ClickHouse: Rust (`clickhouse` crate)

Typed rows over the ClickHouse HTTP interface (RowBinary format).

The only change

# CLICKHOUSE_URL
 https://clickhouse.internal:8443
 https://warehouse.internal:8443
# CLICKHOUSE_USER / CLICKHOUSE_PASSWORD
 ClickHouse user
 MachWarehouse user

For https URLs enable one of the crate’s TLS features (for example rustls-tls) in Cargo.toml.

Run

cargo run

Libraries: clickhouse 0.15.3, tokio 1.54.1, serde 1.0.229.

Source

The program as it is kept and tested in the Mach Database Warehouse repository; highlighted lines read the connection setting.

src/main.rs

//! Prints revenue per country with the `clickhouse` crate over the ClickHouse
//! HTTP interface. Plain ClickHouse client code: nothing here knows about
//! MachWarehouse. Load the table first with any other example.

use clickhouse::{Client, Row};
use serde::Deserialize;

#[derive(Debug, Row, Deserialize)]
struct CountryRevenue {
    country: String,
    events: u64,
    revenue: f64,
}

#[tokio::main]
async fn main() -> Result<(), clickhouse::error::Error> {
    let env = |k: &str, d: &str| std::env::var(k).unwrap_or_else(|_| d.to_owned());
    let client = Client::default()
        .with_url(env("CLICKHOUSE_URL", "http://localhost:8123"))
        .with_user(env("CLICKHOUSE_USER", "default"))
        .with_password(env("CLICKHOUSE_PASSWORD", ""))
        .with_database(env("CLICKHOUSE_DATABASE", "default"));

    let rows = client
        .query(
            "SELECT country, count() AS events, toFloat64(sum(revenue)) AS revenue \
             FROM events GROUP BY country ORDER BY revenue DESC",
        )
        .fetch_all::<CountryRevenue>()
        .await?;
    for r in rows {
        println!("{}\t{}\t{:.2}", r.country, r.events, r.revenue);
    }
    Ok(())
}

Cargo.toml

[package]
name = "clickhouse-rust-example"
version = "0.1.0"
edition = "2024"
publish = false

# Standalone: not a member of the MachWarehouse workspace.
[workspace]

[dependencies]
clickhouse = "0.15.3"
serde = { version = "1.0.229", features = ["derive"] }
tokio = { version = "1.54.1", features = ["macros", "rt-multi-thread"] }