Unable to expand the Parameters in .bicepparam files

[AhmedValiShaik]

I have a folder structure like below

-.ps-rule
	-Org.Tags.Rule.yaml
-infra
	- modules
		- storageAccount.bicep
	- parameters
		-main.dev.bicepparam
		-main.test.bicepparam
	-main.bicep
-ps-rule.yaml

My main.bicep looks like this

param location string = resourceGroup().location
param responsible string
param env string
param module string
param logWSName string
param sharedResourceGroup string

var defaultTags = {
    module: module
    Environment: env
    Responsible: responsible
}

resource logAnalyticsWorkspaceRes 'Microsoft.OperationalInsights/workspaces@2022-10-01' existing = {
  name:logWSName
  scope:resourceGroup(sharedResourceGroup)
}

module storageAccModule 'modules/storageAccount.bicep'= {
  name: 'StorageAccDeployment_${utcValue}'
  params: {
    env:env
    defaultTags:defaultTags
    location: location
    logAnalyticsWSId: logAnalyticsWorkspaceRes.id
  }
}

My param file looks like this

using '../main.bicep'

param env = 'Demo'
param module = 'Test'
param sharedResourceGroup = 'Test'
param logWSName = 'Test'

My ps-rule.yaml looks like this

binding:
  preferTargetInfo: true
  targetType:
    - type
    - resourceType

# Require minimum versions of modules.
requires:
  PSRule: '>=2.9.0'
  PSRule.Rules.Azure: '>=1.39.1'

# Use PSRule for Azure.
include:
  module:
    - PSRule.Rules.Azure

output:
  culture:
    - 'en-AU'

execution:
  unprocessedObject: Ignore

input:
  pathIgnore:
    - 'infra/modules/*.bicep'
    - '!infra/main.bicep'


configuration:
  
  AZURE_RESOURCE_GROUP:
    location: 'westus'
  
  # Enable Bicep CLI checks.
  AZURE_BICEP_CHECK_TOOL: true

  # Enable automatic expansion of Azure parameter files.
  AZURE_PARAMETER_FILE_EXPANSION: true

  # Enable automatic expansion of Azure Bicep source files.
  AZURE_BICEP_FILE_EXPANSION: true

  AZURE_BICEP_PARAMS_FILE_EXPANSION: true

  # Configures the number of seconds to wait for build Bicep files.
  AZURE_BICEP_FILE_EXPANSION_TIMEOUT: 30

rule:
  # Enable custom rules that don't exist in the baseline
  includeLocal: true

I keep getting the error,

"Unable to expand resources because the source file 'main.bicep' was not valid. An error occurred evaluating expression '[variables('defaultTags')]' line 80. An error occurred evaluating expression '[parameters('module')]'. The parameter named 'module' was not set or a defaultValue was defined."

I found 2 alternatives

1. If I add the AZURE_PARAMETER_DEFAULTS configuration to the ps-rule.yaml, I dont get any error.

 AZURE_PARAMETER_DEFAULTS:
    module: 'test'
    env: 'test'
    responsible: 'test'

2. Make the param have an optional empty string in main.bicep
   param responsible string = ''

Am I missing anything here in ps-rule.yaml or Is there any other way we could solve this ?

[BernieWhite]

Thanks for the question @AhmedValiShaik. Yes, for PSRule to expand the Bicep files it must be able to resolve all parameters, similar to when you deploy to Azure.

If the parameters are optional

Your example in (2) is good. However, you may not want these parameters to be optional.

If the parameters are required

Yes, you can use AZURE_PARAMETER_DEFAULTS to set the default value for any required parameters that are not set. This option is good for scenarios that would normally be automatically set by the pipeline or CLI.

Another option is to create a file specifically for testing that is not deployed. It is mainly used for testing modules in isolation. For example, if you wanted to test storageAccount.bicep then using a test file is the recommended option. (See https://azure.github.io/PSRule.Rules.Azure/using-bicep/#testing-bicep-modules)

For testing a deployment with parameter files, the (1) and (2) are both good options for doing this.

[AhmedValiShaik]

Thank you @BernieWhite