Fix issue 538 create vrf wo vni

[miguecor]

This PR fixes an issue when creating a new VRF without specifying a L3VNI.

• Before this change, this functionality was working on ND 3.1 and 3.2, but not on 4.1.
• After this change, this will work on all ND versions.

The issue was with the vrfVlanId parameter. When the value wasn't provided in the playbook, a default value of 0 was ussed. Now, if the vrfVlanId parameter is not provided, we transform it to an empty string (""). This default value works accross all 3 versions of ND.

Fix #538

[miguecor]

@allenrobel / @mikewiebe: This PR is ready for review.

[Copilot]

Pull request overview

This PR fixes an issue where creating a new VRF without specifying a L3VNI (vlan_id) fails on ND version 4.1, while working on versions 3.1 and 3.2. The fix ensures compatibility across all three ND versions by transforming the default vrfVlanId value from 0 to an empty string ("") for DCNM version 12+.

Key Changes

• Fixed a bug in get_next_vrf_id() where the retry loop would continue even after successfully retrieving a vrf_id, potentially overwriting valid values
• Modified diff_merge_create() to transform vrfVlanId from 0 to "" for DCNM version 12+, ensuring compatibility with ND 4.1

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[Copilot]

[nitpick] The inline conditional in the update() call is difficult to read and maintain. Consider extracting this logic to a separate variable before the update:

vrf_vlan_id_value = "" if template_conf["vrfVlanId"] == 0 else template_conf["vrfVlanId"]
template_conf.update(vrfVlanId=vrf_vlan_id_value)

This improves readability and makes the transformation logic more explicit.

Suggested change

	template_conf.update(
	vrfVlanId="" if template_conf["vrfVlanId"] == 0 else template_conf["vrfVlanId"]
	vrf_vlan_id_value = "" if template_conf["vrfVlanId"] == 0 else template_conf["vrfVlanId"]
	template_conf.update(
	vrfVlanId=vrf_vlan_id_value

[miguecor]

Implemented suggestion in ^9608cc6

[Copilot]

The conditional check template_conf["vrfVlanId"] == 0 doesn't handle the case where vrfVlanId might be None. When json_to_dict.get("vrfVlanId") is called at line 2246 without a default value, it returns None if the key is missing.

Consider using a more defensive check:

template_conf.update(
    vrfVlanId="" if template_conf.get("vrfVlanId") in [0, None] else template_conf["vrfVlanId"]
)

Or alternatively, ensure vrfVlanId has a default value at line 2246:

"vrfVlanId": json_to_dict.get("vrfVlanId", 0),

Suggested change

	vrfVlanId="" if template_conf["vrfVlanId"] == 0 else template_conf["vrfVlanId"]
	vrfVlanId="" if template_conf.get("vrfVlanId") in [0, None] else template_conf["vrfVlanId"]

[miguecor]

Implemented the defesive check in ^9608cc6

[mikewiebe]

Thanks @miguecor. We need to get PR #542 merged before we can merge this one since it has all of the changes required to support MCFG for VRFs.

[allenrobel]

Hi Miguel, this looks fine to me. I've also enabled Copilot review which generated a couple comments that look worth considering.

Thanks!

[allenrobel]

Is the update for isRPAbsent related to creating the VRF without VNI or is it a separate issue? It's fine that it's added here, but am rather just curious about it.

[miguecor]

It's not related. I just added the newline to standirize the elements inside the update function.