serverless-tag-resources/src/tags.js

Datamart: Tag all AWS resources with dual legacy + datamart:* tag support

"use strict";

/**
 * Tag building module.
 *
 * Auto-generates datamart:* tags only (no legacy PascalCase):
 *   - datamart:environment  (from deployment stage)
 *   - datamart:resource     (from CloudFormation LogicalID)
 *
 * Legacy tags (Stage, Resource) removed in v3.1.0 per tagging policy v2.1.
 */

// Tags injected by SFW that should be removed post-deploy
const TAGS_TO_REMOVE = ["STAGE"];

/**
 * Build list-based tags [{Key, Value}] for CloudFormation resources.
 * Merges stackTags + auto-generated datamart:* tags.
 */
function buildListTags(stackTags, stage, logicalId) {
  const tags = [];
  const seen = new Set();

  // User-provided stackTags
  if (stackTags && typeof stackTags === "object") {
    for (const [key, value] of Object.entries(stackTags)) {
      tags.push({ Key: key, Value: String(value) });
      seen.add(key.toLowerCase());
    }
  }

  // Auto-generated datamart:* tags only
  const autoTags = [
    { Key: "datamart:environment", Value: stage },
    { Key: "datamart:resource", Value: logicalId },
  ];

  for (const tag of autoTags) {
    if (!seen.has(tag.Key.toLowerCase())) {
      tags.push(tag);
      seen.add(tag.Key.toLowerCase());
    }
  }

  return tags;
}

/**
 * Build dict-based tags {key: value} for resources that use map format
 * (SSM Parameter, API Gateway V2, Glue, Batch, etc.)
 */
function buildDictTags(stackTags, stage, logicalId) {
  const tags = {};

  // User-provided stackTags
  if (stackTags && typeof stackTags === "object") {
    for (const [key, value] of Object.entries(stackTags)) {
      tags[key] = String(value);
    }
  }

  // Auto-generated datamart:* tags only — don't overwrite user-provided
  if (!tags["datamart:environment"]) tags["datamart:environment"] = stage;
  if (!tags["datamart:resource"]) tags["datamart:resource"] = logicalId;

  return tags;
}

/**
 * Filter out aws: prefixed tags (reserved by AWS, cannot be set by user).
 */
function excludeAwsTags(tags) {
  return tags.filter(
    (tag) => !tag.Key.toLowerCase().startsWith("aws:")
  );
}

module.exports = { buildListTags, buildDictTags, excludeAwsTags, TAGS_TO_REMOVE };