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use clickhouse::Client;
use clickhouse::Row;
use clickhouse::sql::Identifier;
use serde::{Deserialize, Serialize};
use std::env;
// This example requires three environment variables with your instance credentials to be set
//
// - CLICKHOUSE_URL (e.g., https://myservice.clickhouse.cloud:8443)
// - CLICKHOUSE_USER
// - CLICKHOUSE_PASSWORD
//
// Works with either `rustls-tls` or `native-tls` cargo features.
#[tokio::main]
async fn main() -> clickhouse::error::Result<()> {
let table_name = "chrs_cloud";
let client = Client::default()
.with_url(read_env_var("CLICKHOUSE_URL"))
.with_user(read_env_var("CLICKHOUSE_USER"))
.with_password(read_env_var("CLICKHOUSE_PASSWORD"));
// `wait_end_of_query` is required in this case, as we want these DDLs to be executed
// on the entire Cloud cluster before we receive the response.
// See https://clickhouse.com/docs/en/interfaces/http/#response-buffering
client
.query("DROP TABLE IF EXISTS ?")
.bind(Identifier(table_name))
.with_setting("wait_end_of_query", "1")
.execute()
.await?;
// Note that you could just use MergeTree with CH Cloud, and omit the `ON CLUSTER` clause.
// The same applies to other engines as well;
// e.g., ReplacingMergeTree will become SharedReplacingMergeTree and so on.
// See https://clickhouse.com/docs/en/cloud/reference/shared-merge-tree#enabling-sharedmergetree
client
.query("CREATE TABLE ? (id Int32, name String) ENGINE MergeTree ORDER BY id")
.bind(Identifier(table_name))
.with_setting("wait_end_of_query", "1")
.execute()
.await?;
let mut insert = client.insert::<MyRow>(table_name).await?;
insert
.write(&MyRow {
id: 42,
name: "foo".into(),
})
.await?;
insert.end().await?;
let data = client
.query("SELECT ?fields FROM ?")
.bind(Identifier(table_name))
// This setting is optional; use it when you need strong consistency guarantees on the reads
// See https://clickhouse.com/docs/en/cloud/reference/shared-merge-tree#consistency
.with_setting("select_sequential_consistency", "1")
.fetch_all::<MyRow>()
.await?;
println!("Stored data: {data:?}");
Ok(())
}
#[derive(Debug, Serialize, Deserialize, Row)]
struct MyRow {
id: i32,
name: String,
}
fn read_env_var(key: &str) -> String {
env::var(key).unwrap_or_else(|_| panic!("{key} env variable should be set"))
}