Is it possible to find a specific element in an array using BICEP and a substring of the name?

Problem

StorageAccounts.bicep is a bicep module that creates numerous storage accounts and outputs an array of their names:

@description('Name of Environment')
param environment string

param storageAccounts array = [
  {
    name : 'api${environment}${uniqueString(resourceGroup().id)}'
    skuName : 'Standard_LRS'
    accessTier : 'Hot'
  }
  {
    name : 'web${environment}${uniqueString(resourceGroup().id)}'
    skuName : 'Standard_LRS'
    accessTier : 'Hot'
  }
]

resource storage_resource 'Microsoft.Storage/storageAccounts@2021-06-01' = [for storage in storageAccounts: {
  name : storage.name
  location : resourceGroup().location
  sku:{
    name : storage.skuName
  }
  kind : 'StorageV2'
  properties:{
    accessTier: storage.accessTier
    allowBlobPublicAccess: true
    minimumTlsVersion: 'TLS1_2'
    supportsHttpsTrafficOnly: true
    encryption:{
      keySource: 'Microsoft.Storage'
      services:{
        blob:{
          keyType: 'Account'
          enabled: true
        }
        file:{
          keyType: 'Account'
          enabled: true
        }
      }
    }    
  }
}]

output storageAccounts array = [for (name, i) in storageAccounts:{
    storageAccountName : name
}]

I’m giving that array to another module to make a function app, and I’m looking for a specific item in the array, like this:

@description('array of storage account names')
param storageAccounts array

var storageAccountName = storagesAccounts.where(function(storageAccount) {
  return storageAccount.name.startsWith('api')
})


resource storageAccount 'Microsoft.Storage/storageAccounts@2019-04-01' existing = {
  name: storageAccountName
}

Is this something I’m capable of doing? Is it better to create the storage accounts individually and send the name to them directly?

Asked by John McArthur

Solution #1

Currently its not supported to find the element of an array in bicep . There are Github Issues on the same Issue 1 and Issue 2 .

As a workaround you can just pass the storage account which you need to the module and use it then in the module i.e. nested template.

I tried the following to create two storage accounts, then referring to the api storage account in the second template and storing the storage account’s id in a keyvault secret:

multiplestorage.bicep:

@description('Name of Environment')
param environment string = 'test'

param storageAccounts array = [
  {
    name : 'api${environment}${uniqueString(resourceGroup().id)}'
    skuName : 'Standard_LRS'
    accessTier : 'Hot'
  }
  {
    name : 'web${environment}${uniqueString(resourceGroup().id)}'
    skuName : 'Standard_LRS'
    accessTier : 'Hot'
  }
]

resource storage_resource 'Microsoft.Storage/storageAccounts@2021-06-01' = [for storage in storageAccounts: {
  name : storage.name
  location : resourceGroup().location
  sku:{
    name : 'Standard_LRS'
  }
  kind : 'StorageV2'
  properties:{
    accessTier: 'Hot'
    allowBlobPublicAccess: true
    minimumTlsVersion: 'TLS1_2'
    supportsHttpsTrafficOnly: true
    encryption:{
      keySource: 'Microsoft.Storage'
      services:{
        blob:{
          keyType: 'Account'
          enabled: true
        }
        file:{
          keyType: 'Account'
          enabled: true
        }
      }
    }    
  }
}]

output storageAccounts array = [for (name, i) in storageAccounts:{
    storageAccountName : name
}]

module connectionString './functionapp.bicep'=[for (name,i) in storageAccounts :if(startsWith(storage_resource[i].name,'api')){
  name: 'functionappNested${i}'
  params: {
    storageAccounts:storage_resource[i].name
}
}]

functionapp.bicep

param storageAccounts string

resource storageAccount 'Microsoft.Storage/storageAccounts@2019-04-01' existing = {
  name: storageAccounts
}

resource keyVaultShared 'Microsoft.KeyVault/vaults@2021-06-01-preview' existing = {
  name: 'keyvaulttest1234ans'
}
resource storageAccountConnectionString 'Microsoft.KeyVault/vaults/secrets@2021-06-01-preview' = {
  parent:keyVaultShared
  name: '${keyVaultShared.name}-test'
  properties:{
    contentType: 'Storage Account Connection String'
    value: storageAccount.id
}
}

Output:

Note: You can provide the storage account name that starts with web to another nested template as a module and use it for another resource in the same way.

Answered by AnsumanBal-MT

Post is based on https://stackoverflow.com/questions/70671540/using-bicep-can-i-find-a-specific-element-in-an-array-by-a-substring-of-the-name