How to enable IF condition on terrafrom modules

Question

I need to create TF CloudWatch Metrices only of the env is QAT and PROD. Currently using TF modules to create those in all env.

module "aws_cloudwatch_log_metric_filter" {
  source = "https://github.com/modules.git//aws-cloudwatch-log-metric-filter"
  log_group_name = "/aws/lambda/${var.lambda_name}"
  pattern = "{$.message = \"---------------- Message ----------------\"}"
}

locals {
  base_tags = {
    environment      = var.environment
  }
}

Main resource where I am calling module.

resource "aws_cloudwatch_log_metric_filter" "log_metric" {
  count          = var.count
  name           = "Metric"
  pattern        = var.pattern
  log_group_name = var.log_group_name
    
  metric_transformation {
    name      = "name"
    namespace = "namespace"
      value     = "1"
      default_value = "0"
  }
}

Answer 1

You could do this in the module:

resource "aws_cloudwatch_log_metric_filter" "log_metric" {
  count          = var.environment == "QAT" || var.environment == "PROD" ? 1 : 0
  name           = "Metric"
  pattern        = var.pattern
  log_group_name = "${var.environment}-${var.log_group_name}"

  metric_transformation {
    name      = "name"
    namespace = "namespace"
    value     = "1"
    default_value = "0"
  }
}

The log_group_name = "${var.environment}-${var.log_group_name}" will ensure you don't get issues with the same log group name.