Assertions

Assertions define expected network state in YAML format.

Basic structure

assertions:
  - target: device:port
    path: path/to/leaf
    expect: expected_value

Short path syntax

netsert uses a short path syntax that expands to full OpenConfig paths:

Short path	Expands to
interfaces[Ethernet1]/state/oper-status	/interfaces/interface[name=Ethernet1]/state/oper-status
bgp[default]/neighbors[10.0.0.1]/state/session-state	/network-instances/network-instance[name=default]/protocols/protocol[identifier=BGP][name=BGP]/bgp/neighbors/neighbor[neighbor-address=10.0.0.1]/state/session-state
system/state/hostname	/system/state/hostname

Rule: Leading / = full path (passthrough). No leading / = short path (expanded).

Targeting devices

Single device

assertions:
  - target: spine1.example.com:6030
    path: interfaces[Ethernet1]/state/oper-status
    expect: UP

Multiple devices (inline)

assertions:
  - target:
      - spine1:6030
      - spine2:6030
    path: interfaces[Ethernet1]/state/oper-status
    expect: UP

Inventory groups

Define groups in your config file, then reference them with @:

netsert.yaml

inventory:
  groups:
    spines:
      - spine1:6030
      - spine2:6030
    leaves:
      - leaf1:6030
      - leaf2:6030

assertions.yaml

assertions:
  - target: "@spines"
    path: interfaces[Ethernet1]/state/oper-status
    expect: UP

Comparison operators

Operator	Usage	Example
equals	Exact match (default)	expect: UP
contains	Substring match	expect: "contains:Ethernet"
regex	Regular expression	expect: "regex:^4\\.2[89]\\."
exists	Path exists	expect: exists
not_exists	Path doesn’t exist	expect: not_exists
>	Greater than	expect: ">100"
<	Less than	expect: "<500"

Examples

Interface status

assertions:
  - target: "@all"
    path: interfaces[Ethernet1]/state/oper-status
    expect: UP

BGP sessions

assertions:
  - target: "@leaves"
    path: bgp[default]/neighbors[10.0.0.1]/state/session-state
    expect: ESTABLISHED

OSPF neighbors

assertions:
  - target: "@core"
    path: ospf[default][0]/neighbors[10.0.0.2]/state/adjacency-state
    expect: FULL

System info with regex

assertions:
  - target: "@all"
    path: system/state/software-version
    expect: "regex:^4\\.2[89]\\."