Scope and purpose

Resolves #1996

This PR adds support for searching for serial numbers that are no longer associated with equipment in the database, such as Netboxes, modules or power supplies. These are named "Inactive Devices", as they are not registered on any component in the system. This is necessary to enable users of NAV to find alert history events for devices that have been "disconnected" from a component.

Screenshots

How to test

Adding alerts to an inactive device

Your local database is unlikely to contain any history for inactive devices, as the alert history is empty by default when dumping from a production database. I solved this by finding an unused device and adding a few alerts manually. You can use this python snippet (when using django-admin shell)

from nav.models.event import AlertHistory
from datetime import datetime, timedelta

serial = 'SMC1145003Z'
device = AlertHistory.objects.filter(device__serial=serial).first()

AlertHistory.objects.create(device=device, source_id='pping', start_time=datetime.now(), end_time=datetime.now() + timedelta(days=2), event_type_id='boxState', alert_type_id=1, value=42)
AlertHistory.objects.create(device=device, source_id='pping', start_time=datetime.now(), end_time=datetime.now() + timedelta(days=2), event_type_id='boxState', alert_type_id=3, value=42)

Querying the database for inactive devices

You can query the database by using the shell and the Device model, or with a sql query. Here are the two options.

Device.objects.filter(serial__isnull=False, entities__isnull=True, power_supplies_or_fans__isnull=True, modules__isnull=True)

SELECT d.*
FROM manage.device d
LEFT JOIN manage.netboxentity nbe ON nbe.deviceid = d.deviceid
LEFT JOIN manage.module m ON m.deviceid = d.deviceid
LEFT JOIN manage.powersupply_or_fan ps ON ps.deviceid = d.deviceid
WHERE d.serial IS NOT NULL
  AND nbe.deviceid IS NULL
  AND m.deviceid IS NULL
  AND ps.deviceid IS NULL;

NOTE: They don't return the same number of records, which is strange.

Contributor Checklist

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More information about contributing to NAV can be found in the
Hacker's guide to NAV.

• Added a changelog fragment for towncrier
• Added/amended tests for new/changed code
• Added/changed documentation
• Linted/formatted the code with ruff, easiest by using pre-commit
• Wrote the commit message so that the first line continues the sentence "If applied, this commit will ...", starts with a capital letter, does not end with punctuation and is 50 characters or less long. See https://cbea.ms/git-commit/
• Based this pull request on the correct upstream branch: For a patch/bugfix affecting the latest stable version, it should be based on that version's branch (<major>.<minor>.x). For a new feature or other additions, it should be based on master.
• If applicable: Created new issues if this PR does not fix the issue completely/there is further work to be done
• If it's not obvious from a linked issue, described how to interact with NAV in order for a reviewer to observe the effects of this change first-hand (commands, URLs, UI interactions)
• If this results in changes in the UI: Added screenshots of the before and after
• If this adds a new Python source code file: Added the boilerplate header to that file