Allow for overriding the limit for truncating exceptions

[wyegelwel]

Currently, distributed will truncate an exception if it is longer than 1000 characters (lines?)

distributed/distributed/core.py

Line 843 in dbb529b

e2 = truncate_exception(e, 1000)

From a user perspective this is very jarring because it makes debugging nearly impossible and it isn't obvious dask is the one truncating the error. Googling for "Long error message" doesn't yield anything useful. Having a way to override the limit (and informing the user how to do that in the error message) would make it possible for users to proceed when this problem occurs.

[mrocklin]

Making that configurable makes sense to me. We should probably put an entry under `distributed.worker.maximum-error-length` or something similar (See http://dask.pydata.org/en/latest/configuration.html). Would you be interested in making this change and submitting a pull request?

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On Wed, Sep 12, 2018 at 4:15 PM, wyegelwel ***@***.***> wrote: Currently, distributed will truncate an exception if it is longer than 1000 characters (lines?) https://github.com/dask/distributed/blob/ dbb529b/distributed/core.py#L843 From a user perspective this is very jarring because it makes debugging nearly impossible and it isn't obvious dask is the one truncating the error. Googling for "Long error message" doesn't yield anything useful. Having a way to override the limit (and informing the user how to do that in the error message) would make it possible for users to proceed when this problem occurs. — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#2248>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AASszFiJ4K2tYzZH3Vr8KxGFv5YVzED6ks5uaWtLgaJpZM4WmFuM> .

[mrocklin]

@wyegelwel is this something that you're able to contribute?

[OliverHofkens]

A quick scan through the code shows that this has been implemented in the meantime.
truncate_exception is only used once, and the n parameter is fetched from the distributed.admin.max-error-length config option:

distributed/distributed/core.py

Lines 1195 to 1199 in 4e2c1b3

	MAX_ERROR_LEN = dask.config.get("distributed.admin.max-error-length")
	tblib.pickling_support.install(e, *collect_causes(e))
	tb = get_traceback()
	tb_text = "".join(traceback.format_tb(tb))
	e = truncate_exception(e, MAX_ERROR_LEN)

I believe this issue can be closed 🎉

[fjetter]

Thanks for catching this @OliverHofkens