Build a Go App with CockroachDB

2020-02-16

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

We have tested the Go pq driver and the GORM 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 Go pq driver

To install the Go pq driver, run the following command:

$ go get -u github.com/lib/pq
## 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 Go 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 First, use the following code to connect as the `maxroach` user and execute some basic SQL statements, creating a table, inserting rows, and reading and printing the rows. Download the basic-sample.go file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ go {% include {{ page.version.version }}/app/basic-sample.go %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ go run basic-sample.go ~~~ The output should be: ~~~ Initial balances: 1 1000 2 250 ~~~ ### Transaction (with retry logic) Next, use the following code to again connect as the `maxroach` user but this time will 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.go file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ go {% include {{ page.version.version }}/app/txn-sample.go %} ~~~ CockroachDB may require the [client to retry a transaction](transactions.html#transaction-retries) in case of read/write contention. CockroachDB provides a generic **retry function** that runs inside a transaction and retries it as needed. For Go, the CockroachDB retry function is in the `crdb` package of the CockroachDB Go client. To install Clone the library into your `$GOPATH` as follows: {% include copy-clipboard.html %} ~~~ shell $ mkdir -p $GOPATH/src/github.com/cockroachdb ~~~ {% include copy-clipboard.html %} ~~~ shell $ cd $GOPATH/src/github.com/cockroachdb ~~~ {% include copy-clipboard.html %} ~~~ shell $ git clone git@github.com:cockroachdb/cockroach-go.git ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ go run txn-sample.go ~~~ The output should be: ~~~ shell Success ~~~ To verify that funds were transferred from one account to another, use the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ cockroach sql --certs-dir=certs -e 'SELECT id, balance FROM accounts' --database=bank ~~~ ~~~ +----+---------+ | 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 Go 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 First, use the following code to connect as the `maxroach` user and execute some basic SQL statements, creating a table, inserting rows, and reading and printing the rows. Download the basic-sample.go file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ go {% include {{ page.version.version }}/app/insecure/basic-sample.go %} ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ go run basic-sample.go ~~~ The output should be: ~~~ Initial balances: 1 1000 2 250 ~~~ ### Transaction (with retry logic) Next, use the following code to again connect as the `maxroach` user but this time will 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.go file, or create the file yourself and copy the code into it. {% include copy-clipboard.html %} ~~~ go {% include {{ page.version.version }}/app/insecure/txn-sample.go %} ~~~ CockroachDB may require the [client to retry a transaction](transactions.html#transaction-retries) in case of read/write contention. CockroachDB provides a generic **retry function** that runs inside a transaction and retries it as needed. For Go, the CockroachDB retry function is in the `crdb` package of the CockroachDB Go client. To install the [CockroachDB Go client](https://github.com/cockroachdb/cockroach-go), run the following command: {% include copy-clipboard.html %} ~~~ shell $ go get -d github.com/cockroachdb/cockroach-go ~~~ Then run the code: {% include copy-clipboard.html %} ~~~ shell $ go run txn-sample.go ~~~ The output should be: ~~~ shell Success ~~~ To verify that funds were transferred from one account to another, use the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ 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 Go pq driver.

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