Linking to NetBox Objects

Scenario: you want to record the static routes configured on each device. Each route belongs to one device and optionally a VRF. You'll also link devices to the support contracts that cover them, so the link can be followed from either side.

You'll use: object fields that point at NetBox models, reverse relation names, the Custom Objects tab, and a NetBox custom field that points at a Custom Object Type.

Before You Start

• At least one device exists in NetBox.
• For the second half, the Support Contract type from A self-contained object type exists, with a contract or two.
• Your user can add Custom Object Types and fields, and NetBox custom fields.

Steps

1. Create the Static Route Type

1. Go to Custom Objects > Custom Object Types and click Add.
2. Set Internal name to static_route, Display name (singular) to Static Route and Display name (plural) to Static Routes, then click Create.

2. Add the Fields

For each row, click Add on the type's page, choose Field, fill in the values, and click Create:

On delete behavior: Cascade deletes a device's routes when the device is deleted. The default, Set null, would leave routes with no device, which this field doesn't allow.

3. Add Routes to a Device

1. Under Custom Objects > Objects, click the + next to Static Routes.
2. Enter a destination and next hop, and pick the device (and a VRF, if you use them).
3. Click Create & Add Another, and add a second route for the same device.

4. See the Routes from the Device

1. Open the device's page. A Custom Objects tab shows how many custom objects reference it.
2. Click the tab. Both routes are listed, with the field that links them (Device).
3. Use the tab's search to narrow the list, and a route's edit button to change it. A type filter appears once custom objects of more than one type link to the device, and a tag filter once they have tags.

5. Link Devices to Support Contracts

The device field above is defined on the custom object. To put a field on the device instead, add a NetBox custom field that points at a Custom Object Type:

1. Go to Customization > Custom Fields and click Add.

2. Fill in:

   Field	Value
   Object types	DCIM > Device
   Name	support_contract
   Label	Support contract
   Type	Object
   Related object type	Custom Objects > Support Contract

3. Click Create.

4. Edit a device, choose a contract in Support contract (under Custom Fields, near the bottom of the form), and save. The device's page shows the contract under Custom Fields, linked to the contract's page.

5. The contract's page doesn't list the devices that link to it this way. To find them, filter the device list by the custom field: on Devices > Devices, open the Filters tab and choose the contract under Support contract.

6. Follow the Link in a Template or Script (Optional)

The Reverse relation name makes the routes available from the device, e.g. in an export template for devices. Go to Customization > Export Templates, click Add, set Name to Static routes, Object types to DCIM > Device, and Template code to:

{% for device in queryset %}
{{ device.name }}
{%- for route in device.static_routes.all() %}
  ip route {{ route.destination }} {{ route.next_hop }}
{%- endfor %}
{% endfor %}

Then, on the device list, choose Export > Static routes. The file lists each device followed by its routes:

core-sw-01
  ip route 10.20.0.0/16 192.0.2.1
  ip route 0.0.0.0/0 198.51.100.1

Result

Static routes are recorded against devices, the routes appear on each device's Custom Objects tab, and devices link to the contracts that cover them.

See Also

• Custom Objects Tab
• Field Attributes: Object Reference Fields
• Referencing more than one kind of object, for a field that can point at a device or a virtual machine.