How to reference an object in an array of objects using Bicep - azure

Question

I am trying to output the referenceId of each subnet in a module that creates a virtual network with 4 subnets. I can get the first one, [0], but when I try output the others, [1], [2], [3] the deployment fails and throws the error:
The language expression property array index "1" is out of bounds
Below is the code to create the virtualNetwork and the subnets:
resource virtualNetwork 'Microsoft.Network/virtualNetworks#2018-11-01' = {
name: vNetName
location: location
tags: tags
properties: {
addressSpace: {
addressPrefixes: [
addressPrefix
]
}
subnets: subnets
}
}
subnets is a variable of type array:
var subnets = [
{
name: mgmtSubnetName
properties: {
addressPrefix: mgmtSubnetAddressPrefix
}
}
{
name: intSubnetName
properties: {
addressPrefix: intSubnetAddressPrefix
}
}
{
name: extSubnetName
properties: {
addressPrefix: extSubnetAddressPrefix
}
}
{
name: vdmsSubnetName
properties: {
addressPrefix: vdmsSubnetAddressPrefix
}
}
]
When I use the output line below, it returns and array that has 4 objects...one for each subnet created:
output subnets array = virtualNetwork.properties.subnets
Each object has the format below:
{
"name":"<value>",
"id":"<value>",
"etag":"<value>",
"properties":{
"provisioningState":"Succeeded",
"addressPrefix":"<value>",
"ipConfigurations":[
{
"id":"<value>"
}
],
"delegations":[]
},
"type":"Microsoft.Network/virtualNetworks/subnets"
}
When I use the output line below, it returns the first object in the subnets array:
output subnet1 object = virtualNetwork.properties.subnets[0]
When I use the output line below, it returns the resourceId of the first subnet:
output subnet1 string = virtualNetwork.properties.subnets[0].id
I am unable to retrieve the other objects in the array using indexes 1, 2, or 3.
I have also tried the resourceId function (example below) but the behavior is exactly the same for indexes 1, 2, or 3:
output subnet1Id string = resourceId('Microsoft.Network/VirtualNetworks/subnets', name, subnets[0].name)

Answer 1

You can use the below bicep template to deploy the vnet and subnets and output the subnets and subnet id's like below :
var subnets = [
{
name: 'vm-subnet'
properties: {
addressPrefix:'10.0.0.0/24'
}
}
{
name: 'webapp-subnet'
properties: {
addressPrefix:'10.0.1.0/24'
}
}
{
name: 'appgw-subnet'
properties: {
addressPrefix:'10.0.2.0/24'
}
}
{
name: 'bastion-subnet'
properties: {
addressPrefix:'10.0.3.0/24'
}
}
]
resource virtualNetwork 'Microsoft.Network/virtualNetworks#2018-11-01' = {
name: 'ansuman-vnet'
location: 'east us'
properties: {
addressSpace: {
addressPrefixes: [
'10.0.0.0/16'
]
}
subnets: subnets
}
}
output subnets array = [for (name, i) in subnets :{
subnets : virtualNetwork.properties.subnets[i]
}]
output subnetids array = [for (name, i) in subnets :{
subnets : virtualNetwork.properties.subnets[i].id
}]
output subnetappgw string = virtualNetwork.properties.subnets[2].id
output webappsubnet object = virtualNetwork.properties.subnets[1]
Outputs:
Note: I am using the latest Bicep version i.e. Bicep CLI version 0.4.1124