Update SQL Server Firewall Rule Using Powershell

UpdateAzureFirewallRule.ps1

param 
([Parameter(Mandatory)][string]$resourceGroupName, 
[Parameter(Mandatory)][string]$sqlServerName,
[Parameter(Mandatory)][string]$ruleName) 
<#
TODO:
 - Add option to create firewall rule if it doesn't exist already
 - Wrap wxternal method calls in try/catch blocks
 - Add option to use PC name as rule name. Reduces the number of params that need to be provided
 - Improve log messages
 #>

#Get-ComputerInfo | Select -Property CsUSerName

echo "Getting public IP address"
$ip = Invoke-RestMethod http://ipinfo.io/json | Select -exp ip
#Had to wrap ConvertFromJson in parenthesis, see here: https://stackoverflow.com/questions/55500059/read-multiple-json-files-into-an-array-of-powershell-objects-and-filter-out-thos
#COuld hav for-eached or reassigned va but didn't want to

echo "Getting existing firewall rules"
#Specity the variable as an array type to simplify checking the result. If a single result is returned from Where-Object we get an object, if > 1 results we get an array.
#By declaring the var as an array now, no matter the results returned we simplify the comparison later
[array]$rules = (az sql server firewall-rule list -g $resourceGroupName -s $sqlServerName | ConvertFrom-Json) | Where-Object { $_.name -eq $ruleName }

#Need a check if result is null - have to create
#If result greater than 1 > exception
if ($rules.Count -ne 1) {
throw "Too many rules returned. Check the search string"} 

#update rule
echo "Updating existing firewall rule"
$result = az sql server firewall-rule update -g $resourceGroupName -s $sqlServerName -n $rules[0].name --start-ip-address $ip --end-ip-address $ip
echo $result