sigv4-s3

Minimal AWS Signature Version 4 (SigV4) client for S3 and S3-compatible object storage such as AWS S3, MinIO, Backblaze B2, and Cloudflare R2.

Why this exists

The official AWS Go SDK v2 is large and brings in dozens of transitive dependencies. If your application only needs basic object operations (PUT, GET, DELETE, COPY) with streaming uploads, sigv4-s3 provides a lightweight client using only the Go standard library.

Features

• Standard library only (crypto/*, net/http, encoding/*)
• Streaming uploads by hashing payload data via io.ReadSeeker without loading entire files into memory
• Daily SigV4 derived key caching to avoid redundant HMAC calculations
• SSE-C header formatting for customer-managed encryption keys
• Path-style (MinIO) and virtual-hosted bucket addressing
• Retries with backoff and stream rewind on transient HTTP 429 and 5xx responses

Installation

go get github.com/fumbledlol/sigv4-s3

Quick start

package main

import (
	"context"
	"os"

	"github.com/fumbledlol/sigv4-s3"
)

func main() {
	client, err := sigv4s3.New(sigv4s3.Config{
		Endpoint:  "https://s3.us-east-1.amazonaws.com",
		Region:    "us-east-1",
		Bucket:    "my-bucket",
		AccessKey: os.Getenv("AWS_ACCESS_KEY_ID"),
		SecretKey: os.Getenv("AWS_SECRET_ACCESS_KEY"),
	})
	if err != nil {
		panic(err)
	}

	ctx := context.Background()

	// Upload file
	file, err := os.Open("avatar.png")
	if err != nil {
		panic(err)
	}
	defer file.Close()

	err = client.PutObject(ctx, "users/1/avatar.png", file, "image/png", nil)
	if err != nil {
		panic(err)
	}

	// Copy object
	err = client.CopyObject(ctx, "users/1/avatar.png", "users/1/avatar-backup.png", nil)
	if err != nil {
		panic(err)
	}

	// Delete object
	err = client.DeleteObject(ctx, "users/1/avatar.png")
	if err != nil {
		panic(err)
	}
}

Benchmarks

BenchmarkAuthorize-12    454682    2785 ns/op    2848 B/op    25 allocs/op

License

MIT