Build a Rust application that uses YSQL

The following tutorial shows a small Rust application that connects to a YugabyteDB cluster using the Rust-Postgres driver and performs basic SQL operations. Use the application as a template to get started with YugabyteDB Aeon in Rust.

Prerequisites

Rust development environment. The sample application was created for Rust 1.58 but should work for earlier and later versions.

Clone the application from GitHub

Clone the sample application to your computer:

git clone https://github.com/YugabyteDB-Samples/yugabyte-simple-rust-app.git && cd yugabyte-simple-rust-app

Provide connection parameters

If your cluster is running on YugabyteDB Aeon, you need to modify the connection parameters so that the application can establish a connection to the YugabyteDB cluster. (You can skip this step if your cluster is running locally and listening on 127.0.0.1:5433.)

To do this:

1. Open the sample-app.rs file in the src directory.

2. Set the following configuration-related constants:

   • HOST - the host name of your YugabyteDB cluster. For local clusters, use the default (127.0.0.1). For YugabyteDB Aeon, select your cluster on the Clusters page, and click Settings. The host is displayed under Connection Parameters.
   • PORT - the port number for the driver to use (the default YugabyteDB YSQL port is 5433).
   • DB_NAME - the name of the database you are connecting to (the default is yugabyte).
   • USER and PASSWORD - the username and password for the YugabyteDB database. For local clusters, use the defaults (yugabyte and yugabyte). For YugabyteDB Aeon, use the credentials in the credentials file you downloaded.
   • SSL_MODE - the SSL mode to use. YugabyteDB Aeon requires SSL connections; use SslMode::Require.
   • SSL_ROOT_CERT - the full path to the YugabyteDB Aeon cluster CA certificate.

3. Save the file.

Build and run the application

Build and run the application.

$ cargo run

The driver is included in the dependencies list of the Cargo.toml file and installed automatically the first time you run the application.

You should see output similar to the following:

>>>> Successfully connected to YugabyteDB!
>>>> Successfully created table DemoAccount.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 10000
name = John, age = 28, country = Canada, balance = 9000
>>>> Transferred 800 between accounts.
>>>> Selecting accounts:
name = Jessica, age = 28, country = USA, balance = 9200
name = John, age = 28, country = Canada, balance = 9800

You have successfully executed a basic Rust application that works with YugabyteDB Aeon.

Explore the application logic

Open the sample-app.rs file in the yugabyte-simple-rust-app/src folder to review the methods.

connect

The connect method establishes a connection with your cluster via the Rust-Postgres driver.

let mut cfg = Config::new();

cfg.host(HOST).port(PORT).dbname(DB_NAME).
    user(USER).password(PASSWORD).ssl_mode(SSL_MODE);

let mut builder = SslConnector::builder(SslMethod::tls())?;
builder.set_ca_file(SSL_ROOT_CERT)?;
let connector = MakeTlsConnector::new(builder.build());

let client = cfg.connect(connector)?;

create_database

The create_database method uses PostgreSQL-compliant DDL commands to create a sample database.

client.execute("DROP TABLE IF EXISTS DemoAccount", &[])?;

client.execute("CREATE TABLE DemoAccount (
                id int PRIMARY KEY,
                name varchar,
                age int,
                country varchar,
                balance int)", &[])?;

client.execute("INSERT INTO DemoAccount VALUES
                (1, 'Jessica', 28, 'USA', 10000),
                (2, 'John', 28, 'Canada', 9000)", &[])?;

select_accounts

The select_accounts method queries your distributed data using the SQL SELECT statement.

for row in client.query("SELECT name, age, country, balance FROM DemoAccount", &[])? {
    let name: &str = row.get("name");
    let age: i32 = row.get("age");
    let country: &str = row.get("country");
    let balance: i32 = row.get("balance");

    println!("name = {}, age = {}, country = {}, balance = {}",
        name, age, country, balance);
}

transfer_money_between_accounts

The transfer_money_between_accounts method updates your data consistently with distributed transactions.

let mut txn = client.transaction()?;

let exec_txn = || -> Result<(), DBError> {
    txn.execute("UPDATE DemoAccount SET balance = balance - $1 WHERE name = \'Jessica\'", &[&amount])?;
    txn.execute("UPDATE DemoAccount SET balance = balance + $1 WHERE name = \'John\'", &[&amount])?;
    txn.commit()?;

    Ok(())
};

Learn more

Rust-Postgres driver