Generate zone records file (terraform) from AWS Route53 zone dump.

generate_zone_records_from_json.py

"""
Generate zone records file (terraform) from zone dump.
To get zone dump: 
aws route53 list-resource-record-sets --hosted-zone-id ZONE ID > records.json

Example usage:
ZONE_FILE=records.json TERRAFORM_DIR=zone_name python generate_zone_records_from_json.py

Based on:
https://mrkaran.dev/posts/terraform-route53-import/
"""

import json
from os import getenv, path
from string import Template
from subprocess import run
from sys import exit

# terraform resource path of the zone  to add resource to.
ZONE_ID = "aws_route53_zone.main.zone_id"
ZONE_FILE = getenv("ZONE_FILE")
TERRAFORM_DIR = getenv("TERRAFORM_DIR")
RECORDS_FILE_PATH = path.join(TERRAFORM_DIR, "records.tf")


def check_env_vars():
    if not ZONE_FILE:
        return "$ZONE_FILE"
    if not TERRAFORM_DIR:
        return "$TERRAFORM_DIR"
    return ""

# Loads the zone records in a dict


def load_records(zone_file=ZONE_FILE):
    with open(zone_file) as record_file:
        data = json.load(record_file)
    return data


# Creates the Terraform template
def template_records_file(resource_safe_name, resource_name, resource_type, resource_values=None, alias_values=None, resource_ttl=60):
    if resource_values:
        add_records_record = Template(
            """
            resource "aws_route53_record" "$resource_safe_name" {
                zone_id = $zone_id
                name    = "$resource_name"
                type    = "$resource_type"
                ttl     = "$resource_ttl"
                records = $resource_values
            }
        """
        )
    if alias_values:
        add_records_record = Template(
            """
            resource "aws_route53_record" "$resource_safe_name" {
                zone_id = $zone_id
                name    = "$resource_name"
                type    = "$resource_type"
                alias {
                    name                   = "$aliasTarget_DNSName"
                    zone_id                = "$aliasTarget_HostedZoneId"
                    evaluate_target_health = $aliasTarget_EvaluateTargetHealth
                }
            }
        """
        )
    with open(RECORDS_FILE_PATH, "a") as f:
        f.write(add_records_record.safe_substitute(
            zone_id=ZONE_ID,
            resource_name=resource_name,
            resource_safe_name=resource_safe_name,
            resource_type=resource_type,
            resource_ttl=resource_ttl,
            resource_values=resource_values,
            aliasTarget_DNSName=alias_values.get("DNSName"),
            aliasTarget_HostedZoneId=alias_values.get("HostedZoneId"),
            aliasTarget_EvaluateTargetHealth="true" if alias_values.get(
                "EvaluateTargetHealth") else "false"
        ))


if __name__ == "__main__":
    missing = check_env_vars()
    if missing:
        exit(f"Required env variable {missing} is missing.")
    with open(RECORDS_FILE_PATH, "w") as f:
        # just clear the file
        pass
    records = load_records()
    for i in records.get("ResourceRecordSets"):
        resource_name = i.get("Name")
        resource_type = i.get("Type")
        resource_safe_name = resource_name.replace(".", "__")[:-2]
        resource_safe_name = f"{resource_type}_{resource_safe_name}"
        resource_ttl = i.get("TTL")
        alias_values = i.get("AliasTarget", {})
        resource_values = json.dumps(
            [record.get("Value").replace("\"", "") for record in i.get("ResourceRecords", [])])
        template_records_file(resource_safe_name, resource_name,
                              resource_type, resource_values, alias_values, resource_ttl)
        print(f"Imported {resource_name} {resource_type}")