dustmaps-api

https://dustmaps.snad.space

A small, fast HTTP service that answers dust-extinction queries: given a sky position (and, for Bayestar19, a distance), it returns E(B−V), matching the reference Python dustmaps package.

Layout

• app/: the Rust/axum server. Mmaps the prebuilt .npy maps and serves the
• ve endpoints.
• data-prep/: a uv-run Python package that downloads the raw CSFD and Bayestar19 releases and converts them to the flat .npy layout the server reads. Not a runtime dependency of the server.
• integration-tests/: golden tests that compare the running server's answers against the reference Python dustmaps package.

Running

$ docker compose up --build

Builds the maps, compiles the server, and serves on port 80 (see docker-compose.yml / Dockerfile). There is no configuration beyond RUST_LOG; data path and listen address are fixed for this single deployment.

For local dev, docker compose -f docker-compose-dev.yml up --build serves on localhost:8080.

Testing

$ cargo test --manifest-path app/Cargo.toml          # unit + HTTP tests, no map data needed
$ uv run --project data-prep --group test pytest -q data-prep/tests
$ docker build --target golden-tests -t dustmaps-api:golden-tests . \
    && docker run --rm dustmaps-api:golden-tests      # full pipeline vs. Python dustmaps

Attribution

• CSFD: Chiang (2023).
• Bayestar19: Green et al. (2019).
• Both accessed during data prep via the dustmaps package (Green 2018).

License

MIT.