Looking for a more concise way of doing a nested loop - terraform

Question

Looking for a cleaner/more-readable way to achieve a nested loop in Terraform. I will illustrate with an example.
Let's say we have variable for roles that looks like this:
variable "roles" {
type = "list"
default = [
{
name = "LOADER"
schemas = {
RAW = ["USAGE", "ALL"]
SRC = ["ALL"]
}
},
{
name = "USER"
schemas = {
RAW = ["DELETE", "OBJECT"]
SRC = ["USE"]
}
}
]
}
From this, I want to end up with a List of dictionaries that looks something like:
output = [
{
"privilege" = "USAGE"
"role" = "LOADER"
"schema" = "RAW"
},
{
"privilege" = "ALL"
"role" = "LOADER"
"schema" = "RAW"
},
{
"privilege" = "ALL"
"role" = "LOADER"
"schema" = "SRC"
},
{
"privilege" = "DELETE"
"role" = "USER"
"schema" = "RAW"
},
{
"privilege" = "OBJECT"
"role" = "USER"
"schema" = "RAW"
},
{
"privilege" = "USE"
"role" = "USER"
"schema" = "SRC"
},
]
What I have tried so far (seems to work but I am looking for a more concise/readable way to do it):
locals {
# FlatMapping to a list of dictionaries. Each dict in the form of {schema=<schema>, role=<role>, privilege=<privilege>}
key_val = [for role in var.roles : [for schema, privilege in role["schemas"]: {
role = role["name"]
schema = schema
privilege = privilege
}]]
other_key_val = [for dict in flatten(local.key_val): [for priv in dict["privilege"]: {
role = dict["role"]
schema = dict["schema"]
privilege = priv
}]]
}
output "output" {
value = flatten(local.other_key_val)
}
My main objective is to have readable code that can be understood better by others. Given that I am using loops in Terraform for the first time, I can't judge if my implementation is considered readable.

Answer 1

Maybe this would be a little bit simpler way to achieve the same result:
locals {
roles = [
{
name = "LOADER"
schemas = {
RAW = ["USAGE", "ALL"]
SRC = ["ALL"]
}
},
{
name = "USER"
schemas = {
RAW = ["DELETE", "OBJECT"]
SRC = ["USE"]
}
}
]
out = flatten([
for item in local.roles: [
for schema, privileges in item.schemas: [
for privilege in privileges: {
role = item.name
privilege = privilege
schema = schema
}
]
]
])
}