IaC Lab01 build dynamic inventory from VM launch traces

build_lab_inventory.py

#!/usr/bin/env python3

import os
import re
import sys

import yaml

"""
VM launch trace file
. The .txt file is generated by ovs-startup.sh script with color ANSI code
. The .save file is text only
"""
basename = "launch_output"
traceFile = "trace/" + basename + ".txt"
clean_traceFile = "trace/" + basename + ".save"

GROUPNAME = "vms"
VM_PATTERN = "Virtual machine filename"
ADDRESS_PATTERN = "IPv6 LL address"

if not os.path.isfile(traceFile):
    print("Virtual machines launch trace file does not exist.", file=sys.stderr)
    print("Are the virtual machines running ?", file=sys.stderr)
    sys.exit(1)

if os.path.isfile(clean_traceFile):
    os.remove(clean_traceFile)

print("Generate trace file with no ANSI codes.")
ansi_escape = re.compile(r"\x9B|\x1B[)[0-?]*[ -/]*[@-~]")
with open(traceFile, "r") as src:
    with open(clean_traceFile, "w") as dst:
        for line in src:
            ansi_escape.sub("", line)
            dst.write(ansi_escape.sub("", line))

"""
Virtual machine inventory generation
Virtual machine name and IPv6 link local addresses are extracted from trace file
"""
data = {
    GROUPNAME: {
        "hosts": {},
        "vars": {
            "ansible_ssh_user": "{{ vm_user }}",
            "ansible_ssh_pass": "{{ vm_pass }}",
            "ansible_become": "true",
            "ansible_become_password": "{{ vm_pass }}",
        },
    }
}

with open(clean_traceFile, "r") as src:
    lines = src.readlines()  # List all the lines of trace file

    vm_name_found = False  # Router name has not been found yet
    vm_address_found = False  # Router address has not been found yet
    for line in lines:
        if not vm_name_found:
            vm_name = ""
        if not vm_address_found:
            vm_address = ""
        line = line.strip()  # Remove leading/trailing white spaces
        if re.search(VM_PATTERN, line) and not vm_name_found:
            line = line.split(":")[1]  # Get all characters after ':'
            line = line.strip()
            line = line.split(".")[0]  # Strip file extension
            vm_name = line
            vm_name_found = True
        elif (
            re.search(ADDRESS_PATTERN, line) and vm_name_found and not vm_address_found
        ):
            line = line.split(" :")[1]  # Get all characters after ':'
            line = line.strip()
            line = line.split("%")[0]  # Strip interface name from address
            vm_address = f'{line + "%enp0s1"}'  # Add new interface name
            vm_address_found = True

        if vm_name_found and vm_address_found:  # New inventory entry
            vm_data = {vm_name: {"ansible_host": vm_address, "ansible_port": 2222}}

            data["vms"]["hosts"].update(vm_data)  # Add new entry to inventory
            vm_name_found = False  # Get ready to look for another virtual machine
            vm_address_found = False

# yaml_output = yaml.dump(data, sort_keys=False)
# print(yaml_output) # New inventory

"""
Write results to inventory file
"""
inventoryFile = "inventory/lab.yml"

with open(inventoryFile, "w") as dst:
    yaml.dump(data, dst, sort_keys=False)