Handling Device Quirks

Individual devices supported by netlab might have implementation details that are not recognized by the netlab core, configuration modules, or device feature flags. These details should be handled by device quirks modules.

The device quirks are checked at the very end of the data transformation (after provider post_transform hook). When a quirks function modifies node data, the modified data will be used to generate provider configuration files or Ansible inventory.


A device quirks module must reside in netsim/quirks directory and have the same name as the device (example: eos.py for Arista EOS).

It must define a descendant of the _Quirks module with device_quirks method:

class EOS(_Quirks):

  def device_quirks(self, node: Box, topology: Box) -> None:

You should define a new function for every quirk you want to handle, and call those functions from the device_quirks method. It probably makes sense to use node.module attribute when deciding which functions to call, for example:

class EOS(_Quirks):

  def device_quirks(self, node: Box, topology: Box) -> None:
    mods = node.get('module',[])
    if 'evpn' in mods:
      if common.debug_active('quirks'):
        print(f'Arista EOS: Checking MPLS VLAN bundle for {node.name}')

The individual quirks functions should check the relevant node data (example: vlan.mode must be set to bridge on Arista EOS if vlan.evpn.bundle is set) and make changes to node data structure if needed (example: remove Vlan{vlan.id} interfaces on Arista EOS for VLANs in an EVPN/MPLS VLAN bundle).

Use common.error function to report errors that should terminate the data transformation.