This is a shell script that may be used to acquire the time from now using Terraform's External provider

date_from_now_terraform.sh

#!/bin/sh

# Terraform's External provider:
# https://www.terraform.io/docs/providers/external/data_source.html
#
# Sample usage (Terraform):
# data "external" "nextmonth" {
#   program = ["sh", "${path.module}date_from_now_terraform.sh"]
#
#   query = {   
#     date = "next month"
#   }
# }
#
# ... "${data.nextmonth.result.date}" ...
#
# Sample usage (shell):
#
# jq -n "{\"query\":{\"date\":\"next month\"}}" | sh ./date_from_now_terraform.sh 
#
# Sample output:
# {
#   "result": {
#     "date": "2020-12-07"
#   }
# }

jq -n "{\"result\":{\"date\":\"$(date -d "$(jq -r ".query.date")" +%Y-%m-%d)\"}}"