[FEATURE REQ] Support objects in parameters.json file

[pim-simons]

Please describe the feature or suggestion.

We are using quite a lot of objects in our parameters.json files to nicely combine several parameters, also described here, for example:

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentParameters.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "infra": {
      "value": {
        "environment": {
          "resourcePrefix": "dummy",
          "resourceGroupName": "dummy"
        }
      }
    }
  }
}

We can then access that value from our Bicep file like this infra.environment.resourcePrefix.

When running the Template Analyzer tool this does not seem to be supported as I run into these kind of errors:
The template variable 'appSettings' is not valid: The language expression property 'environment' doesn't exist, available properties are 'property1'...

It seems like using objects in the parameters file are not supported, or am I doing something wrong? Searched within the documentation and issues but couldn't really find anything.
Would be great if this could be supported!

Additional context

Entire error:

Warning: An exception occurred when processing the template language expressions
Exception details:
Azure.Deployments.Templates.Exceptions.TemplateValidationException: The template variable 'appSettings' is not valid: The language expression property 'environment' doesn't exist, available properties are 'property1'.. Please see https://aka.ms/arm-template-expressions for usage details.
 ---> Azure.Deployments.Core.Exceptions.ExpressionException: The language expression property 'environment' doesn't exist, available properties are 'property1'.
   at Azure.Deployments.Expression.Expressions.FunctionExpression.SelectObjectProperty(JObject root, JToken token, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Expression.Expressions.FunctionExpression.SelectProperty(JToken root, JToken property, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Expression.Expressions.FunctionExpression.EvaluateExpression(ExpressionEvaluationContext context, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Expression.Expressions.FunctionExpression.<>c__DisplayClass23_0.<EvaluateParameters>b__0(LanguageExpression parameter)
   at System.Array.ConvertAll[TInput,TOutput](TInput[] array, Converter`2 converter)
   at Microsoft.WindowsAzure.ResourceStack.Common.Extensions.IEnumerableExtensions.SelectArray[TSource,TElement](TSource[] source, Converter`2 elementSelector)
   at Azure.Deployments.Expression.Expressions.FunctionExpression.EvaluateParameters(ExpressionEvaluationContext context, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Expression.Expressions.FunctionExpression.EvaluateExpression(ExpressionEvaluationContext context, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Expression.Engines.ExpressionsEngine.EvaluateLanguageExpressionsInternal(JToken root, ExpressionEvaluationContext evaluationContext, Boolean ignoreExceptions, TemplateErrorAdditionalInfo additionalInfo, InsensitiveHashSet skipEvaluationPaths)
   at Azure.Deployments.Expression.Engines.ExpressionsEngine.EvaluateLanguageExpressionsRecursive(JToken root, ExpressionEvaluationContext evaluationContext, TemplateErrorAdditionalInfo additionalInfo, InsensitiveHashSet skipEvaluationPaths)
   at Azure.Deployments.Templates.Engines.TemplatePreprocessingEngine.ProcessTemplateVariableLanguageExpressionsRecursive(Template template, String variableName, InsensitiveDictionary`1 recursionState, ExpressionEvaluationContext evaluationContext, TemplateErrorAdditionalInfo additionalInfo)
   --- End of inner exception stack trace ---
   at Azure.Deployments.Templates.Engines.TemplatePreprocessingEngine.ProcessTemplateVariableLanguageExpressionsRecursive(Template template, String variableName, InsensitiveDictionary`1 recursionState, ExpressionEvaluationContext evaluationContext, TemplateErrorAdditionalInfo additionalInfo)
   at Azure.Deployments.Templates.Engines.TemplatePreprocessingEngine.ProcessTemplateVariablesLanguageExpressions(Template template, String apiVersion, InsensitiveDictionary`1 functionEvaluationOverwrites)
   at Azure.Deployments.Templates.Engines.TemplatePreprocessingEngine.ProcessTemplateLanguageExpressions(String managementGroupName, String subscriptionId, String resourceGroupName, Template template, String apiVersion, InsensitiveDictionary`1 functionEvaluationOverwrites)
   at Azure.Deployments.Templates.Engines.TemplateEngine.ProcessTemplateLanguageExpressions(String managementGroupName, String subscriptionId, String resourceGroupName, Template template, String apiVersion, InsensitiveDictionary`1 functionEvaluationOverwrites)
   at Microsoft.Azure.Templates.Analyzer.TemplateProcessor.ArmTemplateProcessor.ParseAndValidateTemplate(InsensitiveDictionary`1 parameters, InsensitiveDictionary`1 metadata) in C:\temp\template-analyzer-0.3.1\src\Analyzer.TemplateProcessor\ArmTemplateProcessor.cs:line 131
Warning: An exception occurred while evaluating the properties of a resource.

