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

title	summary	toc	twitter
Build a Go App with CockroachDB	Learn how to use CockroachDB from a simple Go application with the Go pq driver.	false	true

Use pq Use GORM

This tutorial shows you how build a simple Go application with CockroachDB using a PostgreSQL-compatible driver or ORM. We've tested and can recommend the Go pq driver and the GORM ORM, so those are featured here.

Before You Begin

Make sure you have already installed CockroachDB.

Step 1. Install the Go pq driver

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

$ go get -u github.com/lib/pq

{% include app/common-steps.md %}

Step 5. 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.

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.

Copy the code or download it directly.

{% include app/basic-sample.go %}

Then run the code:

$ 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.

Copy the code or download it directly.

{% include app/txn-sample.go %}

With the default SERIALIZABLE isolation level, 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. For Go, the CockroachDB retry function is in the crdb package of the CockroachDB Go client. Clone the library into your $GOPATH as follows:

$ mkdir -p $GOPATH/github.com/cockroachdb
$ cd $GOPATH/github.com/cockroachdb
$ git clone [email protected]:cockroachdb/cockroach-go.git

Then run the code:

$ go run txn-sample.go

The output should just be:

Success

However, if you want to verify that funds were transferred from one account to another, use the built-in SQL client:

$ 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 core CockroachDB features:

• Data Replication
• Fault Tolerance & Recovery
• Automatic Rebalancing