Home > Quick start > 4. Build an application >

Build a Go application

The following tutorial creates a simple Go application that connects to a YugabyteDB cluster using the pq driver, performs a few basic database operations — creating a table, inserting data, and running a SQL query — and then prints the results to the screen.

Prerequisites

This tutorial assumes that:

YugabyteDB is up and running. If you are new to YugabyteDB, you can download, install, and have YugabyteDB up and running within minutes by following the steps in Quick start. Alternatively, you can use Yugabyte Cloud to get a fully managed database-as-a-service (DBaaS) for YugabyteDB.
Go version 1.8, or later, is installed.

SSL/TLS configuration

You can choose to enable or disable SSL for your local YugabyteDB cluster. Refer here to learn about configuring SSL/TLS for your YugabyteDB cluster. Yugabyte Cloud requires SSL connections, and SSL/TLS is enabled by default for client-side authentication.

CA certificate

Use the CA certficate generated above as part of the SSL/TLS configuration of your cluster.

In case of a Yugabyte Cloud cluster, to download the CA certificate for your cluster in Yugabyte Cloud, do the following:

On the Clusters tab, select a cluster.
Click Connect.
Click Connect to your application and download the CA cert.

OpenSSL

Install OpenSSL 1.1.1 or later only if you have a YugabyteDB setup with SSL/TLS enabled. Yugabyte Cloud clusters are always SSL/TLS enabled.

The following table summarizes the SSL modes and their support in the driver:

SSL Mode	Client driver behavior
disable	Supported
allow	Not supported
prefer	Not supported
require (default)	Supported
verify-ca	Supported
verify-full	Supported

Yugabyte Cloud requires SSL/TLS, and connections using SSL mode disable will fail.

Go PostgreSQL driver

The Go PostgreSQL driver package (pq) is a Go PostgreSQL driver for the database/sql package.

To install the package locally, run the following commands:

Note

Set the environment variable GO111MODULE before installing the lib/pq package if your Go version is 1.11 or higher.

$ export GO111MODULE=auto
$ go get github.com/lib/pq

Create the sample Go application

Create a file ybsql_hello_world.go and copy the contents below.

package main

import (
  "database/sql"
  "fmt"
  "log"

  _ "github.com/lib/pq"
)

const (
  host     = "127.0.0.1"
  port     = 5433
  user     = "yugabyte"
  password = "yugabyte"
  dbname   = "yugabyte"
)

func main() {
    psqlInfo := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s",
                            host, port, user, password, dbname)
    // Other connection configs are read from the standard environment variables:
    // PGSSLMODE, PGSSLROOTCERT, and so on.
    db, err := sql.Open("postgres", psqlInfo)
    if err != nil {
        log.Fatal(err)
    }

    var dropStmt = `DROP TABLE IF EXISTS employee`;
    if _, err := db.Exec(dropStmt); err != nil {
        log.Fatal(err)
    }

    var createStmt = `CREATE TABLE employee (id int PRIMARY KEY,
                                             name varchar,
                                             age int,
                                             language varchar)`;
    if _, err := db.Exec(createStmt); err != nil {
        log.Fatal(err)
    }
    fmt.Println("Created table employee")

    // Insert into the table.
    var insertStmt string = "INSERT INTO employee(id, name, age, language)" +
        " VALUES (1, 'John', 35, 'Go')";
    if _, err := db.Exec(insertStmt); err != nil {
        log.Fatal(err)
    }
    fmt.Printf("Inserted data: %s\n", insertStmt)

    // Read from the table.
    var name string
    var age int
    var language string
    rows, err := db.Query(`SELECT name, age, language FROM employee WHERE id = 1`)
    if err != nil {
        log.Fatal(err)
    }
    defer rows.Close()
    fmt.Printf("Query for id=1 returned: ");
    for rows.Next() {
        err := rows.Scan(&name, &age, &language)
        if err != nil {
           log.Fatal(err)
        }
        fmt.Printf("Row[%s, %d, %s]\n", name, age, language)
    }
    err = rows.Err()
    if err != nil {
        log.Fatal(err)
    }

    defer db.Close()
}

The const values are set to the defaults for a local installation of YugabyteDB. If you are using Yugabyte Cloud, replace the const values in the file as follows:

host - The host address of your cluster. The host address is displayed on the cluster Settings tab.
user - Your Yugabyte database username. In Yugabyte Cloud, the default user is admin.
password - Your Yugabyte database password.
dbname - The name of the Yugabyte database. The default Yugabyte database name is yugabyte.

port is set to 5433, which is the default port for the YSQL API.

For a Yugabyte Cloud cluster or a YugabyteDB cluster with SSL/TLS enabled, set the SSL-related environment variables as below.

 $ export PGSSLMODE=verify-ca
 $ export PGSSLROOTCERT=~/root.crt  # Here, the CA certificate file is downloaded as `root.crt` under home directory. Modify your path accordingly.

Run the application

$ go run ybsql_hello_world.go

You should see the following output.

Created table employee
Inserted data: INSERT INTO employee(id, name, age, language) VALUES (1, 'John', 35, 'Go')
Query for id=1 returned: Row[John, 35, Go]

Build a Go application

Prerequisites

SSL/TLS configuration

CA certificate

OpenSSL

Go PostgreSQL driver

Create the sample Go application

Set SSL/TLS related variables

Run the application