Libvirt interactive script to add dhcp static host on managed networks

libvirt-add-dhcp-host.sh

#!/bin/bash

set -u

COLOR_RED='\e[31m'
COLOR_GREEN='\e[31m'
RESET_FONT='\e[0m'

function printError() {
	echo -e "${COLOR_RED}${1}${RESET_FONT}"
}

networks_raw=$(virsh net-list --all | tail -n +3 | awk '{print $1}')
netidx=0
declare -a networks
for net in $networks_raw; do
	echo "$netidx"') '"$net"
	networks[$netidx]="$net"
	netidx=$(($netidx+1))
done

unset net
unset networks_raw

while true; do
	read -r -p 'Which network? ' answer
	[[ "$answer" =~ ^[0-9]+$ ]] && [ $((answer)) -lt $netidx ] && break
	printError 'Wrong input, please type in one of the above networks index'
done
networkName="${networks[$((answer))]}"
echo "You selected ${networkName}"

unset netidx
unset networks
unset answer

# networkName: user selected network name

inDhcpBlock=false
virsh net-dumpxml "$networkName" | while IFS= read -r line; do
	if [[ "$line" =~ '<dhcp>' ]]; then
		inDhcpBlock=true
		continue
	fi
	if [[ "$line" =~ '</dhcp>' ]]; then
		break
	fi
	$inDhcpBlock && echo "$line"
done
unset line
unset inDhcpBlock

while true; do
	while true; do
		read -r -p 'Mac address? ' macAddress
		[[ "$macAddress" =~ ^([0-9a-fA-F]{2}:){5}[0-9a-fA-F]{2}$ ]] && break
		printError 'Invalid mac address'
	done
	while true; do
		read -r -p 'IP address? ' ipAddress
		[[ "$ipAddress" =~ ^([0-9]{1,3}\.){3}[0-9]{1,3}$ ]] && break
		printError 'Invalid ip address'
	done
	read -r -p 'Hostname? ' hostName
	entry="<host mac='${macAddress}' name='${hostName}' ip='${ipAddress}'/>"
	echo 'About to insert following entry:'
	echo "$entry"
	while true; do
		read -r -p 'Accept? [Y/n]' answer
		[[ ("$answer" = 'n') || ("$answer" = 'N') ]] && break
		[[ (-z "$answer") || ("$answer" = 'y') || ("$answer" = 'Y') ]] && break 2
		printError 'Invalid answer, please input "y" or "n"'
	done
done

virsh net-update "$networkName" add-last ip-dhcp-host "$entry" --config --live