Error when uploading to Cloudflare R2

[avsaase]

I set up this integration yesterday to upload my backups to Cloudflare R2 and when it first ran last night it encountered an error:

Logger: homeassistant.components.backup
Bron: components/backup/manager.py:585
integratie: Backup (documentatie, problemen)
Eerst voorgekomen: 04:45:51 (1 gebeurtenis)
Laatst gelogd: 04:45:51

Unexpected error for bauergroup_s3compatiblebackup.01KEN0V36KESZB2ZBW1XD6HX26: An error occurred (InvalidPart) when calling the CompleteMultipartUpload operation: All non-trailing parts must have the same length.
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/components/backup/manager.py", line 585, in upload_backup_to_agent
    await self.backup_agents[agent_id].async_upload_backup(
    ...<2 lines>...
    )
  File "/config/custom_components/bauergroup_s3compatiblebackup/backup.py", line 176, in async_upload_backup
    await self._upload_multipart(tar_key, open_stream)
  File "/config/custom_components/bauergroup_s3compatiblebackup/backup.py", line 271, in _upload_multipart
    await self._client.complete_multipart_upload(
    ...<4 lines>...
    )
  File "/usr/local/lib/python3.13/site-packages/aiobotocore/client.py", line 412, in _make_api_call
    raise error_class(parsed_response, operation_name)
botocore.exceptions.ClientError: An error occurred (InvalidPart) when calling the CompleteMultipartUpload operation: All non-trailing parts must have the same length.

I haven't tested with other S3 providers so I don't know if they work correctly but the error doesn't sound S2 specific.

[karlspace]

Thank you for reporting this! This issue has been identified and fixed.

Problem

The multipart upload was sending parts with variable sizes (e.g., 20.5 MiB, 21.3 MiB, 19.8 MiB) depending on when the buffer exceeded the minimum threshold. While AWS S3 and most providers are tolerant of this, Cloudflare R2 strictly require all non-trailing parts to have exactly the same size.

Error message:
InvalidPart: All non-trailing parts must have the same length

Solution

Fixed in v0.1.3 - The multipart upload now sends all non-final parts with exactly 20 MiB:

Before: Part 1: 20.5 MiB | Part 2: 21.3 MiB | Part 3: 18.3 MiB ❌
After: Part 1: 20.0 MiB | Part 2: 20.0 MiB | Part 3: 10.0 MiB ✅

How to Update

HACS:

1. Go to HACS → Integrations
2. Find "BAUERGROUP - S3 Compatible Backup"
3. Click Update (or reinstall if update not shown)
4. Restart Home Assistant

Manual:

cd /config/custom_components/bauergroup_s3compatiblebackup
git pull
Then restart Home Assistant.

This fix improves compatibility with stricter S3-compatible providers while maintaining full compatibility with AWS S3, MinIO, Wasabi, Backblaze B2, DigitalOcean Spaces, and others.