Cassandra - Rust example (scylladb/scylla-rust-driver)

cassandra-rust-example.rs

use scylla::{SessionBuilder, IntoTypedRows};
use std::error::Error;
use std::env;
use std::time::Instant;
use dotenv::dotenv;

const QUERY_LIMIT: i32 = 5000;

#[tokio::main]
async fn main() -> Result<(), Box<dyn Error>> {
    // Load environment variables from .env file
    dotenv().ok();

    let nodes = env::var("DB_NODES")
        .expect("DB_NODES must be set")
        .split(',')
        .map(String::from)
        .collect::<Vec<String>>();
    let username = env::var("DB_USERNAME").expect("DB_USERNAME must be set");
    let password = env::var("DB_PASSWORD").expect("DB_PASSWORD must be set");

    let session = SessionBuilder::new()
        .known_nodes(&nodes)
        .user(&username, &password)
        .build()
        .await?;

    let start = Instant::now();
    let rows = session
        .query("SELECT id FROM gridia.event LIMIT ?", (QUERY_LIMIT,))
        .await?
        .rows
        .unwrap()
        .into_typed::<(i32,)>();
    let duration = start.elapsed();

    let count = rows.count();
    
    println!("Query executed in: {:?}", duration);
    println!("Number of rows returned: {}", count);

    Ok(())
}

cassandra.env

DB_NODES=db01.cloud.myserver.com:9042,db01.cloud.myserver.com:9043,db01.cloud.myserver.com:9044
DB_USERNAME=cassandra
DB_PASSWORD=cassandra