def raise_with_cause(exc_cls, message, *args, **kwargs):
"""Helper to raise + chain exceptions (when able) and associate a *cause*.
NOTE(harlowja): Since in py3.x exceptions can be chained (due to
:pep:`3134`) we should try to raise the desired exception with the given
*cause* (or extract a *cause* from the current stack if able) so that the
exception formats nicely in old and new versions of python. Since py2.x
does **not** support exception chaining (or formatting) our root exception
class has a :py:meth:`~taskflow.exceptions.TaskFlowException.pformat`
method that can be used to get *similar* information instead (and this
function makes sure to retain the *cause* in that case as well so
that the :py:meth:`~taskflow.exceptions.TaskFlowException.pformat` method
shows them).
:param exc_cls: the :py:class:`~taskflow.exceptions.TaskFlowException`
class to raise.
:param message: the text/str message that will be passed to
the exceptions constructor as its first positional
argument.
:param args: any additional positional arguments to pass to the
exceptions constructor.
:param kwargs: any additional keyword arguments to pass to the
exceptions constructor.
"""
if not issubclass(exc_cls, TaskFlowException):
raise ValueError("Subclass of taskflow exception is required")
excutils.raise_with_cause(exc_cls, message, *args, **kwargs)
def raise_with_cause(exc_cls, message, *args, **kwargs):
"""Helper to raise + chain exceptions (when able) and associate a *cause*.
NOTE(harlowja): Since in py3.x exceptions can be chained (due to
:pep:`3134`) we should try to raise the desired exception with the given
*cause* (or extract a *cause* from the current stack if able) so that the
exception formats nicely in old and new versions of python. Since py2.x
does **not** support exception chaining (or formatting) our root exception
class has a :py:meth:`~taskflow.exceptions.TaskFlowException.pformat`
method that can be used to get *similar* information instead (and this
function makes sure to retain the *cause* in that case as well so
that the :py:meth:`~taskflow.exceptions.TaskFlowException.pformat` method
shows them).
:param exc_cls: the :py:class:`~taskflow.exceptions.TaskFlowException`
class to raise.
:param message: the text/str message that will be passed to
the exceptions constructor as its first positional
argument.
:param args: any additional positional arguments to pass to the
exceptions constructor.
:param kwargs: any additional keyword arguments to pass to the
exceptions constructor.
"""
if not issubclass(exc_cls, TaskFlowException):
raise ValueError("Subclass of taskflow exception is required")
excutils.raise_with_cause(exc_cls, message, *args, **kwargs)
def raise_with_cause(exc_cls, message, *args, **kwargs):
"""Helper to raise + chain exceptions (when able) and associate a *cause*.
**For internal usage only.**
NOTE(harlowja): Since in py3.x exceptions can be chained (due to
:pep:`3134`) we should try to raise the desired exception with the given
*cause*.
:param exc_cls: the :py:class:`~tooz.ToozError` class to raise.
:param message: the text/str message that will be passed to
the exceptions constructor as its first positional
argument.
:param args: any additional positional arguments to pass to the
exceptions constructor.
:param kwargs: any additional keyword arguments to pass to the
exceptions constructor.
"""
if not issubclass(exc_cls, tooz.ToozError):
raise ValueError("Subclass of tooz error is required")
excutils.raise_with_cause(exc_cls, message, *args, **kwargs)
def raises_chained():
try:
raise Fail2("I have been broken")
except Fail2:
excutils.raise_with_cause(Fail1, "I was broken")
def raise_delivery_failure(exc):
excutils.raise_with_cause(DeliveryFailure,
encodeutils.exception_to_unicode(exc),
cause=exc)
def raise_delivery_failure(exc):
excutils.raise_with_cause(DeliveryFailure,
encodeutils.exception_to_unicode(exc),
cause=exc)
def raises_chained():
try:
raise Fail2("I have been broken")
except Fail2:
excutils.raise_with_cause(Fail1, "I was broken")
