Object Storage: uploadFromStream fails with “Error code undefined” (1MB finalize; ~4MB mid-stream)

Bugs
,
1

Hi folks,
I’m seeing consistent failures with the @replit/object-storage JS SDK when using uploadFromStream.

What’s happening

  • Small streams (e.g., 1 MB) are fully read by the SDK, then fail during finalize with:

    StreamRequestError: Error: Error code undefined

  • Larger streams fail mid-stream around exactly 4 MB processed.

  • Falling back to uploadFromFilename (temp-file path) works reliably on the same data.

This is on a standard Node.js Replit environment using the latest @replit/object-storage. Replit status shows no outage.

Minimal repro

To rule out browser/network issues, I used a synthetic Readable and a byte-counter Transform to confirm how many bytes the SDK consumed before failing:

import { Client } from '@replit/object-storage';
import { Readable, Transform } from 'stream';

async function uploadSynthetic(sizeMB: number) {
  const client = new Client();
  // Bucket init via env as usual (omitted here)
  // await (client as any).init(process.env.REPLIT_OBJECT_STORAGE_BUCKET_ID);

  // 1MB chunk source
  let remaining = sizeMB;
  const src = new Readable({
    read() {
      if (remaining-- <= 0) return this.push(null);
      this.push(Buffer.alloc(1024 * 1024));
    }
  });

  // byte counter
  let seen = 0;
  const tap = new Transform({
    transform(chunk, _enc, cb) { seen += chunk.length; cb(null, chunk); }
  });

  src.pipe(tap);

  try {
    await client.uploadFromStream(
      `debug/stream-${Date.now()}-${sizeMB}MB.bin`,
      tap as any,
      { contentType: 'application/octet-stream', contentLength: String(sizeMB * 1024 * 1024) } as any
    );
    console.log('OK, bytes seen:', seen);
  } catch (e) {
    console.error('FAILED, bytes seen:', seen, 'error:', (e as any)?.message || e);
  }
}

// Examples:
// await uploadSynthetic(1);   // reads 1,048,576 bytes then fails at finalize
// await uploadSynthetic(10);  // fails after 4,194,304 bytes processed

Observed results

  • sizeMB=1 → seen=1048576 (all bytes) → StreamRequestError: Error code undefined

  • sizeMB=10 → seen=4194304 (exactly 4 MB) → same error

  • Stack points into the SDK (e.g., client.ts around the write stream).

Workaround

I’ve implemented a feature flag:

  • OBJECT_STORAGE_STREAMING=false → write stream to /tmp, then call uploadFromFilename → works

  • OBJECT_STORAGE_STREAMING=true → call uploadFromStream → fails as above

Downside: temp files tie upload size to workspace disk and add extra I/O.

Ask

  • Is there a known limitation or required usage pattern for uploadFromStream (chunk sizes, headers, contentLength handling)?

  • Could the SDK be failing on multi-chunk streams (~4 MB boundary)?

Happy to run additional tests or share more logs if helpful. Thanks! :folded_hands:

2

Woke up and replit object storage SDK looks to be working again. So problem solved!

Would be great to have a system status page for object-storage.

3

They did recently change some things, also pushed a huge upgrade overnight.