Example terraform output using a module

main.tf

# Call the module
module "vpc" {
    source = "../modules/foo/bar/baz"

    environment_name = "${var.environment_name}"
    vpc_cidr = "${var.vpc_cidr}"
    vpc_instance_tenancy = "dedicated"
    vpc_enable_dns_support = true
    vpc_enable_dns_hostnames = true
    zones = "${var.zones}"
    public_subnet_cidrs = "${var.public_subnet_cidrs}"
    private_subnet_cidrs = "${var.private_subnet_cidrs}"
}

# Define outputs for this main.tf file.
# Note that if we want to output values from the vpc module
# call, then we need to define those explicitly
output "public_subnet_ids" {
    value = "${module.vpc.public_subnet_ids}"
}

output "private_subnet_ids" {
    value = "${module.vpc.private_subnet_ids}"
}