Build a Ruby App with CockroachDB

2020-02-16

This tutorial shows you how build a simple Ruby application with CockroachDB using a PostgreSQL-compatible driver or ORM.

We have tested the Ruby pg driver and the ActiveRecord ORM enough to claim beta-level support, so those are featured here. If you encounter problems, please open an issue with details to help us make progress toward full support.

Before you begin

  1. Install CockroachDB.
  2. Start up a secure or insecure local cluster.
  3. Choose the instructions that correspond to whether your cluster is secure or insecure:

Step 1. Install the Ruby pg driver

To install the Ruby pg driver, run the following command:

$ gem install pg
## Step 2. Create the `maxroach` user and `bank` database {% include {{page.version.version}}/app/create-maxroach-user-and-bank-database.md %} ## Step 3. Generate a certificate for the `maxroach` user Create a certificate and key for the `maxroach` user by running the following command. The code samples will run as this user. {% include copy-clipboard.html %} ~~~ shell $ cockroach cert create-client maxroach --certs-dir=certs --ca-key=my-safe-directory/ca.key ~~~ ## Step 4. Run the Ruby code Now that you have a database and a user, you'll run code to create a table and insert some rows, and then you'll run code to read and update values as an atomic [transaction](transactions.html). ### Basic statements The following code connects as the `maxroach` user and executes some basic SQL statements: creating a table, inserting rows, and reading and printing the rows. Download the basic-sample.rb file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ ruby {% include {{page.version.version}}/app/basic-sample.rb %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ ruby basic-sample.rb ~~~ The output should be: ~~~ Initial balances: {"id"=>"1", "balance"=>"1000"} {"id"=>"2", "balance"=>"250"} ~~~ ### Transaction (with retry logic) Next, use the following code to again connect as the `maxroach` user but this time execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted. Download the txn-sample.rb file, or create the file yourself and copy the code into it. {% include v2.1/client-transaction-retry.md %} {% include copy-clipboard.html %} ~~~ ruby {% include {{page.version.version}}/app/txn-sample.rb %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ ruby txn-sample.rb ~~~ To verify that funds were transferred from one account to another, start the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ cockroach sql --certs-dir=certs --database=bank ~~~ To check the account balances, issue the following statement: {% include copy-clipboard.html %} ~~~ sql > SELECT id, balance FROM accounts; ~~~ ~~~ +----+---------+ | id | balance | +----+---------+ | 1 | 900 | | 2 | 350 | +----+---------+ (2 rows) ~~~
## Step 2. Create the `maxroach` user and `bank` database {% include {{page.version.version}}/app/insecure/create-maxroach-user-and-bank-database.md %} ## Step 3. Run the Ruby code Now that you have a database and a user, you'll run code to create a table and insert some rows, and then you'll run code to read and update values as an atomic [transaction](transactions.html). ### Basic statements The following code connects as the `maxroach` user and executes some basic SQL statements: creating a table, inserting rows, and reading and printing the rows. Download the basic-sample.rb file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ ruby {% include {{page.version.version}}/app/insecure/basic-sample.rb %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ ruby basic-sample.rb ~~~ The output should be: ~~~ Initial balances: {"id"=>"1", "balance"=>"1000"} {"id"=>"2", "balance"=>"250"} ~~~ ### Transaction (with retry logic) Next, use the following code to again connect as the `maxroach` user but this time execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted. Download the txn-sample.rb file, or create the file yourself and copy the code into it. {% include v2.1/client-transaction-retry.md %} {% include copy-clipboard.html %} ~~~ ruby {% include {{page.version.version}}/app/insecure/txn-sample.rb %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ ruby txn-sample.rb ~~~ To verify that funds were transferred from one account to another, start the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ cockroach sql --insecure --database=bank ~~~ To check the account balances, issue the following statement: {% include copy-clipboard.html %} ~~~ sql > SELECT id, balance FROM accounts; ~~~ ~~~ +----+---------+ | id | balance | +----+---------+ | 1 | 900 | | 2 | 350 | +----+---------+ (2 rows) ~~~

What's next?

Read more about using the Ruby pg driver.

You might also be interested in using a local cluster to explore the following CockroachDB benefits: