sulfite

Overview

sulfite is a high-level S3 client built on AWS SDK for Rust for even better ease of use, reliability, and bandwidth saturation (>50 Gbps).

The name: SO3^2-, an anion, implying a companion to some other cation (application), is commonly used as a preservative in wines and dried fruits (preserve to S3). It's S3 with an O in the middle, a play on oxidization.

Motivation

The AWS SDK is a little low-level for users to take advantage of the concurrency & parallelism, with the following challenges:

1. You need to orchestrate the parallel multipart download & upload for large files.
2. The built-in retry settings are too basic (limited to HTTP status codes, none for bytestream errors), and we allow installing higher-level retries.
3. The async API doesn't agree well with the filesystem for high-throughput operations, when it comes to streaming small chunks from/to disk.

To address them, we provide implementations for the parallel multipart download & upload, and higher-level retries. We also make sure the on-disk file is adequately buffered to avoid async-sync overhead.

Low-level access — S3Client exposes the underlying AWS SDK client as the public inner field so you can call SDK operations not covered by this crate.

Testing

Integration tests use LocalStack for S3.

• Local: Start LocalStack, then run the ignored integration tests:

  docker run --rm -it -p 4566:4566 -e SERVICES=s3 localstack/localstack
  cargo test -p sulfite --test localstack -- --ignored
  

• CI: GitHub Actions runs LocalStack as a service container and runs the same tests (see .github/workflows/ci.yml).