How To Get Azure App Configuration Connection String In ARM Template
App Configuration is a service in Azure that helps manage application settings and feature flags, this could be very useful in a distributed environment.
If you are using ARM templates to author your resources, you might want to retrieve a connection string from a newly created or already existing resource to pass it as a parameter to an application or just use it for some scripts inside of your deployment pipeline.
In this short post we will see how to get a connection string for Microsoft.AppConfiguration/configurationStores resource in the ARM template.
Contents:
listKeys function
We will use ARM template listKeys function to get keys data about the App Configuration resource. The syntax is the following:
listKeys(resourceName or resourceIdentifier, apiVersion)
App Configuration’s implementation of listKeys function invokes this API method under the hood, this link contains the contract and the response structure of this endpoint.
In general, listKeys return object varies depending on the resource and in case of the App Configuration it has the following structure (apiVersion 2020-06-01):
{
"value": [
{
"id": "bmk/-l1-s0:wreIfHE5AVdfbuUQdiB/",
"name": "Primary",
"value": "rvS7jvukwlyep0mI8qYgR6b3y6QN71UkSSKBmxcsjjU=",
"connectionString": "Endpoint=https://cfg-contoso.azconfig.io;Id=bmk/-l1-s0:wreIfHE5AVdfbuUQdiB/;Secret=rvS7jvukwlyep0mI8qYgR6b3y6QN71UkSSKBmxcsjjU=",
"lastModified": "2021-02-14T04:46:26+00:00",
"readOnly": false
},
{
"id": "bSMo-l1-s0:E2Ji37cEdkaQr3CadNR9",
"name": "Secondary",
"value": "+qgLfIdpBBqUrS7SVlPdhN8W9e+zk+F15WAUtddsJQI=",
"connectionString": "Endpoint=https://cfg-contoso.azconfig.io;Id=bSMo-l1-s0:E2Ji37cEdkaQr3CadNR9;Secret=+qgLfIdpBBqUrS7SVlPdhN8W9e+zk+F15WAUtddsJQI=",
"lastModified": "2021-02-14T04:46:26+00:00",
"readOnly": false
},
{
"id": "WAYb-l1-s0:VQXvOdg0XNWrPvMaE+o3",
"name": "Primary Read Only",
"value": "e4Nt5LzW93InEtZZMGLM28bYTNIDW59m8ZMrG4Nb8yU4=",
"connectionString": "Endpoint=https://cfg-contoso.azconfig.io;Id=WAYb-l1-s0:VQXvOdg0XNWrPvMaE+o3;Secret=e4Nt5LzW93InEtZZMGLM28bYTNIDW59m8ZMrG4Nb8yU4=",
"lastModified": "2021-02-14T04:46:26+00:00",
"readOnly": true
},
{
"id": "iREd-l1-s0:7aYj/Q2+mx3oTCI7x2sp",
"name": "Secondary Read Only",
"value": "/EKUA1/7e7RL93tFpe9SLXQzhU3BJ0/i8r47jX+pGjg=",
"connectionString": "Endpoint=https://cfg-contoso.azconfig.io;Id=iREd-l1-s0:7aYj/Q2+mx3oTCI7x2sp;Secret=/EKUA1/7e7RL93tFpe9SLXQzhU3BJ0/i8r47jX+pGjg=",
"lastModified": "2021-02-14T04:46:26+00:00",
"readOnly": true
}
]
}
Getting connectionString
Now, given the output from the listKeys function above, it is very simple how to get a connection string for the configuration store.
The return object contains an array of 4 keys: Primary, Secondary, Primary Read Only, Secondary Read Only. We just need to select the key we are interested in, below is an example for connectionString of Primary key.
NOTE: Specify an array index for the value property to access the desired key. In the following example it is set to 0 to get Primary key.
"[listKeys(resourceId('Microsoft.AppConfiguration/configurationStores', parameters('resourceName')), '2020-06-01').value[0].connectionString]"
Also, here is an example of ARM template that outputs connectionString of the App Configuration resource specified in the parameters (in this case cfg-contoso). You can use it in your template in a similar way.
{
"$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentTemplate.json#",
"contentVersion": "1.0.0.0",
"parameters": {
"resourceType": {
"defaultValue": "Microsoft.AppConfiguration/configurationStores",
"type": "String"
},
"resourceName": {
"defaultValue": "cfg-contoso",
"type": "String"
},
"apiVersion": {
"defaultValue": "2020-06-01",
"type": "String"
}
},
"resources": [],
"outputs": {
"connectionString": {
"type": "String",
"value": "[listKeys(resourceId(parameters('resourceType'), parameters('resourceName')), parameters('apiVersion')).value[0].connectionString]"
}
}
}