Command Parsers Datasource¶

This datasource provides custom TextFSM and TTP parser templates that the app uses at runtime to parse CLI command output. This is useful when:

You need a custom parser not available in ntc-templates
You want to override an existing ntc-templates parser with a custom version
You are using TTP templates (which are not included in ntc-templates)

Directory Structure¶

repository_root/
├── parsers/
│   ├── cisco_ios/
│   │   ├── show_version.textfsm
│   │   ├── show_ip_bgp_summary.textfsm
│   │   └── show_interfaces.ttp
│   ├── arista_eos/
│   │   ├── show_version.textfsm
│   │   └── show_ip_bgp_summary.ttp
│   └── juniper_junos/
│       └── show_bgp_summary.ttp

File Naming Convention¶

The app converts the CLI command to a filename by replacing spaces with underscores:

CLI Command	Expected Filename
`show version`	`show_version.textfsm` or `show_version.ttp`
`show ip bgp summary`	`show_ip_bgp_summary.textfsm` or `show_ip_bgp_summary.ttp`
`show interfaces`	`show_interfaces.textfsm` or `show_interfaces.ttp`

The file extension (.textfsm or .ttp) must match the parser type configured on the CommandParser object.

Parser File Path Resolution¶

At runtime, the app resolves parser file paths using a Jinja2 template. The default template renders to a path like cisco_ios/show_version, which is then appended to the parsers/ directory in the Git repository and given the appropriate file extension.

The full resolution path is: <repo>/parsers/<network_driver>/<command_filename>.<parser_type>

Example: For a device with platform cisco_ios running show ip bgp summary with a textfsm parser:

<repo>/parsers/cisco_ios/show_ip_bgp_summary.textfsm

Customizing the Path Template¶

The path template can be customized via the GIT_PARSERS_PATH setting in your Nautobot configuration or via the Constance admin UI. Available template variables:

Variable	Description
`{{ obj }}`	The device object
`{{ obj.platform.network_driver }}`	The platform's network driver (e.g., `cisco_ios`)
`{{ cmd }}`	The command converted to a filename (spaces replaced with underscores)

Parser Lookup Behavior¶

When the app needs to parse command output, it follows this lookup order:

Parser Type	Custom Git Template	Fallback
TextFSM	Checks Git repos for `.textfsm` file	Falls back to ntc-templates built-in templates
TTP	Checks Git repos for `.ttp` file	No fallback — fails if not found in a Git repo
NAPALM	N/A	Uses NAPALM getter directly
JSON	N/A	Parses JSON output directly

Warning

TTP parsers must be provided through a Git repository. There is no built-in fallback for TTP templates. If a TTP template is not found, the command output parsing will fail.