do-backup action not working

[Linda Guo]

Tried to install juju-backup-all charm on bionic from stable channel version 27 and 28. Installation failed with:

unit-juju-backup-all-0: 23:21:12 WARNING unit.juju-backup-all/0.install from cryptography.hazmat.primitives.asymmetric import (
unit-juju-backup-all-0: 23:21:12 WARNING unit.juju-backup-all/0.install File "/var/lib/juju/agents/unit-juju-backup-all-0/charm/venv/cryptography/hazmat/primitives/asymmetric/utils.py", line 6, in <module>
unit-juju-backup-all-0: 23:21:12 WARNING unit.juju-backup-all/0.install from cryptography.hazmat.bindings._rust import asn1
unit-juju-backup-all-0: 23:21:12 WARNING unit.juju-backup-all/0.install ImportError: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.28' not found (required by /var/lib/juju/agents/unit-juju-backup-all-0/charm/venv/cryptography/hazmat/bindings/_rust.abi3.so)
unit-juju-backup-all-0: 23:21:13 ERROR juju.worker.uniter.operation hook "install" (via hook dispatching script: dispatch) failed: exit status 1

Then, tried to install from edge channel (version 33). Installation succeeded but when running 'do-backup' action, it's stuck ( I have waited more than 1 hour). The juju deployment is small, it just has a single machine and single application. Nothing output in juju log. No backup files generated in /opt/backups/

[Linda Guo (lihuiguo)]

install hook worked on focal but do-backup action also stuck

[Sudeep Bhandari (sudeephb)]

This comes from juju-backup-all as trying to backup using the snap also gets stuck.

[Sudeep Bhandari (sudeephb)]

This bug is introduced by the commit
https://git.launchpad.net/juju-backup-all/commit/?id=6ac195c1e691155bf4d1c58a3cad3ee3ea450360

[JamesLin (jneo8)]

Not very sure the reason. But the juju version in /var/lib/juju/agents/unit-juju-backup-all-2/charm/venv is newest version instead of 2.9.9.

And the stuck reason is because of the python-libjuju [0] is being deprecated. It's used in juju-backup-all snap when connect to controller [1] . Also the behavior is different in newest version.

---
[0]: https://github.com/juju/python-libjuju/blob/master/juju/loop.py
[1]: https://git.launchpad.net/juju-backup-all/tree/jujubackupall/process.py#n27

[JamesLin (jneo8)]

Update:

The reason it stuck is not just because of the rpe schema version. Also jasyncio.run function provided by python-libjuju.

Details here: https://github.com/juju/python-libjuju/issues/763