textfsm_parser

The textfsm_parser module is based on Google TextFSM definitions. This module iterates over matching rules defined in TextFSM format, extracts data from structured ASCII text based on those rules, and returns Ansible facts in a JSON data structure that can be added to inventory host facts and/or consumed by Ansible tasks and templates.

The textfsm_parser module requires two inputs:

the output of commands run on the network device, passed to the content parameter
the parser template that defines the rules for parsing the output, passed to either the file or the src parameter

content

The content parameter for textfsm_parser must point to the ASCII text output of commands run on network devices. The text output can be in a variable or in a file.

file

The file parameter for textfsm_parser must point to a parser template that contains a TextFSM rule for each data field you want to extract from your network devices.

Parser templates for the textfsm_parser module in the Network Engine role use TextFSM notation.

name

The name parameter for textfsm_parser names the variable in which Ansible will store the JSON data structure. If name is not set, the JSON facts from parsing will not be displayed/exported.

src

The src parameter for textfsm_parser loads your parser template from an external source, usually a URL.

Sample Parser Templates

Here is a sample TextFSM parser template:

parser_templates/ios/show_interfaces


Value Required name (\S+)
Value type ([\w ]+)
Value description (.*)
Value mtu (\d+)

Start
  ^${name} is up
  ^\s+Hardware is ${type} -> Continue
  ^\s+Description: ${description}
  ^\s+MTU ${mtu} bytes, -> Record

Sample Playbooks

To extract the data defined in your parser template, create a playbook that includes the Network Engine role and references the content and file parameters of the command_parser module.

The example playbook below runs a show command, imports the Network Engine role, extracts data from the text output of the command by matching it against the rules defined in your parser template, and stores the results in a variable. To view the content of that final variable, add it to the name parameter as shown in the example and run the playbook in verbose mode: ansible-playbook -v.

Make sure the hosts definition in the playbook matches a host group in your inventory - in these examples, the playbook expects a group called ios.

The example below parses the output of the show interfaces command on IOS and creates facts from that output:


---

# ~/my-playbooks/textfsm-gather-interface-info.yml

- hosts: ios
  connection: network_cli

  tasks:
  - name: Collect interface information from device
    ios_command:
      commands: "show interfaces"
    register: ios_interface_output

  - name: Generate interface facts as JSON
    textfsm_parser:
      file: "parser_templates/ios/show_interfaces"
      content: "{{ ios_interface_output.stdout.0 }}"
      name: interface_facts

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