Depend on a source directory for terraform deployments

lambda.tf

data "external" "lambda_source_trigger" {
    program = ["${path.module}/gethash.sh"]
    
    query = {
        directory = "${path.module}/lambdas/mylambda"
    }
}

resource "null_resource" "deploy_lambda" {
    triggers = {
        go_source_hash = "${data.external.lambda_source_trigger.result["checksum"]}"
    }
    
    provisioner "local-exec" {
        # Your deploy code
    }
}