Terraform dynamic loop to create multiple dynamodb - amazon-web-services

Question

I'm trying to create a dynamic method to create multiple dynamodb tables with their own attributes. I tried for loops with dynamic blocks, list objects, etc but was not able to iterate attributes for each table. The goal is to have multiple tables with different attributes and global indexes for each table in one go. I have terraform.tfvars and main.tf with the following structure:
Variable declaration:
variable "dynamodb_table" {
type = list(object({
table_name = string
billing_mode = string
read_capacity = optional(number)
write_capacity = optional(string)
hash_key = string
ttl_attribute_name = string
ttl_enabled = string
range_key = optional(string)
attribute = object({
name = string
type = string
})
}))
}
variable "global_secondary_indexes" {
description = "Describe a GSI for the table; subject to the normal limits on the number of GSIs, projected attributes, etc."
type = list(object({
index_name = string
index_projection_type = string
index_range_key = string
index_hash_key = string
index_write_capacity = optional(string)
index_read_capacity = optional(string)
index_non_key_attributes = list(string)
}))
default = []
}
dynamodb_table = [
{
table_name = "devops-test-01",
billing_mode = "PAY_PER_REQUEST",
hash_key = "UserId",
range_key = "GameTitle",
ttl_attribute_name = "ttl_attribute_name",
ttl_enabled = "false"
attribute = [
{
name = "UserId"
type = "S"
},
{
name = "GameTitle"
type = "S"
}
]
},
{
table_name = "devops-test-02",
billing_mode = "PAY_PER_REQUEST",
hash_key = "GameTitle",
ttl_attribute_name = "ttl_attribute_name",
ttl_enabled = "false"
}
]
global_secondary_indexes = [
{
index_name = "TitleIndex"
index_hash_key = "UserId"
index_range_key = "GameTitle"
index_projection_type = "INCLUDE"
index_non_key_attributes = ["Id"]
}
]
default_tags = {
"Environment" = "Dev",
"Owner" = "xxx"
}
resource "aws_dynamodb_table" "basic-dynamodb-table" {
for_each = { for key, value in var.dynamodb_table : key => value }
name = each.value.table_name
billing_mode = each.value.billing_mode
read_capacity = each.value.read_capacity
write_capacity = each.value.write_capacity
hash_key = each.value.hash_key
range_key = each.value.range_key
ttl {
attribute_name = each.value.ttl_attribute_name
enabled = each.value.ttl_enabled
}
dynamic "attribute" {
for_each = { for key, value in var.attributes : key => value }
content {
name = attribute.value.name
type = attribute.value.type
}
}
dynamic "global_secondary_index" {
for_each = var.global_secondary_indexes
content {
name = global_secondary_index.value.index_name
hash_key = global_secondary_index.value.index_hash_key
projection_type = global_secondary_index.value.index_projection_type
range_key = lookup(global_secondary_index.value, "index_range_key", null)
read_capacity = lookup(global_secondary_index.value, "index_read_capacity", null)
write_capacity = lookup(global_secondary_index.value, "index_write_capacity", null)
non_key_attributes = lookup(global_secondary_index.value, "index_non_key_attributes", null)
}
}
tags = merge(
var.default_tags,
{
Name = each.value.table_name
})
}
This code produces the following error:
The given value is not suitable for var.dynamodb_table declared at variable.tf:6,1-26: element 0: attribute │ "attribute": object required

Answer 1

You did not share your attributes variable but I have used attributes in dynamodb_table variable.
Your main problem is attribute property in dynamodb_table variable is requeired but you did not provide any value for it in devops-test-02 table values.
variables.tf
variable "dynamodb_table" {
type = list(object({
table_name = string
billing_mode = string
// read_capacity = optional(number)
//write_capacity = optional(string)
hash_key = string
ttl_attribute_name = string
ttl_enabled = string
//range_key = optional(string)
attribute = list(object({
name = string
type = string
}))
}))
default = [
{
table_name = "devops-test-01",
billing_mode = "PAY_PER_REQUEST",
hash_key = "UserId",
range_key = "GameTitle",
ttl_attribute_name = "ttl_attribute_name",
ttl_enabled = "false"
attribute = [
{
name = "UserId"
type = "S"
},
{
name = "GameTitle"
type = "S"
}
]
},
{
table_name = "devops-test-02",
billing_mode = "PAY_PER_REQUEST",
hash_key = "GameTitle",
ttl_attribute_name = "ttl_attribute_name",
ttl_enabled = "false"
attribute = [
{
name = "UserId"
type = "S"
},
{
name = "GameTitle"
type = "S"
}
]
}
]
}
variable "global_secondary_indexes" {
description = "Describe a GSI for the table; subject to the normal limits on the number of GSIs, projected attributes, etc."
type = list(object({
index_name = string
index_projection_type = string
index_range_key = string
index_hash_key = string
//index_write_capacity = optional(string)
//index_read_capacity = optional(string)
index_non_key_attributes = list(string)
}))
default = [
{
index_name = "TitleIndex"
index_hash_key = "UserId"
index_range_key = "GameTitle"
index_projection_type = "INCLUDE"
index_non_key_attributes = ["Id"]
}
]
}
variable "default_tags" {
default = {
"Environment" = "Dev",
"Owner" = "xxx"
}
}
dynamodb.tf
resource "aws_dynamodb_table" "basic-dynamodb-table" {
for_each = { for key, value in var.dynamodb_table : value.table_name => value }
name = each.value.table_name
billing_mode = each.value.billing_mode
read_capacity = lookup(each.value, "read_capacity", null)
write_capacity = lookup(each.value, "write_capacity", null)
hash_key = each.value.hash_key
range_key = lookup(each.value, "range_key", null)
ttl {
attribute_name = each.value.ttl_attribute_name
enabled = each.value.ttl_enabled
}
dynamic "attribute" {
for_each = { for key, value in each.value.attribute : key => value }
content {
name = attribute.value.name
type = attribute.value.type
}
}
dynamic "global_secondary_index" {
for_each = var.global_secondary_indexes
content {
name = global_secondary_index.value.index_name
hash_key = global_secondary_index.value.index_hash_key
projection_type = global_secondary_index.value.index_projection_type
range_key = lookup(global_secondary_index.value, "index_range_key", null)
read_capacity = lookup(global_secondary_index.value, "index_read_capacity", null)
write_capacity = lookup(global_secondary_index.value, "index_write_capacity", null)
non_key_attributes = lookup(global_secondary_index.value, "index_non_key_attributes", null)
}
}
tags = merge(
var.default_tags,
{
Name = each.value.table_name
})
}
UPDATE 2023-01-17
Add Kinesis streaming destination resource to dynamodb tables.
resource "aws_kinesis_stream" "example" {
for_each = aws_dynamodb_table.basic-dynamodb-table
name = "${each.key}_table_stream"
shard_count = 1
}
resource "aws_dynamodb_kinesis_streaming_destination" "example" {
for_each = aws_dynamodb_table.basic-dynamodb-table
stream_arn = aws_kinesis_stream.example[each.key].arn
table_name = each.key
}