Getting structured output from show commands using Netpicker and TextFSM

When using show commands in a Netpicker Python rule, the output of these show commands will be plain text, like in this rule:

medium(
    name='rule_fsm_example',
    platform=['cisco_ios'],
    commands=dict(arp='show ip arp')
)
def rule_fsm_example(commands):
    print(commmands.arp)

Which will give this plain text output:

show ip arp:
Protocol  Address          Age (min)  Hardware Addr   Type   Interface
Internet  192.168.60.2          117   000c.292e.36b6  ARPA   Ethernet0/3
Internet  192.168.60.3            8   000c.2962.ba5e  ARPA   Ethernet0/3
Internet  192.168.60.32          15   000c.2987.5096  ARPA   Ethernet0/3
Internet  192.168.60.128          2   000c.2939.45ea  ARPA   Ethernet0/3
Internet  192.168.60.201          -   aabb.cc02.f030  ARPA   Ethernet0/3

But did you know that Netpicker can automatically parse this text using TextFSM? You just have to add the .fsm suffix:

medium(
    name='rule_fsm_example',
    platform=['cisco_ios'],
    commands=dict(arp='show ip arp')
)
def rulefsm_examplecommands):
    print(commands.arp.fsm)

Which will output:

[
   {
      "protocol":"Internet",
      "ip_address":"192.168.60.2",
      "age":"117",
      "mac_address":"000c.292e.36b6",
      "type":"ARPA",
      "interface":"Ethernet0/3"
   },
   {
      "protocol":"Internet",
      "ip_address":"192.168.60.3",
      "age":"8",
      "mac_address":"000c.2962.ba5e",
      "type":"ARPA",
      "interface":"Ethernet0/3"
   },
   ...
]

Netpicker uses the Network to Code NTC Templates library for the parsing. So if the command you want to parse isn’t there yet, feel free to contribute to their repository.

P.S. Did you know that you can parse the real-time command output as well, using device.cli('show ip arp').fsm?