Arm Templates Copy Function - Skip Properties in loop if not present - Network Security Group - sourceAddressPrefix/sourceAddressPrefixes - arrays

Question

I am trying to implement a copy function in a arm template used to deploy Network security group.
I have previously deployed templates using this format but due to Microsoft deciding to use two distinct names depending on if the Property is a single item or a list I am unable to use the copy function.
I have had to look into using If statements to ignore null parameters if present in a loop, which I have not been able to achieve.
So my question is how to go through a loop and ignore a specific Property if it not present in a loop.
The two Properties in question are
sourceAddressPrefix or sourceAddressPrefixes.
This is causing problems in the 2nd interation, I will get an error message
The
language expression property 'sourceAddressPrefixes' doesn't exist (if i switch the order of the paramater file, ie sourceAddressPrefixes is first, then the error message will point to 'sourceAddressPrefix'
Parameter file,
as you can see there are two secutiry rules, one set as sourceAddressPrefix, and the other sourceAddressPrefixes
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"location": {
"value": "westeurope"
},
"SecurityRule":{
"value": [
{
"name": "AllowSyncWithAzureAD",
"protocol": "Tcp",
"sourcePortRange": "*",
"destinationPortRange": "443",
"sourceAddressPrefix": "*",
"destinationAddressPrefix": "*",
"access": "Allow",
"priority": 101,
"direction": "Inbound"
},
{
"name": "AllowPSRemotingSliceP",
"protocol": "Tcp",
"sourcePortRange": "*",
"destinationPortRange": "5986",
"sourceAddressPrefixes": "[variables('PSRemotingSlicePIPAddresses')]",
"destinationAddressPrefix": "*",
"access": "Allow",
"priority": 301,
"direction": "Inbound"
}
]
}
}
}
in the Template file I have added both properties with if statements, but clearly I have not written them correctly, as the intended outcome is, if in a loop the property does not exist, ignore property.
{
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"location": {
"type": "string",
"defaultValue": "[resourceGroup().location]",
"metadata": {
"description": "Location for all resources."
}
},
"SecurityRule": {
"type": "array"
}
},
"variables": {
"domainServicesNSGName": "AGR01MP-NSGAADDS01",
"PSRemotingSlicePIPAddresses": [
"52.182.100.238",
"52.180.177.87"
],
"RDPIPAddresses": [
"210.66.188.40/27",
"15.156.75.52/27",
"134.104.124.36/27",
"144.122.4.96/27"
],
"PSRemotingSliceTIPAddresses": [
"56.180.182.67",
"56.180.121.39",
"56.175.228.121"
]
},
"resources": [
{
"apiVersion": "2018-10-01",
"type": "Microsoft.Network/networkSecurityGroups",
"name": "[variables('domainServicesNSGName')]",
"location": "[parameters('location')]",
"properties": {
"copy": [
{
"name":"securityRules",
"count": "[length(parameters('securityRule'))]",
"mode": "serial",
"input": {
"name": "[concat(parameters('securityRule')[copyIndex('securityRules')].name)]",
"properties": {
"protocol": "[concat(parameters('securityRule')[copyIndex('securityRules')].protocol)]",
"sourcePortRange": "[concat(parameters('securityRule')[copyIndex('securityRules')].sourcePortRange)]",
"destinationPortRange": "[concat(parameters('securityRule')[copyIndex('securityRules')].destinationPortRange)]",
"sourceAddressPrefixes": "[if(equals(parameters('securityRule')[copyIndex('securityRules')].sourceAddressPrefixes,''), json('null'), parameters('securityRule')[copyIndex('securityRules')].sourceAddressPrefixes)]",
"sourceAddressPrefix": "[if(equals(parameters('securityRule')[copyIndex('securityRules')].sourceAddressPrefix,''), json('null'), parameters('securityRule')[copyIndex('securityRules')].sourceAddressPrefix)]",
"destinationAddressPrefix": "[concat(parameters('securityRule')[copyIndex('securityRules')].destinationAddressPrefix)]",
"access": "[concat(parameters('securityRule')[copyIndex('securityRules')].access)]",
"priority": "[concat(parameters('securityRule')[copyIndex('securityRules')].priority)]",
"direction": "[concat(parameters('securityRule')[copyIndex('securityRules')].direction)]"
}
}
}
]
}
}
],
"outputs": {}
}

Answer 1

found solution
"sourceAddressPrefix": "[if(equals(parameters('SecurityRule')[copyIndex('securityRules')].name, 'SyncWithAzureAD'), parameters('SecurityRule')[copyIndex('securityRules')].sourceAddressPrefix, json('null'))]" ,
"sourceAddressPrefixes": "[if(contains(parameters('SecurityRule')[copyIndex('securityRules')].name, 'Allow'), parameters('SecurityRule')[copyIndex('securityRules')].sourceAddressPrefixes, json('null'))]" ,
the above code allows me to deploy to change to ignore a null value in an array. Though I had to change AllowSyncWithAzureAD to SyncWithAzureAD, in order for it not to be picked up by the 2nd line