Add an import/export function for migrating "custom_fields" between instances of NetBox.

[bdlamprecht]

Issue type

[X] Feature request [ ] Bug report [ ] Documentation

Environment

• Python version: Python 2.7.12
• NetBox version: v2.2.8

Description

Currently, I'm working on migrating from a development instance of NetBox to a production instance and would like to move a number of custom_fields that I've created specific to this customer between these two instances. While I could manually create them by hand and at present would not be too much of a problem to do, once this goes live into production, I expect a lot of other needs are going to pop up requiring additional custom_fields which I'll have to test against in the my development instance. Also, inconsistencies may occur due to the "human element", so that is, in my opinion, a non-starter.

@lampwins helped kind of helped me do it with a pg_dump command and they were imported without any errors being reported, however, when I did this, the custom_fields were mapped to the incorrect models and I had to go into the Admin site and re-map them.

How difficult do you think this functionality would be to implement?

[lampwins]

To add some more context:

The issue we ran into is on the import, each custom field is sometimes (most of the time) mapped to the wrong netbox models. Best I can tell, this is due to ContentType id's for models being unique to a django installation (assumption on my part).

I think there is value in this feature from a netbox development and testing standpoint. As more people start to use netbox in automation flows, the need to run dev/test instances of netbox will certainly increase and so will the need to ensure those environments are identical.

[cimnine]

For inspiration how such a feature might work, and until such a feature is built-in to Netbox, you may find my little script for declaring and importing custom fields useful.

I don't usually write python code, so there might be a more elegant solution than this particular implementation, yet I think the concept is very intuitive.

[jeremystretch]

I'd like to avoid exposing custom fields as objects in the front end (to preserve the demarcation between data and schema), but we can probably implement some form of import/export function in the admin UI.

[cimnine]

Maybe this must not even be a feature in the UI but could be implemented through manage.py?

[jeremystretch]

Revisiting this. It seems like it's simple enough to do using Django's built-in dumpdata and loaddata management commands:

./manage.py dumpdata extras.customfield --indent 4 > customfields.json

./manage.py loaddata customfields.json

The content type IDs referenced by obj_type might need to be updated by hand if importing to a different NetBox instance, but I think that's a reasonable limitation given how infrequently it's likely to be used. Anything more involved is probably going to require some degree of custom scripting anyway.