Generates Terraform Import Commands for v4 AWS S3 Bucket Configuration Changes

importS3Resources.js

const fs = require("fs");

const rawData = fs.readFileSync("plan.json");

const data = JSON.parse(rawData);

const changes = data.resource_changes.filter(
  (c) =>
    c.change.actions.indexOf("create") !== -1 &&
    c.type.startsWith("aws_s3_bucket_")
);

const lines = changes.map((c) => {
  let base = `terraform import ${c.address} ${c.change.after.bucket}`;

  if (c.type === "aws_s3_bucket_acl") {
    base = `${base},${c.change.after.acl}`;
  }

  return base;
});

console.log(lines.join("\n"));

This little script is helpful when upgrading the Terraform AWS provider from v3 to v4, which introduced significant changes to the AWS S3 bucket configuration that, I believe, requires importing existing resources to the new resources.

Assumes that a plan.json file has first been generated in the same directory as this script by running:

terraform plan -out "tfplan"
terraform show -json "tfplan" > plan.json

Running:

node importS3Resources.js

will not actually import any Terraform resources, but will produce a series of terraform import ... commands that can be used in a script to import all resources, e.g.:

terraform import aws_s3_bucket_acl.example example-bucket,private
terraform import aws_s3_bucket_server_side_encryption_configuration.example example-bucket

Variation for moving Route53 zone to a different account:

const fs = require("fs");

const rawData = fs.readFileSync("plan.json");

const data = JSON.parse(rawData);

const changes = data.resource_changes.filter(
  (c) =>
    c.change.actions.indexOf("create") !== -1 && c.type === "aws_route53_record"
);

const lines = changes.map((c) => {
  const { zone_id, name, type } = c.change.after;
  let base = `terraform import ${c.address} ${zone_id}_${name}_${type}`;
  return base;
});

console.log(lines.join("\n"));