feat: add management command to clean up unreferenced bucket objects

document_merge_service/api/management/commands/clean_dangling_objects.py

@@ -0,0 +1,82 @@
+import boto3
+import botocore
+from django.conf import settings
+from django.core.management.base import BaseCommand
+from document_merge_service.api.models import Template
+
+
+S3_ENDPOINT_URL = settings.S3_STORAGE_OPTIONS["endpoint_url"]
+S3_ACCESS_KEY_ID = settings.S3_STORAGE_OPTIONS["access_key"]
+S3_SECRET_ACCESS_KEY = settings.S3_STORAGE_OPTIONS["secret_key"]
+S3_BUCKET = settings.S3_STORAGE_OPTIONS["bucket_name"]
+
+
+class Command(BaseCommand):
+    help = "Cleans up unreferenced files and warns about unencrypted files in the storage bucket"
+
+    def get_object_keys(self, s3_client):
+        keys = []
+        have_next = True
+        continuation_token = None
+        while have_next:
+            data = s3_client.list_objects_v2(
+                Bucket=S3_BUCKET,
+                **(
+                    {"ContinuationToken": continuation_token}
+                    if continuation_token
+                    else {}
+                ),
+            )
+            if data["KeyCount"] > 0:
+                keys += [o["Key"] for o in data["Contents"]]
+            have_next = data["IsTruncated"]
+            if have_next:
+                continuation_token = data["NextContinuationToken"]
+        return keys
+
+    def delete_file(self, s3_client, stats: dict, fname: str):
+        print(f"Deleting unreferenced file: {fname}")
+        # TODO: delete for real
+        # s3_client.delete_object(Bucket=S3_BUCKET, Key=fname)
+        stats["deleted"] += 1
+
+    def check_encryption(self, s3_client, stats: dict, fname: str):
+        # Our approach is rather unsophisticated: we try to download an object
+        # without encryption key, and if that succeeds, it means the object is
+        # not encrypted, and therefore we print a warning.
+        try:
+            s3_client.get_object(Bucket=mapping["s3_bucket"], Key=fname)
+            print(f"WARNING, unencrypted file: {fname}")
+            stats["unencrypted"] += 1
+        except botocore.exceptions.ClientError:
+            stats["encrypted"] += 1
+
+    def handle(self, *args, **options):
+        s3_session = boto3.session.Session()
+        s3_client = s3_session.client(
+            service_name="s3",
+            aws_access_key_id=S3_ACCESS_KEY_ID,
+            aws_secret_access_key=S3_SECRET_ACCESS_KEY,
+            endpoint_url=S3_ENDPOINT_URL,
+        )
+        bucket_files = self.get_object_keys(s3_client)
+        used_files = [t.template.path for t in Template.objects.all()]
+
+        print(
+            f"Cleaning up among {len(bucket_files)} bucket objects and {len(used_files)} DB entries"
+        )
+        stats = {
+            "total": len(bucket_files),
+            "encrypted": 0,
+            "unencrypted": 0,
+            "deleted": 0,
+        }
+        for f in bucket_files:
+            if f in used_files:
+                # file found in db, check if it's encrypted
+                self.check_encryption(s3_client, stats, f)
+            else:
+                # file not found in db, can be deleted
+                self.delete_file(s3_client, stats, f)
+
+        print(f"stats: {stats}")