A Terraform variable serves as a parameter to customize the stack or a module.
const imageId = new TerraformVariable(this, 'imageId', {
type: 'string',
default: 'ami-abcde123',
description: 'What AMI to use to create an instance'
});
new Instance(this, 'hello', {
ami: imageId.value,
instanceType: 't2.micro'
});