Python: T7740: Update dict_search to return optional default value

[l0crian1]

Change summary

I've often found myself needing to return a default value when using dict_search, requiring me to use .get() instead, which makes for inconsistent code for ultimately the same function.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

https://vyos.dev/T7740

Related PR(s)

How to test / Smoketest result

Python Test script:

from vyos.utils.dict import dict_search

test_data = {
    "interfaces": {
        "ethernet": {
            "eth0": {
                "address": "192.0.2.1/24",
                "description": "WAN uplink"
            },
            "eth1": {
                "address": "10.0.0.1/24",
                "description": "LAN"
            }
        }
    },
    "system": {
        "hostname": "vyos-router"
    }
}

print(dict_search("interfaces.ethernet.eth0.address", test_data))       # 192.0.2.1/24
print(dict_search("interfaces.ethernet.eth1.description", test_data))   # LAN
print(dict_search("interfaces.ethernet.eth3", test_data))               # None
print(dict_search("system.hostname", test_data))                        # vyos-router
print(dict_search("system.login", test_data, "not found"))      # not found

Results:

root@vyos:/home/vyos# python3 test.py
192.0.2.1/24
LAN
None
vyos-router
not found

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• I have run the components SMOKETESTS if applicable
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

👍
No issues in PR Title / Commit Title

[sarthurdev]

Useful extension to dict_search

[c-po]

I've often found myself needing to return a default value when using dict_search, requiring me to use .get() instead, which makes for inconsistent code for ultimately the same function.

I found myself in the same situation but was to biased to find such an easy solution. Thanks! As you already outlined some testcases - please be so kind and extend the build time test suite to cover these as well everytime. Those are run by make test or make all during DEB package assembly.

https://github.com/vyos/vyos-1x/blob/current/src/tests/test_dict_search.py

[c-po]

Requested change addressed

[github-actions]

CI integration 👍 passed!

Details

CI logs

• CLI Smoketests (no interfaces) 👍 passed
• CLI Smoketests VPP 👍 passed
• CLI Smoketests (interfaces only) 👍 passed
• Config tests 👍 passed
• Config tests VPP 👍 passed
• RAID1 tests 👍 passed
• TPM tests 👍 passed