Genie Libs Parser

Common errors

• ModuleNotFoundError: Could not find module_name for command <command_string> for nos <os_name> from genie

  cause The Genie framework could not locate a parser module for the specified command and operating system, or the parser is named differently than expected.
  fix Verify that a parser exists for the exact command and OS (e.g., 'show ip interface brief' for 'iosxe'). You can browse the `genieparser` GitHub repository (src/genie/libs/parser) to find available parsers. If a parser does not exist, you may need to develop a custom parser. Ensure `pyats[full]` or `genie` is installed. [5 in previous search, 1]

• KeyError: 'interface' (or similar key not found in parsed output)

  cause The device's command output did not match the parser's expected structure, causing the parser to fail to extract a specific key, or the output was partially parsed.
  fix Inspect the raw CLI output and compare it against the expected schema of the parser (often found in the parser's source code or documentation). If the output deviates, the parser might need an update, or a custom parser might be required. Consider printing the raw output and the partial parsed data for debugging. [9 in previous search]

• genie.metaparser.exceptions.SchemaEmptyError: Schema has to be defined with values

  cause This error typically occurs when writing or modifying a custom parser, and the `schema` attribute within the parser's Schema class is not correctly defined or is empty.
  fix Ensure that your `Schema` class for the parser has a `schema` dictionary defined with the expected data structure. For example: `schema = { 'interface': { Any(): { 'ip_address': str }}}`. Refer to the `genie.metaparser` documentation for schema definition. [4 in previous search, 6 in previous search]

Warnings

• gotcha Parser schemas and regex patterns are highly dependent on the exact CLI output of a device. Minor changes in device OS versions or command output formatting can cause parsers to fail silently or return incomplete data.
  Fix: Always validate parsed output against expected schema, especially after device OS upgrades. Consider using Genie's 'learn' feature for baseline validation and 'diff' for change detection. If an existing parser fails, it may require a fix or a custom parser to be developed. [9 in previous search]
• breaking Direct arguments like 'username', 'enable_password' for Unicon (a core pyATS connection library) have been deprecated and replaced by a 'credentials' dictionary.
  Fix: Update connection configurations to use the `credentials` dictionary within your testbed YAML or device object, e.g., `device.credentials.default.username = 'admin'`. [5 in previous search]
• gotcha When running pyATS/Genie with Nornir using multiple workers, issues have been reported where Genie processing can fail.
  Fix: If encountering parsing issues with Nornir multi-worker setups, consider collecting output with Nornir and then processing it with Genie in a single-threaded manner, or limit Nornir's worker count to 1 for parser-intensive tasks. [18 in previous search]
• gotcha Some parser modules might contain syntax errors, particularly in older or custom parsers, leading to `SyntaxError` exceptions during execution.
  Fix: Check the traceback for the specific parser file and line number. If it's a built-in parser, ensure your `genie-libs-parser` package is up to date. If it's a custom parser, review the Python syntax. [15 in previous search]

Install

• pip install pyats[full] Recommended for full Genie/pyATS functionality
• pip install genie Installs Genie and its components, including parsers

Imports

• device.parse

  from pyats.topology import loader
  # ... load testbed and device
  output = device.parse('show version')

  This is the primary and recommended way to use the parsers, leveraging the pyATS device object.
• ShowVersion
  wrong:

  from genie.libs.parser.show_version import ShowVersion

  correct:

  from genie.libs.parser.iosxe.show_version import ShowVersion
  # ... create device object
  parser = ShowVersion(device=device_object)
  parsed_output = parser.parse()

  Parser classes are located within OS-specific submodules (e.g., `iosxe`, `nxos`). Direct instantiation is less common than `device.parse()` for general usage.

Quickstart

This quickstart demonstrates how to use `genie-libs-parser` to parse device CLI output into a structured dictionary. It shows both the recommended `device.parse()` method (simulating output for offline use) and direct instantiation of a parser class. A dummy `Device` object is created to provide the necessary context for the parsers. In a live environment, the `device` object would be loaded from a pyATS testbed and connected to a physical or virtual device. [8 in previous search, 1]

import os
from pyats.topology import Device
from genie.libs.parser.iosxe.show_version import ShowVersion

# Simulate a device object for demonstration (in a real scenario, use pyats.topology.loader)
device = Device(name='my_router', os='iosxe')
# This is a hack to allow parsing without an active connection, typically used for offline parsing
device.custom.setdefault('abstraction', {})['order'] = ['os', 'platform']

# Simulate CLI output
cli_output = '''
Cisco IOS XE Software, Version 17.03.04a
Cisco IOS Software [Dublin], ISR Software (X86_64_LINUX_IOSD_UNIVERSALK9-VIRT_STD_ML), Version 17.3.4a, RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2021 by Cisco Systems, Inc.
Compiled Wed 21-Apr-21 02:40 by mcpre

ROM: System Bootstrap, Version 17.3.1R

my_router uptime is 1 week, 2 days, 3 hours, 4 minutes
System returned to ROM by reload
System image file is "bootflash:isr4400-universalk9.17.03.04a.SPA.bin"
Last reload reason: PowerSupplyFailure
'''

# --- Option 1: Using device.parse() (recommended) ---
# In a real scenario, device.parse() would execute the command on the device.
# For offline parsing, you can pass the 'output' argument.
parsed_data_via_device = device.parse('show version', output=cli_output)
print("Parsed data via device.parse():\n", parsed_data_via_device)

# --- Option 2: Directly instantiating a parser class (less common for general use) ---
parser = ShowVersion(device=device) # The device object provides context (OS, etc.)
parsed_data_via_class = parser.parse(output=cli_output)
print("\nParsed data via direct class instantiation:\n", parsed_data_via_class)