Make terraform module creation fail based on a condition - terraform

Question

I am trying to leverage precondition hook to check for an input to a module creation in terraform.
module "groups" {
source = "../path/to/groups"
for_each = var.groups.groups
name = each.key
type = each.value.type
policies = each.value.policies
depends_on = [
module.policies
]
lifecycle {
precondition {
condition = alltrue([ for item in self.policies :
alltrue([ for p in item : contains(locals.policies_list, p) ]) ] )
error_message = format("Attempt to create a group with a non existing policy")
}
}
}
However, although:
terraform --version --json
{
"terraform_version": "1.3.7",
"platform": "linux_amd64",
"provider_selections": {},
"terraform_outdated": false
}
This fails:
The block type name "lifecycle" is reserved for use by Terraform in a future version.
Is this because the specific functionality is not available in terraform for module creation? Is there a way around making my module creation fail based on the above condition?

Answer 1

Unfortunately the lifecycle block is not available for a module.
A way around this is the following
module "groups" {
source = "../path/to/groups"
for_each = var.groups.groups
name = each.key
type = each.value.type
policies = each.value.policies
depends_on = [
null_resource.group_check,
module.policies
]
}
resource "null_resource" "group_check" {
for_each = var.groups.groups
lifecycle {
precondition {
condition = alltrue([for p in each.value.policies : contains(local.policies_list, p)])
error_message = format("Attempt to create a group with a non existing policy")
}
}
depends_on = [
module.policies
]
}