Prevent a Terraform resource with for_each from being created depending on a condition - foreach

Question

I'm using the following resources to create a DynamoDB table with items from a JSON file of objects.
module "dynamodb_label" {
source = "./modules/labels"
enabled = var.ENABLE_TABLE
name = var.dynamodb_name
context = module.this.context
}
locals {
json_data = file("./items.json")
items = jsondecode(local.json_data)
}
module "dynamodb_table" {
source = "./aws-dynamodb"
count = var.ENABLE_TABLE ? 1 : 0
hash_key = "schema"
hash_key_type = "S"
autoscale_write_target = 50
autoscale_read_target = 50
autoscale_min_read_capacity = 5
autoscale_max_read_capacity = 1000
autoscale_min_write_capacity = 5
autoscale_max_write_capacity = 1000
enable_autoscaler = true
enable_encryption = true
enable_point_in_time_recovery = true
ttl_enabled = false
dynamodb_attributes = [
{
name = "schema"
type = "S"
}
]
context = module.dynamodb_label.context
}
resource "aws_dynamodb_table_item" "dynamodb_table_item" {
for_each = var.ENABLE_TABLE ? local.items : {}
table_name = module.dynamodb_table.table_name
hash_key = "schema"
item = jsonencode(each.value)
depends_on = [module.dynamodb_table]
}
The JSON file
{
"Item1": {
"schema": {
"S": "https://schema.org/government-documents#id-card"
},
"properties": {
"S": "{\"documentName\":{\"type\":\"string\"},\"dateOfBirth\":{\"type\":\"string\"}}"
}
},
"Item2": {
"schema": {
"S": "https://schema.org/government-documents#drivers-license"
},
"properties": {
"S": "{\"documentName\":{\"type\":\"string\"},\"dateOfBirth\":{\"type\":\"string\"}}"
}
}
}
I'm getting the following error
Error: Inconsistent conditional result types
on dynamodb-table.tf line 173, in resource "aws_dynamodb_table_item" "dynamodb_table_item":
173: for_each = var.ENABLE_TABLE ? local.items : {}
├────────────────
│ local.items is object with 13 attributes
│ var.ENABLE_TABLE is a bool, known only after apply
The true and false result expressions must have consistent types. The given expressions are object and object, respectively.
I've tried many options to pass this error even change the variable type from bool to object. If I remove the condition in for_each and just pass local.items the aws_dynamodb_table_item tries to create regardless of the depends_on and it fails of course to create because table_name is returned empty because of count = module.dynamodb_label.enabled ? 1 : 0 in dynamodb_table module
I want the aws_dynamodb_table_item to be skipped if var.ENABLE_TABLE is set to false
What am I missing here? Any hint is highly appreciated.
EDIT: Tried the following so far all with same error;
for_each = var.ENABLE_TABLE == true ? local.schemas : {}
for_each = var.ENABLE_TABLE ? local.items : {}

Answer 1

Maybe you can try this:
resource "aws_dynamodb_table_item" "dynamodb_table_item" {
for_each = var.ENABLE_TABLE : local.items ? {}
table_name = module.dynamodb_table.table_name
hash_key = "schema"
item = jsonencode(local.for_each)
depends_on = [module.dynamodb_table]
}
EDIT: in this case the variable var.ENABLE_TABLE must be boolean.

Answer 2

After experimenting for 2 days around different types of expressions to get around this issue a kind sir on Reddit referred to this solution and it worked like a charm;
for_each = { for k,v in local.items : k => v if var.ENABLE_TABLE }
For anyone with a similar requirement this seems a gem that I have missed and recommend you to use it.

Answer 3

The true and false result expressions must have consistent types. The given expressions are object and object, respectively.
I think I found what's the issue is
You should've used jsondecode but used jsonencode instead.
locals {
json_data = file("./items.json")
items = jsondecode(local.json_data)
}
Secondly I run into this issue
╷
│ Error: Incorrect attribute value type
│
│ on main.tf line 14, in resource "aws_dynamodb_table_item" "dynamodb_table_item":
│ 14: item = each.value
│ ├────────────────
│ │ each.value is object with 2 attributes
│
│ Inappropriate value for attribute "item": string required.
╵
╷
│ Error: Incorrect attribute value type
│
│ on main.tf line 14, in resource "aws_dynamodb_table_item" "dynamodb_table_item":
│ 14: item = each.value
│ ├────────────────
│ │ each.value is object with 2 attributes
│
│ Inappropriate value for attribute "item": string required.
For that I used this
resource "aws_dynamodb_table_item" "dynamodb_table_item" {
for_each = var.ENABLE_TABLE ? local.items : {}
table_name = module.dynamodb_table.table_name
hash_key = "schema"
item = each.value.properties.S
depends_on = [module.dynamodb_table]
}
Hope this helps you debug.