Fix duplicate PSU creation when dmidecode reports identical PSUs

[shbatm]

Problem

Fixes #402

When dmidecode reports multiple power supplies with identical data (common with generic/placeholder values like "Default string"), the agent attempts to create duplicate power ports in Netbox. This causes a 400 error:

RequestError: The request failed with code 400 Bad Request: {'__all__': ['Power port with this Device and Name already exists.']}

Example dmidecode output:

System Power Supply
        Power Unit Group: 1
        Location: Default string
        Name: Default string
        Manufacturer: Default string
        Serial Number: Default string
        ...
(repeated 3 times identically)

Since all PSUs have empty serial numbers, they all get name="N/A" and identical descriptions, causing Netbox to reject the duplicates.

Solution

Added deduplication logic in power.py:18-64 get_power_supply() method:

• Track seen PSUs using a set of tuples: (serial_number, description, max_power)
• Skip any PSU that matches a previously seen combination
• Log skipped duplicates at DEBUG level

Changes

• Added seen_psus set to track unique PSU combinations
• Added duplicate check before appending PSU to the list
• Added debug logging for skipped duplicates

Testing

With this fix, systems reporting multiple identical PSUs will only create one power port in Netbox instead of failing on duplicate creation.

🤖 Generated with Claude Code