Help Understanding filter

[davama]

Hello,

Im currently playing around with nornir. It's pretty amazing!! Thank you for this project!!

Currently, nornir is pulling inventory from netbox from X region without issue.

    inventory={ ...
            "filter_parameters": {
                "region": "bla"
            }
...

Im able to do the following filters and they work fine: 👍

devices = nr.filter(name=device_input) 
devices = nr.filter(platform="ios")
devices = nr.filter(oxidized="usa-wkl_agg")  # this is a custom field
devices = nr.filter(serial="bla")
devices = nr.filter(hostname="xx:xx:xx:36")
devices = nr.filter(F(platform__eq="ios"))

Im having trouble with filtering with other fields. For example site and type and role . So I probably don't fully understand how filtering work... 👎

devices = nr.filter(model="c6880x")
devices = nr.filter(site="usa-ht")
devices = nr.filter(manufacturer="cisco")
devices = nr.filter(role="agg")
devices = nr.filter(F(site__eq="usa-ht"))

This is how one of my objects looks like when I do print(json.dumps(nr.inventory.hosts['rtr-36'].dict()))

{
  "name": "rtr-36",
  "connection_options": {},
  "groups": [
    "site__usa-wkl",
    "platform__ios",
    "device_role__agg",
    "manufacturer__cisco",
    "device_type__c6880x"
  ],
  "data": {
    "id": 486,
    "url": "https://netbox.example.com/api/dcim/devices/486/",
    "display": "rtr-36",
    "name": "rtr-36",
    "device_type": {
      "id": 36,
      "url": "https://netbox.example.com/api/dcim/device-types/36/",
      "display": "c6880x",
      "manufacturer": {
        "id": 1,
        "url": "https://netbox.example.com/api/dcim/manufacturers/1/",
        "display": "Cisco",
        "name": "Cisco",
        "slug": "cisco"
      },
      "model": "c6880x",
      "slug": "c6880x"
    },
    "device_role": {
      "id": 2,
      "url": "https://netbox.example.com/api/dcim/device-roles/2/",
      "display": "Agg",
      "name": "Agg",
      "slug": "agg"
    },
    "tenant": null,
    "platform": {
      "id": 1,
      "url": "https://netbox.example.com/api/dcim/platforms/1/",
      "display": "ios",
      "name": "ios",
      "slug": "ios"
    },
    "serial": "my-sn",
    "asset_tag": null,
    "site": {
      "id": 3,
      "url": "https://netbox.example.com/api/dcim/sites/3/",
      "display": "USA-WKL",
      "name": "USA-WKL",
      "slug": "usa-wkl"
    },
    "location": null,
    "rack": null,
    "position": null,
    "face": null,
    "parent_device": null,
    "status": {
      "value": "active",
      "label": "Active"
    },
    "airflow": null,
    "primary_ip": {
      "id": 1375,
      "url": "https://netbox.example.com/api/ipam/ip-addresses/1375/",
      "display": "xxx:xxx::36/128",
      "family": 6,
      "address": "xxx:xxx::36/128"
    },
    "primary_ip4": {
      "id": 501,
      "url": "https://netbox.example.com/api/ipam/ip-addresses/501/",
      "display": "x.x.x.36/32",
      "family": 4,
      "address": "x.x.x.36/32"
    },
    "primary_ip6": {
      "id": 1375,
      "url": "https://netbox.example.com/api/ipam/ip-addresses/1375/",
      "display": "xxx:xxx::36/128",
      "family": 6,
      "address": "xxx:xxx::36/128"
    },
    "cluster": null,
    "virtual_chassis": null,
    "vc_position": null,
    "vc_priority": null,
    "comments": "",
    "local_context_data": null,
    "tags": [],
    "config_context": {
      "device_web": {
        "ipv4": "x.x.x.x",
        "ipv6": "xx:xx:xx",
        "name": "hostname"
      },
      "ntp_servers": [
        "xx:xx:xx"
      ],
      "device_inmon": {
        "ipv4": "x.x.x.x",
        "ipv6": "xx:xxx:xx",
        "name": "hostname"
      },
      "device_region": "USA",
      "syslog_servers": [
          "xxxx:xxx:x"
      ],
      "management_info": {
        "radius_ipv4": [
          "x.x.x.x",
          "x.x.x.x",
          "x.x.x.x",
          "x.x.x.x"
        ],
        "radius_ipv6": [
          "xxxx:xxx:x",
          "xxxx:xxx:x",
          "xxxx:xxx:x",
          "xxxx:xxx:x"
        ],
        "radius_name": [
          "radius1",
          "radius2",
          "radius3",
          "radius4"
        ]
      }
    },
    "created": "2021-11-15",
    "last_updated": "2022-02-25T18:41:50.809743Z",
    "oxidized": "usa-wkl_agg"
  },
  "hostname": "xxx:xxx::36",
  "port": null,
  "username": null,
  "password": null,
  "platform": "ios"
}

Yes, I've looked at https://nornir.readthedocs.io/en/latest/tutorial/inventory.html?highlight=filter#Filter-functions but still need some clarification 😞

Any input is appreciated!

Thank you,
Dave

[dbarrosop]

The filters that are not working are because you are not following your data model. For instance, you write:

devices = nr.filter(model="c6880x")

but there is no model field in your data, you have however device_type["model"] = "c6880x" so what you probably want is something like:

devices = nr.filter(F(device_type__model="c6880x"))

Rest of the fields have similar issues, for instance, I think you want:

devices = nr.filter(F(site__name="usa-ht"))
devices = nr.filter(F(device_type__manufacturer__slug="cisco"))
...

Look at the examples at the bottom here, the ones using nested_data, as that's pretty much what you want.

[dbarrosop]

And by the way, you don't need __eq using the F object as it is implicit, so devices = nr.filter(F(platform__eq="ios")) and devices = nr.filter(F(platform="ios")) are basically equivalent (just FYI, you are free to leave it if you feel it is more readable, both are technically correct)

[davama]

@dbarrosop
This was very insightful.
Thank you very much