api-server/src/main.rs

mod dem;

use axum::{
    extract::{Path, State},
    routing::get,
    Router,
};
use axum_macros::debug_handler;
use std::env;

use tower_http::services::ServeDir;

use dem::DatasetRepository;

use tracing::info;


const DEFAULT_DATA_DIR: &str = "/data";
const DEFAULT_PORT: &str = "3000";

//#[tokio::main(flavor = "current_thread")]
#[tokio::main]
async fn main() {
    // initialize tracing
    tracing_subscriber::fmt::init();


    let config = load_config().unwrap();
    let cache = DatasetRepository::new(config.basedir);

    let serve_dir = ServeDir::new("assets");

    // build our application with a route
    let app = Router::new()
        .route("/elevation/:lat/:lon", get(get_elevation))
        .nest_service("/", serve_dir)
        .with_state(cache);

    let host = format!("[::]:{}", config.port);
    info!("Will start server on {host}");

    let listener = tokio::net::TcpListener::bind(host).await.unwrap();
    axum::serve(listener, app).await.unwrap();
}

#[debug_handler]
async fn get_elevation(State(dsr): State<DatasetRepository>, Path((lat, lon)): Path<(f64, f64)>) -> String {
    let ele = dem::elevation_from_coordinates(dsr, lat, lon);
    let myele = ele.await;
    format!("{myele}")
}


fn load_config() -> Result<Config, env::VarError> {
    Ok(Config {
        basedir: env::var("DEM_LOCATION").unwrap_or_else(|_| DEFAULT_DATA_DIR.to_string()),
        port: env::var("HTTP_PORT").unwrap_or_else(|_| DEFAULT_PORT.to_string()),
    })
}

struct Config {
    basedir: String,
    port: String,
}