Drasi 0.1.0

drasi-dotnet

Embed the Drasi continuous-query engine in .NET.

A Rust cdylib hosts drasi-lib behind a small C ABI. C# binds it with [LibraryImport] and wraps it in an idiomatic façade (IAsyncDisposable, IAsyncEnumerable, typed errors). See docs/api-reference.md for the public API.

Requirements

• Rust stable (see rust-toolchain.toml) to build the native library
• .NET 8+ to consume it (net8.0 LTS is the API floor)

Consumers of the NuGet package do not need a Rust toolchain. Prebuilt binaries ship for win-x64, linux-x64, linux-arm64, osx-x64, and osx-arm64.

Build native + run the sample

From the repo root:

cargo build --release --manifest-path native/Cargo.toml
dotnet run --project examples/Quickstart

Or:

./scripts/run-quickstart.sh

Download plugins from ghcr.io and use them as a source and a reaction (needs network):

dotnet run --project examples/Plugins

Generic host + DI — configure Drasi at startup; the host starts it, applies the topology, and stops it:

dotnet run --project examples/Hosted

The sample copies libdrasi_ffi.dylib / .so / drasi_ffi.dll next to the app. The C# library also resolves the dylib from native/target/{release,debug} so a plain dotnet run works after a cargo build.

Expected output looks like:

  Add {"id":"o1","total":42}
open orders: [{"id":"o1","total":42}]

Both samples pass an ILoggerFactory (console). Quickstart logs at Warning; the plugins sample uses Information so reaction/log output shows up. Native logs no longer need RUST_LOG when a factory is set.

Quickstart shape

using var logs = LoggerFactory.Create(builder => builder.AddSimpleConsole());
await using var drasi = await Engine.CreateAsync("dotnet-demo", new EngineOptions
{
    LoggerFactory = logs,
});
await drasi.StartAsync();
await drasi.AddSourceAsync("orders");
await drasi.AddQueryAsync(
    "open",
    "MATCH (o:Order) WHERE o.status = 'open' RETURN o.id AS id, o.total AS total",
    ["orders"]);
await drasi.WaitForQueryAsync("open");
await foreach (var evt in drasi.QueryResultsAsync("open"))
{
    foreach (var diff in evt.Results)
        Console.WriteLine($"{diff.Type} {diff.Data}");
}

await drasi.PushChangeAsync("orders", new SourceChange
{
    Op = ChangeOp.Insert,
    Id = "o1",
    Labels = ["Order"],
    Properties = new JsonObject { ["id"] = "o1", ["status"] = "open", ["total"] = 42 },
});

DrasiVersion exposes Core / Lib / Sdk / Package. ShutdownAsync releases native stores (including the RocksDB lock) before dispose.

Hosted apps declare the topology in AddDrasi; no extra IHostedService is required:

builder.Services.AddDrasi("orders-app", drasi =>
{
    drasi.AddSource("orders");
    drasi.AddQuery("open",
        "MATCH (o:Order) WHERE o.status = 'open' RETURN o.id AS id, o.total AS total",
        ["orders"]);
    drasi.AddReaction("watch", ["open"], evt =>
    {
        foreach (var diff in evt.Results)
            Console.WriteLine($"{diff.Type} {diff.Data}");
    });
});
await builder.Build().RunAsync();

Push into Engine from the rest of the app (GetRequiredService<Engine>()), or Seed changes that should fire at startup.

Errors expose a stable Code (DrasiErrorCodes). Catch DrasiException or a more specific type (UnknownKindException, SourceException, …).

Pack (local RID)

./scripts/pack.sh osx-arm64   # or win-x64, linux-x64, linux-arm64, osx-x64

CI builds every declared RID and verifies the nupkg loads without Rust. Tagged releases (vMAJOR.MINOR.PATCH) publish to nuget.org. See docs/releasing.md.

Layout

native/                 Rust cdylib (C ABI)
src/Drasi/              C# library
examples/Quickstart/    Console sample
examples/Plugins/       Install source/mock + reaction/log from ghcr.io
examples/Hosted/        Generic host; configure topology in AddDrasi
tests/Drasi.Tests/      Public API tests
docs/api-reference.md   API surface + gap audit

License

Apache-2.0. See LICENSE.