fix: billing extract tags lowercase props (#321)

Update the billing extract tags Lambda function so that it outputs the
property keys as lowercase.  This will cause the written JSON file properties to match
the AWS Glue schema that gets created when the file is crawled.

terragrunt/org_account/cost_usage_report/lambdas/billing_extract_tags/main.py

@@ -3,6 +3,7 @@
 This is then used to enrich the billing data with the account tags to allow
 for business unit filtering.
 """
+
 import json
 import logging
 import os
@@ -61,11 +62,26 @@ def handler(event, context):
 
     # .write json to string and add a newline between each record
     logging.info("Writing account tags to json")
-    accounts = json.dumps(accounts, default=str, indent=2)
-    logging.info(f"Accounts: {accounts}")
+    accounts_json = (
+        "[\n"
+        + ",\n".join(
+            json.dumps(
+                {k.lower(): v for k, v in account.items()},
+                default=str,
+                separators=(",", ": "),
+            )
+            for account in accounts
+        )
+        + "\n]"
+    )
+    logging.info(f"Accounts: {accounts_json}")
 
     # save accounts to an s3 bucket
     logging.info("Saving account tags to s3")
-    s3.put_object(Bucket=TARGET_BUCKET, Key="operations/aws/organization/account-tags.json", Body=accounts)
+    s3.put_object(
+        Bucket=TARGET_BUCKET,
+        Key="operations/aws/organization/account-tags.json",
+        Body=accounts_json,
+    )
 
     return {"statusCode": 200}

terragrunt/org_account/cost_usage_report/lambdas/billing_extract_tags/test_main.py

@@ -3,7 +3,7 @@
 from main import handler
 
 TARGET_BUCKET = "TARGET_BUCKET"
-ACCOUNT_TAGS_KEY = "account_tags.json"
+ACCOUNT_TAGS_KEY = "operations/aws/organization/account-tags.json"
 
 
 class TestLambdaHandler(unittest.TestCase):
@@ -31,7 +31,8 @@ def test_lambda_handler(
             Bucket=TARGET_BUCKET,
             Key=ACCOUNT_TAGS_KEY,
             Body="""[
-{"Id": "123", "tag_Name": "Dev"}]""",
+{"id": "123","tag_name": "Dev"}
+]""",
         )
 
         self.assertEqual(response, {"statusCode": 200})
@@ -61,6 +62,7 @@ def test_lambda_handler_pagination(
             Bucket=TARGET_BUCKET,
             Key=ACCOUNT_TAGS_KEY,
             Body="""[
-{"Id": "123", "tag_Name": "Dev"},
-{"Id": "456", "tag_Name": "Prod"}]""",
+{"id": "123","tag_name": "Dev"},
+{"id": "456","tag_name": "Prod"}
+]""",
         )