Use Random Integer in terraform module

Hi there!

Today, we will learn how to use a random integer generator in terraform module.

Situation -

You are writing a module which takes a url as variable but needs to add a random userId (or any other thing) to the url. How do you achieve this in your terraform module?

Pre-requisites

This post is NOT covering basics of terraform and module writing so some understanding of terraform is expected.
It is assumed that you have terraform setup on your system and have an idea about how to write module.

Steps

• Example module

Consider following datadog synthetics module

resource "datadog_synthetics_test" "test_template" {
    name = var.name
    request_definition {
        method = var.request_method
        url = var.start_url
    }
    // rest of the module
}

The above is a sample for creating a synthetic monitoring test on datadog.
Assume you want to append a parameter userId with random 6 digit number to the url.

• Add random_integer resource

Add a resource for random integer

resource "random_integer" "random_user_id" {
    max = 999999
    min = 100000

    keepers = {
        test_name = var.name
    }

The documentation for random integer.

The above resource generates a 6-digit integer between 100000 and 999999. The keepers field make sure that a new random number is generated each time a new var.name is passed to module.

• Link random_integer resource to the example module

update the url field to

url = "${var.start_url}/${random_integer.random_user_id.result}"

• Checking

Use your module as usual and verify.

That's all!