[VeraBE]

@pim-simons, can you share a template that triggers an error message like that? I tried but couldn't reproduce it, this works fine:

{
    "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
    "contentVersion": "1.0.0.0",
    "parameters": {
      "anObjectParam": {
        "type": "object",
        "defaultValue": {
          "environment": {
            "location": "aLocation"
          }
        }
      }
    },
    "resources": [
        {
            "type": "Microsoft.MachineLearningServices/workspaces",
            "name": "aWorkspace",
            "apiVersion": "2016-12-01",
            "location": "[parameters('anObjectParam').environment.location]",
            "properties": {}
        }
    ]
}

[JohnathonMohr]

I believe the issue is when a template doesn't define a default value for the object. The value used during analysis is a mocked object, which will not have the expected properties during template expansion, and fail to parse.

[JohnathonMohr]

@pim-simons a possible workaround is to analyze templates individually and specify the parameters file to use with -p on the command line. Auto-discovery of parameters when analyzing a directory isn't supported right now.

[pim-simons]

I am indeed using a separate parameters json file.
@VeraBE here is an example of a bicep file and a separate parameters json file causing the issue:

@description('Provide the object that contains all info about the common infrastructure.')
param infra object

resource applicationInsight 'microsoft.insights/components@2020-02-02' = {
  name: 'test'
  location: infra.environment.location
  kind: 'other'
}

{
  "$schema": "https://schema.management.azure.com/schemas/2015-01-01/deploymentParameters.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {
    "infra": {
      "value": {
        "environment": {
          "location": "West Europe"
        }
      }
    }
  }
}

When I use the TemplateAnalyzer.exe analyze-directory command this fails with the error The language expression property 'environment' doesn't exist, available properties are 'property1'...
When I use the TemplateAnalyzer.exe analyze-template with the -p command then it works fine indeed 👍🏻:

Parameters File: D:\temp\template.parameters.json

        Rules passed: 0

Execution summary:
        The execution completed successfully

@JohnathonMohr thanks for the workaround!!
Is the auto-discovery of parameters when analyzing a directory on the roadmap?

[VeraBE]

@pim-simons, auto-discovery of parameters files is not a high priority for us yet

[pim-simons]

@pim-simons, auto-discovery of parameters files is not a high priority for us yet

No worries, thanks for the heads up!
In the meantime, I figured I'd try to contribute and created a PR for this 😅

[pamelafox]

I believe I've run into this issue or a similar issue, just want to confirm that I shouldn't open another issue.

Github workflow run:

https://github.com/pamelafox/simple-flask-server-example/actions/runs/4492404425/jobs/7902240790?pr=3

Errors on functions.bicep, which has this line:

param appSettings object = {}

This particular Bicep file isn't used in this infra, so there are no parameters being specified in a parameters.json. The template-analyzer errors with:

 Error: An exception occurred while analyzing template /home/runner/work/simple-flask-server-example/simple-flask-server-example/infra/core/host/functions.bicep
    Exception details:
    Microsoft.Azure.Templates.Analyzer.Core.TemplateAnalyzerException: Error while evaluating rules.
     ---> Microsoft.Azure.Templates.Analyzer.Core.TemplateAnalyzerException: Error while processing template.
     ---> Azure.Deployments.Templates.Exceptions.TemplateValidationException: Template parameter 'appSettings' was provided an invalid value. Expected a value of type 'Object', but received a value of type 'String'. Please see https://aka.ms/resource-manager-parameter-files for usage details.
       at Azure.Deployments.Templates.Engines.TemplateValidationEngine.ValidateParameterJTokenType(String parameterName, JTokenType parameterJTokenType, TemplateErrorAdditionalInfo additionalInfo, JTokenType[] expectedJTokenTypes)
       at Azure.Deployments.Templates.Engines.TemplateValidationEngine.ValidateParameterValue(String parameterName, TemplateParameter parameter)
       at Azure.Deployments.Templates.Engines.TemplateParameterizationEngine.ParameterizeInputParameter(String parameterName, TemplateInputParameter parameter, InsensitiveDictionary`1 inputParameters, ExpressionEvaluationContext evaluationContext, Boolean ignoreEvaluationExceptionsForWhatIf)