`jsonencode` bad return

[QuentinBtd]

Describe the bug Using jsonencode with variable value in inputs block generate bad json

To Reproduce Example using this module : https://github.com/cloudposse/terraform-aws-cloudwatch-events The jsonencode function is used in the module: https://github.com/cloudposse/terraform-aws-cloudwatch-events/blob/main/main.tf#L15

In native terraform

provider "aws" {
  region = "eu-west-3"
}

module "cloudwatch_event" {
  source  = "cloudposse/cloudwatch-events/aws"
  version = "0.6.1"

  name      = "test"

  cloudwatch_event_rule_description = "This is event rule description."

  cloudwatch_event_rule_pattern = {
    "source"      = ["aws.autoscaling"]
    "detail-type" = ["EC2 Instance Launch Successful", "EC2 Instance Terminate Successful"]

    "detail" = {
      "AutoScalingGroupName" = ["test"]
    }
  }
  cloudwatch_event_target_arn = "arn:aws:lambda:eu-west-3:000000000000:function:fake"

  context = module.this.context
}

I get this for the cloudwatch rule event_pattern when I run terragrunt plan and it works with apply.

 # module.cloudwatch_event.aws_cloudwatch_event_rule.this will be created
  + resource "aws_cloudwatch_event_rule" "this" {
      + arn            = (known after apply)
      + description    = "This is event rule description."
      + event_bus_name = "default"
      + event_pattern  = jsonencode(
            {
              + detail      = {
                  + AutoScalingGroupName = [
                      + "test",
                    ]
                }
              + detail-type = [
                  + "EC2 Instance Launch Successful",
                  + "EC2 Instance Terminate Successful",
                ]
              + source      = [
                  + "aws.autoscaling",
                ]
            }
        )
      + id             = (known after apply)
      + is_enabled     = true
      + name           = "test"
      + name_prefix    = (known after apply)
      + tags_all       = (known after apply)
    }

With Terragrunt

terraform {
  source = "github.com/cloudposse/terraform-aws-cloudwatch-events//.?ref=0.6.1"
}


### Inputs
inputs = {
  name = "test"

  cloudwatch_event_target_arn = "arn:aws:lambda:eu-west-3:000000000000:function:fake"

  cloudwatch_event_rule_pattern = {
    "source"      = ["aws.autoscaling"]
    "detail-type" = ["EC2 Instance Launch Successful", "EC2 Instance Terminate Successful"]

    "detail" = {
      "AutoScalingGroupName" = ["test"]
    }
  }
}

I get this for the cloudwatch rule event_pattern when I run terraform plan and it fails with apply.

   # aws_cloudwatch_event_rule.this will be created
  + resource "aws_cloudwatch_event_rule" "this" {
      + arn            = (known after apply)
      + description    = "test"
      + event_bus_name = "default"
      + event_pattern  = "\"{\\\"detail\\\":{\\\"AutoScalingGroupName\\\":[\\\"test\\\"]},\\\"detail-type\\\":[\\\"EC2 Instance Launch Successful\\\",\\\"EC2 Instance Terminate Successful\\\"],\\\"source\\\":[\\\"aws.autoscaling\\\"]}\""
      + id             = (known after apply)
      + is_enabled     = true
      + name           = "test"
      + name_prefix    = (known after apply)
      + tags_all       = (known after apply)
    }

Expected behavior The value of event_pattern is badly formatted using Terragrunt

Nice to have

• [x] Terminal output
• [ ] Screenshots

Versions

• Terragrunt version: v1.6.3
• Terraform version: v0.53.2
• Environment details (Ubuntu 20.04, Windows 10, etc.): MacOS 14.1

Additional context

• provider registry.terraform.io/hashicorp/aws v5.24.0
• provider registry.terraform.io/hashicorp/local v2.4.0

[QuentinBtd]

After several more tests, it seems that this happens when jsonencode is used in a module, and not directly in terragrunt.hcl.

[felipevacar]

Any update? I am facing the same issue :(

[github-actions[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for raising this issue.