putting security group ids of a vpc in a list using terraform

Question

While trying to create vpc endpoint , i have to dynamically create the security groups within the vpc and then attach it to the vpc endpoints in the same terraform plan . Is there a way I can put all the security group ids of a VPC in a list using terraform?

Answer 1

Is there a way I can put all the security group ids of a VPC in a list using terraform?

Yes, you can use aws_security_groups data source:

data "aws_security_groups" "test" {
  filter {
    name   = "vpc-id"
    values = ["your-vpc-id"]
  }
}

output "test" {
  value = data.aws_security_groups.test.ids
}

Answer 2

create the vpc as shown below

resource "aws_vpc" "main" {
id = var.vpc_id
cidr_block = "10.0.0.0/16"
}

create the security group

resource "aws_security_group" "sg1" {
name        = "allow_tls"
description = "Allow TLS inbound traffic"
vpc_id      = aws_vpc.main.id

ingress {
description      = "TLS from VPC"
from_port        = 443
to_port          = 443
protocol         = "tcp"
cidr_blocks      = [aws_vpc.main.cidr_block]
ipv6_cidr_blocks = [aws_vpc.main.ipv6_cidr_block]
}

egress {
from_port        = 0
to_port          = 0
protocol         = "-1"
cidr_blocks      = ["0.0.0.0/0"]
ipv6_cidr_blocks = ["::/0"]
}

tags = {
Name = "allow_tls"
}
}

creating vpc endpoint fetching security group ID's dynamically from the above security group resource block

resource "aws_vpc_endpoint" "endpoint_vpc" {
vpc_id            = aws_vpc.main.id
service_name      = "com.amazonaws.us-west-2.ec2"
vpc_endpoint_type = "Interface"

security_group_ids = [
aws_security_group.sg1.id,
]

private_dns_enabled = true
}

you can always get the results in outputs.tf file like mentioned below

output "security_groups_id's" {
value = aws_security_groups.sg1.ids
}