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Build a Ruby application

The following tutorial shows a small Ruby application that connects to a YugabyteDB cluster using the Ruby Pg driver and performs basic SQL operations. Use the application as a template to get started with Yugabyte Cloud in Ruby.

Prerequisites

Ruby 3.1 or later.
OpenSSL 1.1.1 or later (used by libpq and pg to establish secure SSL connections).
libpq. Homebrew users on macOS can install using brew install libpq. You can download the PostgreSQL binaries and source from PostgreSQL Downloads.
Ruby pg. To install Ruby pg, run the following command:
```
gem install pg -- --with-pg-include=<path-to-libpq>/libpq/include --with-pg-lib=<path-to-libpq>/libpq/lib
```
Replace <path-to-libpq> with the path to the libpq installation; for example, /usr/local/opt.

Yugabyte Cloud

You have a cluster deployed in Yugabyte Cloud. To get started, use the Quick start.
You downloaded the cluster CA certificate. Refer to Download your cluster certificate.
You have added your computer to the cluster IP allow list. Refer to Assign IP Allow Lists.

Clone the application from GitHub

Clone the sample application to your computer:

git clone https://github.com/yugabyte/yugabyte-simple-ruby-app && cd yugabyte-simple-ruby-app

Provide connection parameters

The application needs to establish a connection to the YugabyteDB cluster. To do this:

Open the sample-app.rb file.
Set the following configuration-related parameters:
- host - the host name of your YugabyteDB cluster. To obtain a Yugabyte Cloud cluster host name, sign in to Yugabyte Cloud, select your cluster on the Clusters page, and click Settings. The host is displayed under Network Access.
- port - the port number that will be used by the driver (the default YugabyteDB YSQL port is 5433).
- dbname - the name of the database you are connecting to (the default database is named yugabyte).
- user and password - the username and password for the YugabyteDB database. If you are using the credentials you created when deploying a cluster in Yugabyte Cloud, these can be found in the credentials file you downloaded.
- sslmode - the SSL mode to use. Yugabyte Cloud requires SSL connections; use verify-full.
- sslrootcert - the full path to the Yugabyte Cloud cluster CA certificate.
Save the file.

Build and run the application

Make the application file executable.

chmod +x sample-app.rb

Run the application.

$ ./sample-app.rb

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 Ruby application that works with Yugabyte Cloud.

Explore the application logic

Open the sample-app.rb file in the yugabyte-simple-ruby-app folder to review the methods.

connect

The connect method establishes a connection with your cluster via the libpqxx driver.

conn = PG.connect(
    host: '',
    port: '5433',
    dbname: 'yugabyte',
    user: '',
    password: '',
    sslmode: 'verify-full',
    sslrootcert: ''
    );

create_database

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

conn.exec("DROP TABLE IF EXISTS DemoAccount");

conn.exec("CREATE TABLE DemoAccount ( \
            id int PRIMARY KEY, \
            name varchar, \
            age int, \
            country varchar, \
            balance int)");

conn.exec("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.

begin
    puts ">>>> Selecting accounts:\n";

    rs = conn.exec("SELECT name, age, country, balance FROM DemoAccount");

    rs.each do |row|
        puts "name=%s, age=%s, country=%s, balance=%s\n" % [row['name'], row['age'], row['country'], row['balance']];
    end

ensure
    rs.clear if rs
end

transfer_money_between_accounts

The transferMoneyBetweenAccounts method updates your data consistently with distributed transactions.

begin
    conn.transaction do |txn|
        txn.exec_params("UPDATE DemoAccount SET balance = balance - $1 WHERE name = \'Jessica\'", [amount]);
        txn.exec_params("UPDATE DemoAccount SET balance = balance + $1 WHERE name = \'John\'", [amount]);
    end

    puts ">>>> Transferred %s between accounts.\n" % [amount];

rescue PG::TRSerializationFailure => e
    puts "The operation is aborted due to a concurrent transaction that is modifying the same set of rows. \
            Consider adding retry logic for production-grade applications.";
    raise
end

Learn more

Ruby pg driver

libpq driver

Explore more applications

Deploy clusters in Yugabyte Cloud

Connect to applications in Yugabyte Cloud