Technical Documentation: read_testinfra.py

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Overview

The read_testinfra.py module is responsible for modeling and validating the structure of a network infrastructure, including:

• Definitions of networks and machines
• Validation of IP addressing (IPv4/IPv6)
• Loading configuration from a .yml file
• Ensuring consistency and existence of referenced resources (e.g., NFTable files)

This module is designed for use in network testbed setups where configuration integrity and address validation are critical.

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Exception Handling

• ValueError: Raised indirectly when an invalid IP address format is provided to ipaddress.ip_address.
• AttributeError:
  • When IPv4 and IPv6 addresses are mixed within a machine.
  • When required fields (Networks, Machines, or at least one valid NFTable file) are missing from the YAML configuration.

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Module Structure

class Machine

Represents a network-connected machine.

__init__(self, name: str, ip_addresses: list, management_ip: str, username: str, password: str, nftable: str)

Initializes a Machine object with network and authentication parameters.

• Parameters:

  • name (str): Identifier for the machine.
  • ip_addresses (list): List of IP addresses (must be all IPv4 or all IPv6).
  • management_ip (str): IP used for management access.
  • username / password (str): Credentials for remote login.
  • nftable (str): Optional path to the machine’s NFTable file.

• Validation:

  • All ip_addresses must be of the same IP version (IPv4 or IPv6).
  • Raises AttributeError on mixed IP version input.

• Attributes:

  • name
  • ip_addresses (List of IPv4Address or IPv6Address)
  • management_ip (ipaddress object)
  • user, password
  • nftable

__eq__(self, other)

Checks object equality by comparing name, ip_addresses, and management_ip.

__repr__(self)

Returns a string representation including name, IPs, and management IP.

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class NetworkConfiguration

Represents the overall network configuration, including all networks and machines.

__init__(self)

Initializes empty dictionaries for networks and machines.

• Attributes:
  • networks (dict): Mapping of network names to ip_network objects.
  • machines (dict): Mapping of machine names to Machine objects.

add_networks(self, name, netmask, netaddress)

Adds a new network to the configuration.

• Parameters:

  • name (str): Network identifier.
  • netmask (str or int): Subnet mask.
  • netaddress (str): Network address.

• Result:

  • Updates self.networks with a new ip_network object.

add_machine(self, name, ip_address, management_ip, username, password, nftable)

Adds a machine entry to the configuration.

• Parameters: Same as Machine.__init__.

• Result:

  • Adds a Machine instance to self.machines.

__eq__(self, other)

Compares the networks and machines dictionaries for equality.

__repr__(self)

Returns a string showing all stored networks and machines.

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load_from_yaml(self, file_name)

Loads a YAML configuration file and populates the network and machine objects.

• Parameters:

  • file_name (str): Path to the YAML file describing the infrastructure.

• Expected YAML Structure:

Networks:
  net1:
    Netmask: 255.255.255.0
    Netaddress: 192.168.1.0

Machines:
  host1:
    IP: [192.168.1.10]
    Management: 192.168.1.1
    User: admin
    Password: admin123
    NFTable: ./firewall.nft