Specify Function App Configuration with Key Vault Reference in Azure ARM Template

Question

Is there a way to specify KeyVault References in Function App configuration within my ARM template?

I have an ARM template that will deploy an Azure Function App with different deploy parameter for each environment. Currently I am retrieving the secret in my environment via references in the parameter:

{
"storageAccountSecret": {
    "reference": {
        "keyVault": {
             "id": "/subscriptions/plan-id-goes-here/resourceGroups/group-name-goes-here/providers/Microsoft.KeyVault/vaults/vault-name-goes-here"
         }, 
         "secretName": "super-secret-name-goes-here"
     }
}

I then reference the parameter in the ARM template, resources -> properties -> siteConfig -> appSettings

 {
   "name": "AzureWebJobsStorage",
   "value": "[parameters('storageAccountSecret')]"
 },

Above works fine! However, our team also periodically rotate our keys which change the underlying value of the secret. With my current approach, the secret on this function app config won't update until we run the ARM template again.

My get around is to use KeyVault Reference in the config, with the following syntax in the configuration.

@Microsoft.KeyVault(SecretUri=https://vault-name-goes-here.vault.azure.net/secrets/super-secret-name-goes-here/)

Now when the underlying secret changes, my function App will still get the up to date secret. However this require me to do it manually. I would love to achieve the same effect with just the ARM template alone, is that possible? ????

silent silent · Accepted Answer · 2019-10-31T14:48:29

For exactly that reason you should always use the full URL to your secrets in Key Vault - including the version. See here.

When you update a secret in Key Vault, you get a new URL. Once you update the app setting (through your ARM template or any other way), the Function will be restarted. This is the desired behavior when updating app settings.

Specify Function App Configuration with Key Vault Reference in Azure ARM Template

1 Answers