Can I deploy an event trigger to Function App via Bicep? - azure

Question

I aim to create such a bicep file that would deploy a function app with an event trigger in it, however, I'm not sure if it's possible. I've tried googling but Function App deployment via bicep tutorials tend to stop right after the deployment of an empty function app. I need to go a step further and add triggers to it.
Why do I want to deploy at least an empty event trigger via bicep?
The core of the issue is: I would like to perform two stages of CD, where the first one will be all about bicep (preparing all of the resources) and the second one about code deployment.
However, at the first CD stage, the following error occurs:
{"code":"Endpoint validation","message":"Destination endpoint not
found. Resource details: resourceId:
/subscriptions/.../functionAppNameHere/functions/eventTriggerFuncName.
Resource should pre-exist before attempting this operation.}
I assume that EventGrid EventSubscriptions requires prior presence of a resource with the trigger (seems understandable though).
Is it even possible to add an event trigger via bicep so it would move smoothly to event subscription creation? If yes: can you please give me some tips?, if no: do you have any ideas on how to circumvent this?
Here are my bicep files that may come in handy when thinking about the issue:
main.bicep
module azStorageAccount 'modules/azStorageAccount.bicep'= {
name: '${deployName}-st'
params: {
location: location
name: '${stNamePrefix}${resourceSuffix}'
}
}
module azAppInsights 'modules/azAppInsights.bicep' = {
name: '${deployName}-appi'
params: {
location: location
name: '${appiNamePrefix}${resourceSuffix}'
}
}
module azHostingPlan 'modules/azHostingPlan.bicep' = {
name: '${deployName}-asp'
params: {
location: location
name: '${aspNamePrefix}${resourceSuffix}'
}
}
module azFunctionApp 'modules/azFunctionApp.bicep' = {
name: '${deployName}-func'
params: {
storageId:azStorageAccount.outputs.storageId
storageName: azStorageAccount.outputs.storageName
azAppInsightsInstrumentationKey: azAppInsights.outputs.azAppInsightsInstrumentationKey
location: location
name: '${funcNamePrefix}${resourceSuffix}'
serverFarmId: azHostingPlan.outputs.azHostingPlaniD
}
}
module azEventGrid 'modules/azEventGrid.bicep' = {
name: '${deployName}-evg'
params: {
subscription: subscription
evgtName: '${evgtNamePrefix}${resourceSuffix}'
evgsName: '${evgsNamePrefix}${resourceSuffix}'
resourceId: '/subscriptions/${subscription}/resourceGroups/${resourceGroup}/providers/Microsoft.Web/sites/${funcNamePrefix}${resourceSuffix}/functions/${eventFunction}'
}
}
modules/azFunctionApp
// params here
resource azFunctionApp 'Microsoft.Web/sites#2021-03-01' = {
name: name
kind: kind
location: location
identity: {
type: 'SystemAssigned'
}
properties: {
httpsOnly: true
serverFarmId: serverFarmId
clientAffinityEnabled: true
reserved: true
siteConfig: {
appSettings: [
{
name: 'FUNCTIONS_EXTENSION_VERSION'
value: '~3'
}
// more settings here
]
alwaysOn: false
}
}
}
modules/azEventGrid
// params here
resource azEventGridSystemTopic 'Microsoft.EventGrid/systemTopics#2022-06-15' = {
name: evgtName
location: 'global'
tags: {
// tags
}
properties: {
source: '/subscriptions/${subscription}'
topicType: 'Microsoft.Resources.Subscriptions'
}
}
resource azEventGridEventSubscriptions 'Microsoft.EventGrid/systemTopics/eventSubscriptions#2022-06-15' = {
parent: azEventGridSystemTopic
name: evgsName
properties: {
destination: {
properties: {
resourceId: resourceId
maxEventsPerBatch: 1
preferredBatchSizeInKilobytes: 64
}
endpointType: 'AzureFunction'
}
filter: {
includedEventTypes: [
'Microsoft.Resources.ResourceWriteSuccess'
'Microsoft.Resources.ResourceDeleteSuccess'
]
enableAdvancedFilteringOnArrays: true
}
labels: []
eventDeliverySchema: 'EventGridSchema'
retryPolicy: {
maxDeliveryAttempts: 30
eventTimeToLiveInMinutes: 1440
}
}
}