ARM templates, Make an Http request - arm-template

Question

I was looking into adding a step that makes an HTTP request from ARM templates after I finish the swapping operation. Is it something doable using ARM templates?

Answer 1

ARM templates have no build-in methods to perform HTTP requests. If you absolutely must call an HTTP endpoint from your template, you can deploy a deployment script resource. This is a temporary container resource that executes a script and can be configured to be automatically removed after it ran sucessfully. In your case that might be a lot of infrastructure overhead for very little function.
An alternative approach would be to use your ARM template to deploy an Event Grid event subscription. The event subscription can be configured to call a webhook or an Azure Function every time a slot swap is completed successfully on your app:
Here is an example:
"resources": [
{
"type": "Microsoft.EventGrid/systemTopics",
"apiVersion": "2020-10-15-preview",
"name": "{{ SYSTEM_TOPIC_NAME }}",
"location": "{{ LOCATION }}",
"properties": {
"source": "{{ RESOURCE_ID_OF_APP }}",
"topicType": "Microsoft.Web.Sites"
}
},
{
"type": "Microsoft.EventGrid/systemTopics/eventSubscriptions",
"apiVersion": "2020-10-15-preview",
"name": "{{ SYSTEM_TOPIC_NAME }}/{{ EVENT_SUBSCRIPTION_NAME }}",
"dependsOn": [
"[resourceId('Microsoft.EventGrid/systemTopics', '{{ SYSTEM_TOPIC_NAME }}')]"
],
"properties": {
"destination": {
"properties": {
"maxEventsPerBatch": 1,
"preferredBatchSizeInKilobytes": 64,
"endpointUrl": "{{ WEBHOOK_URL }}"
},
"endpointType": "WebHook"
},
"filter": {
"includedEventTypes": [
"Microsoft.Web.SlotSwapCompleted"
],
"enableAdvancedFilteringOnArrays": true
},
"labels": [],
"eventDeliverySchema": "EventGridSchema",
"retryPolicy": {
"maxDeliveryAttempts": 30,
"eventTimeToLiveInMinutes": 1440
}
}
}
]