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Viewing changes to heat/openstack/common/excutils.py

  • Committer: Package Import Robot
  • Author(s): Chuck Short
  • Date: 2013-09-08 21:51:19 UTC
  • mto: This revision was merged to the branch mainline in revision 14.
  • Revision ID: package-import@ubuntu.com-20130908215119-7tcek6gn73275x5k
Tags: upstream-2013.2~b3
Import upstream version 2013.2~b3

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heat/openstack/common/excutils.py
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Exception related utilities.
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"""
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import contextlib
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import logging
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import sys
 
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import time
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import traceback
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from heat.openstack.common.gettextutils import _
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@contextlib.contextmanager
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def save_and_reraise_exception():
 
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from heat.openstack.common.gettextutils import _  # noqa
 
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class save_and_reraise_exception(object):
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    """Save current exception, run some code and then re-raise.
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    In some cases the exception context can be cleared, resulting in None
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    To work around this, we save the exception state, run handler code, and
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    then re-raise the original exception. If another exception occurs, the
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    saved exception is logged and the new exception is re-raised.
 
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    In some cases the caller may not want to re-raise the exception, and
 
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    for those circumstances this context provides a reraise flag that
 
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    can be used to suppress the exception.  For example:
 
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    except Exception:
 
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        with save_and_reraise_exception() as ctxt:
 
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            decide_if_need_reraise()
 
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            if not should_be_reraised:
 
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                ctxt.reraise = False
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    """
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    type_, value, tb = sys.exc_info()
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    try:
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        yield
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    except Exception:
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        logging.error(_('Original exception being dropped: %s'),
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                      traceback.format_exception(type_, value, tb))
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        raise
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    raise type_, value, tb
 
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    def __init__(self):
 
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        self.reraise = True
 
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    def __enter__(self):
 
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        self.type_, self.value, self.tb, = sys.exc_info()
 
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        return self
 
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    def __exit__(self, exc_type, exc_val, exc_tb):
 
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        if exc_type is not None:
 
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            logging.error(_('Original exception being dropped: %s'),
 
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                          traceback.format_exception(self.type_,
 
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                                                     self.value,
 
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                                                     self.tb))
 
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            return False
 
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        if self.reraise:
 
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            raise self.type_, self.value, self.tb
 
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def forever_retry_uncaught_exceptions(infunc):
 
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    def inner_func(*args, **kwargs):
 
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        last_log_time = 0
 
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        last_exc_message = None
 
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        exc_count = 0
 
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        while True:
 
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            try:
 
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                return infunc(*args, **kwargs)
 
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            except Exception as exc:
 
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                if exc.message == last_exc_message:
 
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                    exc_count += 1
 
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                else:
 
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                    exc_count = 1
 
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                # Do not log any more frequently than once a minute unless
 
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                # the exception message changes
 
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                cur_time = int(time.time())
 
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                if (cur_time - last_log_time > 60 or
 
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                        exc.message != last_exc_message):
 
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                    logging.exception(
 
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                        _('Unexpected exception occurred %d time(s)... '
 
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                          'retrying.') % exc_count)
 
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                    last_log_time = cur_time
 
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                    last_exc_message = exc.message
 
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                    exc_count = 0
 
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                # This should be a very rare event. In case it isn't, do
 
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                # a sleep.
 
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                time.sleep(1)
 
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    return inner_func