ecmwf-opendata (Rust)

Rust client for ECMWF Open Data.

API documentation (docs.rs): https://docs.rs/ecmwf-opendata

This crate is a Rust re-implementation of the core functionality of the upstream Python project ecmwf-opendata:

Build MARS-like requests (keyword/value pairs)
Resolve request → data URLs
Download whole files, or download selected fields via the .index sidecar using HTTP Range requests

Chinese documentation: see README.zh-CN.md.

Install

cargo add ecmwf-opendata

Library usage

1) Python-like `Client(...)` options

Python:

client = Client(
    source="ecmwf",
    model="ifs",
    resol="0p25",
    preserve_request_order=False,
    infer_stream_keyword=True,
)

Rust:

use ecmwf_opendata::{Client, ClientOptions};

let opts = ClientOptions {
    source: "ecmwf".to_string(),
    model: "ifs".to_string(),
    resol: "0p25".to_string(),
    preserve_request_order: false,
    infer_stream_keyword: true,
    ..ClientOptions::default()
};

let client = Client::new(opts)?;
# Ok::<(), ecmwf_opendata::Error>(())

source can be a known mirror ("ecmwf", "aws", "azure", "google") or a custom base URL ("https://...").

2) Request builder (kwargs-ish)

use ecmwf_opendata::{Client, ClientOptions, Request};

let client = Client::new(ClientOptions::default())?;

let req = Request::new()
    .r#type("fc")
    .param("msl")
    .step(240)
    .target("data.grib2");

let result = client.retrieve_request(req)?;
println!("Downloaded {} bytes", result.size_bytes);
# Ok::<(), ecmwf_opendata::Error>(())

3) `retrieve_pairs`: strongest “kwargs/dict” feel

use ecmwf_opendata::{Client, ClientOptions};

let client = Client::new(ClientOptions::default())?;

let result = client.retrieve_pairs([
    ("type", "fc".into()),
    ("param", "msl".into()),
    ("step", 240.into()),
    ("target", "data.grib2".into()),
])?;

println!("{}", result.datetime);
# Ok::<(), ecmwf_opendata::Error>(())

CLI

This repository also includes a small CLI example (as a Cargo example target).

cargo run --example cli -- retrieve data.grib2

cargo run --example cli -- download data.grib2

Notes / limitations

This is intentionally a “core features” port; it does not aim to fully replicate every upstream Python feature.
latest() probing depends on endpoint availability. If it fails, specify date/time explicitly.
Data usage is subject to ECMWF Open Data terms (including attribution requirements).

ecmwf-opendata 0.1.2