"Late" check for module support

[jbemmel]

netlab/netsim/modules/__init__.py

Line 116 in 7fb94e8

check_supported_node_devices(topology) # A bit late, but we can do this check only after node data has been adjusted

The comment acknowledges that this is late in the process. I encountered this when adding stp support for OS10; the node_pre_transform hook gets called and reports an error, while the "real" error is that the STP module isn't (yet) supported by the device type to begin with

Can we do this check earlier? After expanding group data but before calling module hooks for the device would be better imho - I'd like to be able to assume module support has been validated for the device being operated on

[jbemmel]

Any reason this wouldn't work?

[ipspace]

DHCP module adding "dhcp" to the list of node modules if you ask for a DHCP client on a link?

[ipspace]

I encountered this when adding stp support for OS10; the node_pre_transform hook gets called and reports an error, while the "real" error is that the STP module isn't (yet) supported by the device type to begin with

Maybe you should ask yourself "why did the node_pre_transform report an error". Before the data validation routines are called you have to assume the data is potentially corrupt (I told you that when discussing the LAG module).

[jbemmel]

Then maybe we should move that check from node_pre_transform to node_post_transform (and remove the node_pre_transform hook because that's all it does)

[jbemmel]

And there may be more cases like that: #1488