Metric math alarms: How can I use a for_each expression to loop over metrics within a dynamic block? - foreach

Question

I am trying to create dynamic metric math alarms, that are configurable with a JSON.
I am struggling with looping over the metric alarm with a for_each expression as this is a loop within a loop.
Here is an example of what I am trying to do:
resource "aws_cloudwatch_metric_alarm" "Percentage_Alert" {
for_each = var.percentage_error_details
locals { alarm_details = each.value }
alarm_name = "${terraform.workspace}-${each.key}"
comparison_operator = local.alarm_details["Comparison_Operator"]
evaluation_periods = "1"
threshold = local.alarm_details["Threshold"]
metric_query {
id = "e1"
expression = local.alarm_details["Expression"]
label = local.alarm_details["Label"]
return_data = "true"
}
dynamic "metric_query" {
for metric in each.value["Metrics"]{
id = metric.key
metric_name = metric.value
period = local.alarm_details["Period"]
stat = local.alarm_details["Statistic"]
namespace = local.full_namespace
unit = "Count"
}
}
}
And this is the sample JSON
{
"locals": {
"Name": {
"Name": "metric_math",
"Metrics": {
"m1": "Sucess",
"m2": "Failure"
},
"Expression": "100*(m2/(m1+m2))",
"Threshold" : 1,
"Period": 25,
"Priority": "critical",
"Statistic": "Sum",
"Label": "label",
"Comparison_Operator": "GreaterThanOrEqualToThreshold"
}
}
}
And this is the error message i'm getting:
Error: Invalid block definition
On ../modules/cloudwatch/metriclogfilter/main.tf line 89: Either a quoted
string block label or an opening brace ("{") is expected here.
Any help would be much appreciated.