haybarn-rust

haybarn is an ergonomic Rust wrapper for Haybarn — an independent derived distribution of DuckDB, published by Query Farm LLC. It is a rebrand of the upstream duckdb-rs crate and is intentionally ABI-compatible with DuckDB: the C API, the duckdb:: C++ namespace, headers, and the DUCKDB_VERSION are all preserved. The only differences are the published crate names and the embedded extension trust root.

You can use it to:

• Query Haybarn with type-safe bindings and an API inspired by rusqlite.
• Read and write Arrow, Parquet, JSON, and CSV formats natively.
• Build Haybarn extensions in Rust with custom scalar and table functions.

Crates

Crate	Replaces	Purpose
haybarn	duckdb	ergonomic wrapper
libhaybarn-sys	libduckdb-sys	low-level C-API FFI
haybarn-loadable-macros	duckdb-loadable-macros	extension proc-macros

Versioning follows upstream: the crate version encodes the engine version as 1.MAJOR_MINOR_PATCH.x, so 1.10503.x corresponds to the 1.5.3 engine.

Quickstart

Add the haybarn crate with the bundled feature. bundled is the supported path for Haybarn — it compiles the Haybarn engine from a vendored amalgamation that carries the Haybarn extension trust root (see Extension trust):

cargo new my-app && cd my-app
cargo add haybarn -F bundled

use haybarn::{params, Connection, Result};

struct Bale {
    id: i32,
    label: String,
}

fn main() -> Result<()> {
    let conn = Connection::open_in_memory()?;
    conn.execute_batch(
        "CREATE TABLE bales (id INTEGER PRIMARY KEY, label TEXT);
         INSERT INTO bales VALUES (1, 'north field'), (2, 'south field');",
    )?;

    let bales = conn
        .prepare("FROM bales ORDER BY id")?
        .query_map([], |row| {
            Ok(Bale { id: row.get(0)?, label: row.get(1)? })
        })?
        .collect::<Result<Vec<_>>>()?;

    for b in bales {
        println!("{}: {}", b.id, b.label);
    }
    Ok(())
}

Migrating from duckdb-rs

Because haybarn is ABI-compatible, existing duckdb-rs code can switch with a single Cargo.toml line and no source changes — Cargo's package-rename keeps the import name as duckdb:

[dependencies]
duckdb = { package = "haybarn", version = "1.10503", features = ["bundled"] }

Every use duckdb::... keeps working. Fresh projects can instead depend on haybarn directly and write use haybarn::....

Loadable-extension authors (the experimental loadable-extension feature) must import the crate as haybarn, because haybarn-loadable-macros emits ::haybarn::ffi paths. The package = "haybarn" rename trick does not cover that case.

Extension trust

The bundled build compiles an amalgamation regenerated from the Haybarn engine. It embeds the single Haybarn RSA trust root for both core and community extensions and the haybarn-extensions.query.farm repositories. DuckDB-signed extensions will not load, by design.

Non-bundled paths are not yet wired for Haybarn. The system-library discovery (pkg-config / vcpkg) and DUCKDB_DOWNLOAD_LIB paths inherited from upstream still reference DuckDB. Use bundled until those are rebranded.

License & trademark

Licensed under MIT, preserved verbatim from upstream duckdb-rs. See NOTICE for the list of modifications.

Haybarn is independent of and not endorsed by the DuckDB Foundation. DuckDB is a trademark of the DuckDB Foundation (https://duckdb.org/trademark_guidelines). "Haybarn, powered by DuckDB."

The original duckdb-rs project lives at https://github.com/duckdb/duckdb-rs.