Preparing benchmark datasets

The chutoro-bench-datasets crate provides a typed lifecycle for benchmark dataset preparation. It is intended for benchmark and evaluation tooling that needs to fetch source data, validate it, prepare benchmark-ready bytes, and publish a final artefact through explicit infrastructure ports.

Use this crate when writing benchmark dataset recipes or tests around dataset adapters. It is not required for normal clustering with chutoro-core.

Add chutoro-bench-datasets when the application owns dataset preparation. Enable the testing feature in tests to use in-memory and filesystem adapters.

[dependencies]
chutoro-bench-datasets = "0.1.0"

[dev-dependencies]
chutoro-bench-datasets = { version = "0.1.0", features = ["testing"] }

Implement DatasetRecipe for each dataset. Its associated types model the four ordered phases: Fetched, Validated, Prepared, and Published. Each phase consumes the previous phase output, so callers cannot skip validation before preparation at compile time.

Recipes access I/O through RecipeContext instead of storing infrastructure state directly:

• Fetcher reads declared source bytes.
• Storage caches mutable intermediate artefacts.
• Publisher writes the final prepared artefact.

The testing feature exposes InMemoryFetcher, InMemoryStorage, InMemoryPublisher, FilesystemFetcher, and StubRecipe for adapter contract tests and lifecycle tests.

use bytes::Bytes;
use chutoro_bench_datasets::{
    PublishedArtefact, RecipeContext, SourceUrl, run_recipe,
    testing::{InMemoryFetcher, InMemoryPublisher, InMemoryStorage, StubRecipe},
};

let source = SourceUrl::parse("https://example.test/dataset.bin")?;
let fetcher = InMemoryFetcher::new([(source.clone(), Bytes::from_static(b"abc"))]);
let storage = InMemoryStorage::default();
let publisher = InMemoryPublisher::default();
let ctx = RecipeContext::new(&fetcher, &storage, &publisher);
let recipe = StubRecipe::new("example", vec![source]);

let published = run_recipe(&recipe, &ctx)?;
assert_eq!(published.manifest_uri().as_str(), "manifests/example.json");
# Ok::<(), chutoro_bench_datasets::RecipeError>(())

For the design rationale behind the four-phase trait and port split, see ADR-004: Benchmark dataset recipe trait.