Issue with Deployment of EventGridDomain and ServiceBus BICEP Module

[rebuildtech]

Hi Team

I have an issue with one of the BICEP Module.

I have 2 modules created for 2 of the services, And each service will be deployed into different resource groups.

Lets say, One of the module has a resource called Servicebus in one Resourcegroup.
I have another resource eventgrid in another resourcegroup

However the eventgrid has a dependency for eventsubscription endpoint type as Servicebustopic. In order to acheive this, I am using the existing resource type for servicebus in the eventgrid module and referring the servicebustopic name as parameter. This servicebustopicname value. I am pulling it from the resourcename of servicebus topic which i am creating in service bus module

However, when i deploy the service bus module, it is successfully deployed without any issues. But when it comes to the eventgrid module deployment. I get this error.

New-AzResourceGroupDeployment: The deployment 'test-rg-evt' failed with error(s). Showing 1 out of 1 error(s).
Status Message: Unable to process template language expressions for resource '/subscriptions/%SubscriptionID%/resourceGroups/%RGName%/providers/Microsoft.EventGrid/domains/Eventgridname/topics/eventdomaintopicname/eventSubscriptions/eventsubscriptionanme' at line '61' and column '9'. 'The language expression property array index '1' is out of bounds.' (Code:InvalidTemplate)

I dont understand the issue as i am not passing any array values anywhere in the whole context. Can someone please guide me on this if possible ?

I am pretty much new to BICEP and trying to learn it.

[StefanIvemo]

Hey @rebuildtech! Can you please share your code? Both the module templates and your main file.

[brwilkinson]

In simple terms, I think it's best to always create the existing resource in the module or scope that you are using it.

So you need to establish the existing in that module. Pass in any names that you need to do that.

[rebuildtech]

But in my case i need the servicebus to be deployed first in a different resource group (Hence i am using a different module file to create that already ) and then i have to go with the eventgrid deployment.

i have many more other modules combined. However, it is just eventgrid that needs a reference to servicebus and no other module really needs that.

Hence i cannot create that resource here.

[brwilkinson]

You need to have the existing lookup in any Module that needs to cross reference it.

It's fairly simple. However don't try to "pass" an existing resource. We don't have that functionality yet. You pass the name, then use the existing syntax.

You can have every resource type in its own Module. Then cross reference as needed.

There are examples here for most resource types...

https://github.com/brwilkinson/AzureDeploymentFramework/tree/main/ADF/bicep

[brwilkinson]

put this code in the module eventGridDomain 'Eventgrid-eventhandler/EventGridMain.bicep'

resource namespace 'Microsoft.ServiceBus/namespaces@2021-11-01' existing = {
  name: namespacename
  scope: resourceGroup(servicebusresourcegroupname)

  // notice i am nested, I have a short name, no parent and no api version
  resource servicebustopic 'topics' existing = {
    name: servicebustopicname
  }
}

Then when you call the module pass in the arguments that you need

module eventGridDomain 'Eventgrid-eventhandler/EventGridMain.bicep' = {
  name: '${eventGridDomainName}-${deploymentEnvironment}-0007'
  params: {
    eventGridDomainName: '${eventGridDomainName}-${deploymentEnvironment}-0007'
    eventGridDomainTopicName: '${eventGridTopicName}-${deploymentEnvironment}-0007'
    eventSubscriptionName: '${eventSubscriptionName}-${deploymentEnvironment}-0007'
    deploymentEnvironment: deploymentEnvironment
    location: location
    serviceBusTopicName: servicebustopicname
    namespacename: namespacename
  }
}

[brwilkinson]

if you have a good naming standard (which you should), then you don't even need to pass in the extra parameters, you can determine what the servicebus name would be based on the standard.... then you could just pass in the topic name etc