Looping support for Resource Properties

[Jaa9]

Azure Application Gateway is an example of a resource in Azure with a lot of properties (and also sometimes subproperties) that needs to loop/iterate from one or more variable tables to be able to reuse and create readable and manageable templates. Will bicep enable us to overcome ARM Template complexity and difficulties?

[alex-frankel]

We now have loops support in bicep - have you had a chance to use it? Would be great to get a sense if this is easier than how it would be accomplished in ARM templates.

https://github.com/Azure/bicep/blob/main/docs/tutorial/05-loops-conditions-existing.md#loops

[joelmforsyth]

Hey @alex-frankel I think I understand what @Jaa9 is asking for. I'm writing a a Bicep file to create and populate a Data Factory with Linked Services, Datasets, and Pipelines. I created a variable to store, for example, an array of containers in blob storage.

I understand I can loop through the array to create the resources for the Linked Services and Datasets, but I'm trying to keep all the activities related to a single storage account in a single pipeline. Since my dataset resources are now an array, and pipeline activities are 1:1 with datasets, I need to add activities to the pipeline based on how many datasets were created.

Based on the syntax it looks like I can only loop to add resources not properties which would include pipeline activities. Is it expected that I should just hard-code the index of the dataset resource when adding an activity for it?

[joelmforsyth]

This looks like it was added a few days ago: https://github.com/Azure/bicep/blob/main/docs/spec/loops.md

[alex-frankel]

Correct this was released recently. @joelmforsyth / @Jaa9 is this resolved?

[joelmforsyth]

I believe so, @alex-frankel . My only question now is about adding dependencies after a resource is referenced in a looping property. For instance, in Data Factory all of the Activities are within properties. So if I were to add a Copy activity to move an array of Cosmos DB collections to a connected array of blob storage containers with looping properties, how would I make sure the dependencies are added correctly?

The tutorial has the line

dependsOn will be added when the template is compiled

Does that mean Bicep will take care of the dependencies automatically?

[alex-frankel]

I'm not sure what this Data Factory template would look like, but assuming there is a reference to a declared storage account container's symbolic name, then the dependsOn will be automatically added. See implict dependencies