build-a-rust-app-with-cockroachdb.md

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Build a Rust App with CockroachDB and the Rust Postgres Driver	Learn how to use CockroachDB from a simple Rust application with a low-level client driver.	true	false

This tutorial shows you how build a simple Rust application with CockroachDB and the Rust Postgres driver.

We have tested the Rust Postgres driver enough to claim beta-level support. If you encounter problems, please open an issue with details to help us make progress toward full support.

Before you begin

{% include {{page.version.version}}/app/before-you-begin.md %}

Step 1. Specify the Rust Postgres driver as a dependency

Update your Cargo.toml file to specify a dependency on the Rust Postgres driver, as described in the official documentation.

Additionally, include the OpenSSL bindings and Rust Postgres OpenSSL crates as dependencies.

Step 2. Create the maxroach users 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 %}

$ cockroach cert create-client maxroach --certs-dir=certs --ca-key=my-safe-directory/ca.key

Step 4. Run the Rust 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.

Basic statements

First, use the following code to connect as the maxroach user and execute some basic SQL statements, inserting rows and reading and printing the rows.

Download the basic-sample.rs file, or create the file yourself and copy the code into it.

{% include copy-clipboard.html %}

{% include {{ page.version.version }}/app/basic-sample.rs %}

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.rs file, or create the file yourself and copy the code into it.

{{site.data.alerts.callout_info}} CockroachDB may require the client to retry a transaction in case of read/write contention. CockroachDB provides a generic retry function that runs inside a transaction and retries it as needed. You can copy and paste the retry function from here into your code. {{site.data.alerts.end}}

{% include copy-clipboard.html %}

{% include {{ page.version.version }}/app/txn-sample.rs %}

After running the code, use the built-in SQL client to verify that funds were transferred from one account to another:

{% include copy-clipboard.html %}

$ cockroach sql --certs-dir=certs -e 'SELECT id, balance FROM accounts' --database=bank

+----+---------+
| id | balance |
+----+---------+
|  1 |     900 |
|  2 |     350 |
+----+---------+
(2 rows)

Step 1. Specify the Rust Postgres driver as a dependency

Update your Cargo.toml file to specify a dependency on the Rust Postgres driver, as described in the official documentation.

Step 2. Create the maxroach users and bank database

{% include {{page.version.version}}/app/insecure/create-maxroach-user-and-bank-database.md %}

Step 3. Create a table in the new database

As the maxroach user, use the built-in SQL client to create an accounts table in the new database.

{% include copy-clipboard.html %}

$ cockroach sql --insecure \
--database=bank \
--user=maxroach \
-e 'CREATE TABLE accounts (id INT PRIMARY KEY, balance INT)'

Step 4. Run the Rust 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.

Basic statements

First, use the following code to connect as the maxroach user and execute some basic SQL statements, inserting rows and reading and printing the rows.

Download the basic-sample.rs file, or create the file yourself and copy the code into it.

{% include copy-clipboard.html %}

{% include {{ page.version.version }}/app/insecure/basic-sample.rs %}

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.rs file, or create the file yourself and copy the code into it.

{{site.data.alerts.callout_info}} CockroachDB may require the client to retry a transaction in case of read/write contention. CockroachDB provides a generic retry function that runs inside a transaction and retries it as needed. You can copy and paste the retry function from here into your code. {{site.data.alerts.end}}

{% include copy-clipboard.html %}

{% include {{ page.version.version }}/app/insecure/txn-sample.rs %}

After running the code, use the built-in SQL client to verify that funds were transferred from one account to another:

{% include copy-clipboard.html %}

$ cockroach sql --insecure -e 'SELECT id, balance FROM accounts' --database=bank

+----+---------+
| id | balance |
+----+---------+
|  1 |     900 |
|  2 |     350 |
+----+---------+
(2 rows)

What's next?

Read more about using the Rust Postgres driver.

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