Object Storage Client

One URL-based API for AWS S3, Google Cloud Storage, Azure Blob Storage, HTTP(S) and the local filesystem, as a Rust library, Python bindings and the osc command-line tool. The scheme of each URL picks the backend, so a single client can copy and move objects between providers, stream large objects in bounded memory and generate pre-signed URLs. Optional client-side encryption keeps object contents hidden from the storage provider.

• One API for every backend, including cross-provider copy and move.
• Streaming uploads and downloads, with multipart uploads for large objects.
• Listing of a prefix or a whole bucket (flat and recursive), existence checks and bucket creation.
• Pre-signed URLs for S3, GCS and Azure.
• Client-side encryption (Cargo feature encryption, on by default) with self-reloading keyrings and key rotation.

For the cloud schemes the host is the bucket or container and the path is the object key. A bucket-root URL such as s3://bucket addresses the bucket itself: list it, create it or check that it exists. Credentials come from environment variables; see Configuration.

Rust

The crate is published to the Bixority Codeberg crate registry:

export CARGO_REGISTRIES_BIXORITY_INDEX="sparse+https://codeberg.org/api/packages/bixority/cargo/"

[dependencies]
object-storage-client = { version = "0.2", registry = "bixority" }
# or: object-storage-client = { git = "https://codeberg.org/bixority/object-storage-client" }
tokio = { version = "1", features = ["full"] }

The encryption and cli features are on by default. A library that does not need the CLI can drop clap and tokio-util:

object-storage-client = { version = "0.2", registry = "bixority", default-features = false, features = ["encryption"] }

use object_storage_client::{ObjectStorageClient, SignMethod, SignOptions};
use std::time::Duration;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let client = ObjectStorageClient::new();

    // Create a bucket (S3/GCS/Azure, or a directory for file:// URLs); idempotent
    client.create_bucket("s3://my-bucket").await?;

    // Upload data to S3
    client.put("s3://my-bucket/hello.txt", &b"Hello from Rust!"[..]).await?;

    // Download it back
    let retrieved = client.get("s3://my-bucket/hello.txt").await?;
    println!("Retrieved: {}", String::from_utf8_lossy(&retrieved));

    // List the whole bucket from a bucket-root URL (flat, recursive: every key
    // is returned). Pass a prefix such as "s3://my-bucket/logs/" to narrow it.
    let keys = client.list("s3://my-bucket").await?;
    println!("Bucket keys: {keys:?}");

    // Existence checks (missing -> Ok(false), never an error)
    if client.bucket_exists("s3://my-bucket").await? {
        println!("my-bucket is present");
    }
    if client.exists("s3://my-bucket/hello.txt").await? {
        println!("hello.txt is present");
    }

    // --- Move data across providers with one client ---

    // Copy S3 -> Google Cloud Storage (source is left in place)
    client
        .copy("s3://my-bucket/hello.txt", "gs://my-gcs-bucket/hello.txt")
        .await?;

    // Move GCS -> Azure Blob Storage (source is deleted afterwards)
    client
        .move_object("gs://my-gcs-bucket/hello.txt", "az://my-container/hello.txt")
        .await?;

    // Copy Azure -> local disk for a working copy
    client
        .copy("az://my-container/hello.txt", "file:///tmp/hello_local.txt")
        .await?;

    // --- Pre-signed URLs: time-limited, credential-free access (S3/GCS/Azure) ---

    // Pre-signed download (GET) link, valid for one hour
    let download_url = client
        .get_pre_signed_url(
            "s3://my-bucket/hello.txt",
            SignMethod::Get,
            Duration::from_secs(3600),
            &SignOptions::default(),
        )
        .await?;
    println!("Share this download link: {download_url}");

    // Pre-signed upload (PUT) link binding the exact size and type the client
    // must send (S3 only); the store rejects mismatched uploads up front.
    let upload_url = client
        .get_pre_signed_url(
            "s3://my-bucket/upload.bin",
            SignMethod::Put,
            Duration::from_secs(900),
            &SignOptions {
                content_length: Some(1_048_576),
                content_type: Some("application/octet-stream".to_string()),
            },
        )
        .await?;
    println!("Upload directly to: {upload_url}");

    Ok(())
}

With encryption, the same calls on an encrypting view:

use object_storage_client::encryption::{EncryptionConfig, Keyring};
use object_storage_client::ObjectStorageClient;
use std::sync::Arc;

let keyring = Arc::new(Keyring::from_file("/var/run/secrets/osc/keyring")?); // reloads itself
let secure = ObjectStorageClient::new().with_encryption(EncryptionConfig::new(keyring.clone()));

secure.put("s3://my-bucket/payroll.csv", &b"id,salary"[..]).await?; // only ciphertext is stored
let csv = secure.get("s3://my-bucket/payroll.csv").await?;          // authenticated before it is returned
let health = keyring.status(); // active key, key ages, last reload error

Python

The package is published on PyPI and needs Python 3.13+:

pip install object-storage-client

import asyncio
from object_storage_client import ObjectStorageClient

async def main():
    client = ObjectStorageClient()

    # Create a bucket (S3/GCS/Azure, or a directory for file:// URLs); idempotent
    await client.create_bucket("s3://my-bucket")

    # Check whether a bucket exists (returns a bool; never raises for a miss).
    if await client.bucket_exists("s3://my-bucket"):
        print("my-bucket is present")

