check_vault_health fails to fetch snap version

[Giuseppe Petralia]

This is happening on a jammy yoga cloud running:

charm-vault 1.8/stable

root@vault-1:~# snap info snapd | grep installed:
installed: 2.63 (21759) 40MB snapd

when run check_vault_health.py it returns critical

root@vault-1:~# /usr/lib/nagios/plugins/check_vault_health.py
CRITICAL: failed to fetch version of installed vault snap: Expecting value: line 1 column 1 (char 0)

This is because it fails to load the result when querying snapd socket [0]

snapd.recv returrns

['HTTP/1.1 200 OK\r',
 'Content-Type: application/json\r',
 'Date: Mon, 01 Jul 2024 11:29:26 GMT\r',
 'Transfer-Encoding: chunked\r',
 '\r',
 '8f4\r',
 '{"type":"sync","status-code":200,"status":"OK","result":{"id":"*********","title":"vault","summary":"...","icon":"https://dashboard.snapcraft.io/site_media/appmedia/2017/09/android-chrome-512x512.png","installed-size":290283520,"install-date":"2024-06-10T12:23:58.413633312Z","name":"vault","publisher":{"id":"canonical","username":"canonical","display-name":"Canonical","validation":"verified"},"developer":"canonical","status":"active","type":"app","base":"core18","version":"1.8.8","channel":"1.8/stable","tracking-channel":"1.8/stable","ignore-validation":false,"revision":"2066","confinement":"strict","private":false,"devmode":false,"jailmode":false,"apps":[{"snap":"vault","name":"vault"}],"mounted-from":"/var/lib/snapd/snaps/vault_2066.snap","contact":"","website":"https://github.com/canonical/snap-vault",}}\r',
 '0\r',
 '\r',
 '']

and the check takes [-1] which is ''

0. https://github.com/openstack/charm-vault/blob/stable/1.8/src/files/nagios/check_vault_health.py#L40

[Giuseppe Petralia (peppepetra)]

I can workaround changing

`snapd.recv(1024 * 1024).decode('utf-8').split('\n')[-1])`

with

`snapd.recv(1024 * 1024).decode('utf-8').split('\n')[-4])`

[Alex Kavanagh (ajkavanagh)]

The fix is on master at https://review.opendev.org/c/openstack/charm-vault/+/917766 - it just needs backporting to 1.8 ... 1.5.