DuckDB Server

A Rust-based server that runs a local DuckDB instance and support queries over Web Sockets or HTTP/HTTPS, returning data in either Apache Arrow or JSON format.

Note: This package provides a local DuckDB server. To instead use DuckDB-WASM in the browser, use the wasmConnector in the mosaic-core package.

Usage

Install and run the server with

cargo install duckdb-server
duckdb-server

You can disable or customize logging with the RUST_LOG environment variable.

env RUST_LOG="" duckdb-server

The server can reuse existing sockets with listenfd.

systemfd --no-pid -s http::3000 -- duckdb-server

To use HTTPS and HTTP/2, you need localhost.pem and localhost-key.pem in the current directory or at the env variable CARGO_MANIFEST_DIR.

Create certificates for localhost with mkcert

mkcert localhost

API

The server supports queries via HTTP GET, POST, and Arrow Flight. The GET endpoint is useful for debugging. For example, you can query it with this url.

Each endpoint takes a JSON object with a command in the type. The server supports the following commands.

exec

Executes the SQL query in the sql field.

arrow

Executes the SQL query in the sql field and returns the result in Apache Arrow format.

json

Executes the SQL query in the sql field and returns the result in JSON format.

Developers

Build

Build the release binary with

cargo build --release

Develop

To run the server and restart it when the code changes, install cargo-watch and systemfd with

cargo install cargo-watch systemfd

Then run the server with

systemfd --no-pid -s https::3000 -- cargo watch -x run

Or just use (but this won't restart when the code changes)

cargo run

Before sending a pull request, run the tests with

cargo test
cargo clippy
cargo fmt

Run the benchmarks with

cargo bench

Update Dependencies

Update the lockfile with cargo update and look for outdated dependencies with cargo-outdated cargo outdated -d 1.

Publishing

Bump the version in Cargo.toml and then run cargo publish.