makes an effort to detect blocking155    behavior in an application.156 157    It does this by telling the kernel to raise a SIGALARM after a158    short timeout, and clearing the timeout every time the hub159    greenlet is resumed.  Therefore, any code that runs for a long160    time without yielding to the hub will get interrupted by the161    blocking detector (don't use it in production!).162 163    The *resolution* argument governs how long the SIGALARM timeout164    waits in seconds.  The implementation uses :func:`signal.setitimer`165    and can be specified as a floating-point value.166    The shorter the resolution, the greater the chance of false167    positives.168    """169    from eventlet import hubs170    assert resolution > 0171    hubs.get_hub().debug_blocking = state172    hubs.get_hub().debug_blocking_resolution = resolution173    if not state:174        hubs.get_hub().block_detect_post()175