Azure Front Door - multiple frontends IDs as a parameter (array) to routing rule? - azure-front-door

Question

Commonly, when there are multiple frontends IDs assigned to routing rule, they are described like this:
...
"routingRules": [
{
"name": "routingRule1",
"properties": {
"frontendEndpoints": [
{
"id": "[resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontDoorName'), 'frontendEndpoint')]"
},
{
"id": "[resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontDoorName'), 'frontendEndpoint2')]"
}
],
...
In my case I'd like to do this as a parameter type "array", but I receive error. Please see below my template, parameter file, and error message
this is front door ARM parameters deployment file
"$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"frontdoor_name": {
"value": "frontdoortest"
},
"frontends_all": {
"value": [
{
"name": "fe1",
"properties": {
"hostName": "frontdoortest.azurefd.net",
"sessionAffinityEnabledState": "Disabled",
"sessionAffinityTtlSeconds": 0,
"resourceState": "Enabled"
}
},
{
"name": "fe1customdns1",
"properties": {
"hostName": "dev.custom1.com",
"sessionAffinityEnabledState": "Enabled",
"sessionAffinityTtlSeconds": 0,
"resourceState": "Enabled"
}
},
{
"name": "fe1customdns2",
"properties": {
"hostName": "dev.custom2.com",
"sessionAffinityEnabledState": "Enabled",
"sessionAffinityTtlSeconds": 0,
"resourceState": "Enabled"
}
}
]
},
"frontends_one": {
"value": [
{
"id": "[concat(resourceId('Microsoft.Network/frontdoors', parameters('frontdoor_name')), '/FrontendEndpoints/fe1customdns1')]",
},
{
"id": "[concat(resourceId('Microsoft.Network/frontdoors', parameters('frontdoor_name')), '/FrontendEndpoints/fe1customdns2')]",
}
]
}
}
this is part of front door ARM resource deployment template
...
"parameters": {
"frontends_all": {
"type": "array"
},
"frontends_one": {
"type": "array"
},
"frontdoor_name": {
"type": "string"
}
}
...
{
"type": "Microsoft.Network/frontDoors",
"apiVersion": "2020-01-01",
"name": "[parameters('frontdoor_name')]",
"location": "Global",
"properties": {
"resourceState": "Enabled",
"frontendEndpoints": "[parameters('frontends_all')]", #### NO ERROR
"routingRules": [
{
"name": "routingRule1",
"properties": {
"frontendEndpoints": "[parameters('frontends_one')]", #### ERROR !!!
"acceptedProtocols": [
"Https"
],
"patternsToMatch": [
"/*",
],
"enabledState": "Enabled",
"resourceState": "Enabled",
"routeConfiguration": {
"#odata.type": "#Microsoft.Azure.FrontDoor.Models.FrontdoorForwardingConfiguration",
"forwardingProtocol": "MatchRequest",
"backendPool": {
"id": "[concat(resourceId('Microsoft.Network/frontdoors', parameters('frontdoor_name')), '/backendpools/test')]"
}
}
}
}
...
[error]BadRequest: Missing Hostname for FrontendEndpoint [resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontdoor_name'), 'fe1customdns2')] in RoutingRule routingRule1.,Missing Hostname for FrontendEndpoint [resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontdoor_name'), 'fe1customdns')] in RoutingRule routingRule1;
A resource reference was invalid: "[resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontdoor_name'), 'fe1customdns2')]";
A resource reference was invalid: "[resourceId('Microsoft.Network/frontDoors/frontendEndpoints', parameters('frontdoor_name'), 'fe1customdns1')]"