FoundationDB Rust Client API

This is a wrapper library around the FoundationDB (Fdb) C API. It implements futures based interfaces over the Fdb future C implementations.

Prerequisites

• Rust 1.70.0 or more,
• FoundationDB's client installed.

Platform Support

Support for different platforms ("targets") are organized into three tiers, each with a different set of guarantees. For more information on the policies for targets at each tier, see the Target Tier Policy.

For more information on the policies for targets at each tier, see the

Target Tier Policy

Tier 1

Tier 1 targets can be thought of as "guaranteed to work". This means that:

• we are actively checking correctness with the BindingTester,
• we are running classic Rust tests on each pull requests,
• you can use the crate on the platform.

Tier 2

Tier 2 targets can be thought of as "guaranteed to build". This means that:

• we are running classic Rust tests on each pull requests,
• you can use the crate on the platform.

But we are not checking correctness.

Tier 3

Tier 3 targets are platforms we would like to have as Tier 2. You might be able to compile, but no CI has been set up.

Getting Started

Install FoundationDB

You first need to install FoundationDB. You can follow the official documentation:

• Getting Started on Linux
• Getting started on macOS

Add dependencies on foundationdb-rs

cargo add foundationdb -F embedded-fdb-include
cargo add futures

This Rust crate is not tied to any Async Runtime.

Exposed features

Hello, World using the crate

We are going to use the Tokio runtime for this example:

use futures::prelude::*;

#[tokio::main]
async fn main() {
    // Safe because drop is called before the program exits
    let network = unsafe { foundationdb::boot() };

    // Have fun with the FDB API
    hello_world().await.expect("could not run the hello world");

    // shutdown the client
    drop(network);
}

async fn hello_world() -> foundationdb::FdbResult<()> {
    let db = foundationdb::Database::default()?;

    // write a value in a retryable closure
    match db
        .run(|trx, _maybe_committed| async move {
            trx.set(b"hello", b"world");
            Ok(())
        })
        .await
    {
        Ok(_) => println!("transaction committed"),
        Err(_) => eprintln!("cannot commit transaction"),
    };

    // read a value
    match db
        .run(|trx, _maybe_committed| async move { Ok(trx.get(b"hello", false).await.unwrap()) })
        .await
    {
        Ok(slice) => assert_eq!(b"world", slice.unwrap().as_ref()),
        Err(_) => eprintln!("cannot commit transaction"),
    }

    Ok(())
}

Additional notes

The class-scheduling tutorial

The official FoundationDB's tutorial is called the Class Scheduling. You can find the Rust version in the examples.

The blob tutorial

The official FoundationDB documentation provides also another topic which is further discussed inside a design recipe. A Rust implementation can be found here.

Another example, explores how to use subspaces to attach metadata to our blob.

Must-read documentations

• Developer Guide
• Data Modeling Guide

Initialization

Due to limitations in the C API, the Client and it's associated Network can only be initialized and run once per the life of a process. Generally the foundationdb::boot function will be enough to initialize the Client. See foundationdb::api for more configuration options of the Fdb Client.

Migration from 0.4 to 0.5

The initialization of foundationdb API has changed due to undefined behavior being possible with only safe code (issues #170, #181, pulls #179, #182).

Previously you had to wrote foundationdb::boot().expect("failed to initialize Fdb");, now this can be converted to:

// Safe because drop is called before the program exits
let network = unsafe { foundationdb::boot() };

// do stuff

// cleanly shutdown the client
drop(network);

API stability

WARNING Until the 1.0 release of this library, the API may be in constant flux.