Locals
Locals are used similar to variables, but are not part of a module its interface. They are often used to prevent repetition of values or to hold stateful values.
Locals are declared in the locals block and ideally in a separate locals.tf file.
locals {
retention_days = 60
}
Locals can be referenced in a module using local.<local name>.
Here we’re creating a aws_kms_key and a aws_cloudwatch_log_group that both require a retention argument in days. To prevent maintaining the retention days in separate places we can use a local called e.g. retention_days.
locals {
retention_days = 60
}
resource "aws_kms_key" "example" {
description = "Example KMS key"
deletion_window_in_days = local.retention_days
}
resource "aws_cloudwatch_log_group" "example" {
name = "Example CloudWatch Log Group"
kms_key_id = aws_kms_key.example.arn
retention_in_days = local.retention_days
}
Locals can also be used to store stateful values, think of a local called instance_ids that stores the IDs of all dev and staging instances created.
locals {
instance_ids = concat(aws_instance.dev.*.id, aws_instance.staging.*.id)
}
Want to learn more about Locals? Check out the docs.
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