Custom types for Bicep

[johnnyreilly]

Apologies if this is a dupe - I've scanned the open issues and didn't spot it.

Is your feature request related to a problem? Please describe.

Consider the following:

@description('The config for the eventhubs')
param eventHubConfigs array = []

The type of the above will be an array of any. It's going to be exercised by something like this:

module senderEventHub '../../../infra/eventhub/main.bicep' = {
  name: 'senderEventHubDeploy'
  params: {
    location: location
    env: env
    tags: tags
    eventHubNamespaceName: senderEventHubNamespaceName
    eventHubConfigs: [
      // note the type here
      {
        name: 'echo_v4'
        messageRetentionInDays: eventHubMessageRetentionInDays
        partitionCount: eventHubPartitionCount
      }
    ]
    // ...
  }
}

Unless I'm missing something in the docs there doesn't seem to be a way to define a custom type which could be used to more directly describe the type of the array. This means people can supply invalid values.

Describe the solution you'd like

It would be amazing if there was a way to specify a custom type. eg:

type EventHubConfig {
    name: string
    messageRetentionInDays: number
    partitionCount: number
}

which could be used something like this:

@description('The config for the eventhubs')
param eventHubConfigs array<EventHubConfig> = []

What do you think?

[shenglol]

Related to #622.

[alex-frankel]

FWIW, I think this is two step process:

1. Allow referencing existing resource property types (i.e. Microsft.Storage.StorageAccounts('2020-06-01').sku)
2. Allow for full custom types - particularly when defining parameter types for modules as you've described

[hansmbakker]

I think this is a duplicate of #8673?

[jeskew]

Closing as duplicate of #4158