Terraform Go code for generating the instance attachment IDs

Terraform_Instance_Attachment_ID.go

// Update the variables below from the output of your terraform apply, assuming the attachment name is "attachment".
// Then paste this into https://play.golang.org/ and run it.  This example is here https://play.golang.org/p/UgXxMqbdxH
// Copied from the terraform code directly at https://github.com/hashicorp/terraform

// output "attachment_name" {
//  value = "${aws_volume_attachment.attachment.device_name}"
// }

// output "attachment_instance_id" {
//   value = "${aws_volume_attachment.attachment.instance_id}"
// }

// output "attachment_vol_id" {
//   value = "${aws_volume_attachment.attachment.volume_id}"
// }

package main

import (
	"bytes"
	"fmt"
	"hash/crc32"
)

func return_tf_hash(s string) int {
	v := int(crc32.ChecksumIEEE([]byte(s)))
	if v >= 0 {
		return v
	}
	if -v >= 0 {
		return -v
	}
	// v == MinInt
	return 0
}

func volumeAttachmentID(name, volumeID, instanceID string) string {
	var buf bytes.Buffer
	buf.WriteString(fmt.Sprintf("%s-", name))
	buf.WriteString(fmt.Sprintf("%s-", instanceID))
	buf.WriteString(fmt.Sprintf("%s-", volumeID))

	return fmt.Sprintf("vai-%d", return_tf_hash(buf.String()))
}

func main() {
	var name = "sdf"
	var vID = "vol-09692af1265f50676"
	var iID = "i-04e90f372c3653925"
	fmt.Println(volumeAttachmentID(name, vID, iID))
}