Getting spurious errors from python-libjuju: [WARNING] Unknown delta type: id

[Drew Freiberger]

During zaza testing, inside of a model.block_until() loop, we're seeing the following happening on juju 2.8.5 models.

[WARNING] Unknown delta type: id

It appears the exception is coming from Model._watch():
https://github.com/juju/python-libjuju/blob/133433a910e5d62de8959c3ffed5736598b05c1f/juju/model.py#L905

And that the list of known delta types is listed here:
https://github.com/juju/python-libjuju/blob/9e31ce1e79c9954ef226cb3076de66ddaafcb3ee/juju/delta.py#L109

This is causing very large logs during functional testing of openstack and openstack related charms utilizing the juju/zaza model block_until*() functions.

[John A Meinel (jameinel)]

You didn't include the content of the exception, which would have e.args[0] indicating the delta type that lib juju isn't understanding.

[Drew Freiberger (afreiberger)]

Sorry, it's in the title of the bug. the unknown type is "id"

[WARNING] Unknown delta type: id

[Drew Freiberger (afreiberger)]

To replicate:

charm pull elasticsearch
cd elasticsearch
make submodules
make functional

[Pen Gale (pengale)]

We just had a conversation about this. The warning occurs because python-libjuju needs to be updated to handle some of the most recent changes.

The warning is harmless, but annoying. We need to both update python-libjuju and possibly be quieter about such errors in the future.

[Simon Richardson (simonrichardson)]

The way we're tackling this is by adding a mode to juju that allows us to tell consumers of the model what mode to interpret the AllWatcher API.

Juju fix: https://github.com/juju/juju/pull/12183
Pylibjuju fix: https://github.com/juju/python-libjuju/pull/451

Interesting note: Turning on strict mode highlighted that we handled models incorrectly coming from the AllWatcher deltas, so that's a win!