    # Upload data to S3
    await client.put_object("s3://my-bucket/hello.txt", b"Hello from Python!")

    # Check whether an object exists (returns a bool; never raises for a miss).
    # If you prefer the missing case to raise FileNotFoundError, use
    # get_object_metadata() or get_object() instead.
    if await client.object_exists("s3://my-bucket/hello.txt"):
        print("hello.txt is present")

    # Fetch full metadata (raises FileNotFoundError if the object is missing)
    meta = await client.get_object_metadata("s3://my-bucket/hello.txt")
    print(f"Size: {meta['size_bytes']}, type: {meta['content_type']}")

    # Download data
    data = await client.get_object("s3://my-bucket/hello.txt")
    print(f"Retrieved: {data.decode()}")

    # List objects
    items = await client.list_objects("s3://my-bucket/")
    print(f"Bucket items: {items}")

    # Stream data
    stream = await client.get_object_stream("s3://my-bucket/hello.txt")
    async for chunk in stream:
        print(f"Chunk size: {len(chunk)}")

    # --- Move data across providers with one client ---

    # Copy S3 -> Google Cloud Storage (source is left in place)
    await client.copy_object("s3://my-bucket/hello.txt", "gs://my-gcs-bucket/hello.txt")

    # Move GCS -> Azure Blob Storage (source is deleted afterwards)
    await client.move_object("gs://my-gcs-bucket/hello.txt", "az://my-container/hello.txt")

    # Copy Azure -> local disk for a working copy
    await client.copy_object("az://my-container/hello.txt", "file:///tmp/hello_local.txt")

    # --- Pre-signed URLs (S3/GCS/Azure): credential-free, time-limited access ---

    download_url = await client.get_pre_signed_url("s3://my-bucket/hello.txt")
    # Bind the exact Content-Length and Content-Type the client must send (S3
    # only); the store rejects uploads that don't match.
    upload_url = await client.get_pre_signed_url(
        "s3://my-bucket/upload.bin",
        method="PUT",
        expires_in_secs=900,
        content_length=1_048_576,
        content_type="application/octet-stream",
    )
    print(f"Download: {download_url}\nUpload: {upload_url}")

if __name__ == "__main__":
    asyncio.run(main())

With encryption (key bytes never reach Python):

from object_storage_client import ObjectStorageClient, Keyring

keyring = Keyring.from_file("/var/run/secrets/osc/keyring")    # reloads itself
secure = ObjectStorageClient().with_encryption(keyring)

await secure.put_object("s3://my-bucket/payroll.csv", b"id,salary")  # only ciphertext is stored
data = await secure.get_object("s3://my-bucket/payroll.csv")         # authenticated before it is returned
health = keyring.status()  # active key, key ages, last reload error

CLI (osc)

export CARGO_REGISTRIES_BIXORITY_INDEX="sparse+https://codeberg.org/api/packages/bixority/cargo/"
cargo install object-storage-client --registry bixority
# or: cargo install --git https://codeberg.org/bixority/object-storage-client
# or, from a checkout: cargo install --path .

osc put my_file.txt s3://my-bucket/remote_file.txt              # upload a file
osc put --recursive my_dir s3://my-bucket/remote_dir/           # upload a directory
osc get gs://my-bucket/data.json ./local_data.json              # download
osc get-stream gs://my-bucket/large_file.bin > large_file.bin   # stream to stdout; progress on stderr
osc cp s3://source-bucket/image.png az://dest-container/image.png   # copy between providers
osc mv s3://my-bucket/old_name.txt s3://my-bucket/new_name.txt
osc ls s3://my-bucket/logs/
osc rm s3://my-bucket/temp_file.tmp
osc exists s3://my-bucket/report.pdf                            # prints true or false
osc mb s3://my-new-bucket                                       # create a bucket (a directory for local paths)
osc bucket-exists s3://my-bucket                                # prints true or false

# Pre-signed URLs (S3, GCS, Azure): a download link valid for the default
# 1 hour, and an upload (PUT) link valid for 15 minutes
osc sign s3://my-bucket/report.pdf
osc sign --method PUT --expires-in 900 s3://my-bucket/upload.bin
# S3 only: the upload is rejected unless Content-Length and Content-Type match
osc sign --method PUT --content-length 1048576 \
    --content-type application/pdf s3://my-bucket/upload.pdf

With a keyring, put, get, get-stream, cp and mv encrypt and decrypt transparently:

umask 077                                    # keyring files must not be readable by others
osc keyring new > keyring                    # a keyring with one fresh key
osc --keyring keyring put report.csv s3://my-bucket/report.csv
osc --keyring keyring get s3://my-bucket/report.csv report.csv
osc enc inspect s3://my-bucket/report.csv    # header details; no keys needed

# Rotation: add a new active key, then move objects off the old one
osc keyring rotate < keyring > keyring.new && mv keyring.new keyring
osc --keyring keyring enc reencrypt s3://my-bucket/ --from <old key ID>

--keyring can also come from OSC_KEYRING_FILE, or from a command that prints the keyring (OSC_KEYRING_COMMAND), so the keyring never touches the disk.

Documentation

• Configuration: credentials and environment variables for each provider.
• Encryption: what it protects, keyrings, Kubernetes, key rotation, responding to a key leak, the format and interop.
• Behaviour and limits: URL rules, copy and move, deletes, file permissions, large objects, pre-signing, CLI and Python details.
• Upgrading: breaking changes in 0.2.0.
• Development and Testing.