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Connect with Go

This example connects to an Aiven for Apache Cassandra® service from Go as the avnadmin user by making use of the gocql library.


These are the placeholders you will need to replace in the code sample:

HOSTHost name of your Cassandra service
PORTPort number used for connecting to your Cassandra service
USERUsername used for connecting to your Cassandra service. Defaults to avnadmin
PASSWORDPassword of the avnadmin user
SSL-CERTFILEPath to the CA Certificate file of your Cassandra service


Get the gocql library:

go get


  1. Create a file named main.go and add the following content:

    package main

    import (


    func main() {
    var args = parseArgs()

    type Args struct {
    Host string
    Port int
    Username string
    Password string
    SSLCertfile string

    func parseArgs() Args {
    var args Args
    flag.StringVar(&args.Host, "host", "", "Cassandra host")
    flag.IntVar(&args.Port, "port", -1, "Cassandra port")
    flag.StringVar(&args.Username, "user", "avnadmin", "Cassandra username")
    flag.StringVar(&args.Password, "password", "", "Cassandra password")
    flag.StringVar(&args.SSLCertfile, "ssl-certfile", "./ca.pem", "Path to project CA certificate")

    if args.Host == "" {
    fail("-host is required")
    } else if args.Port == -1 {
    fail("-port is required")
    } else if args.Password == "" {
    fail("-password is required")
    return args

    func fail(message string) {

    func cassandraExample(args Args) {
    var session = createSession(args)
    defer session.Close()

    func createSession(args Args) gocql.Session {
    cluster := gocql.NewCluster(args.Host)
    cluster.ConnectTimeout = 10 * time.Second
    cluster.Port = args.Port
    cluster.ProtoVersion = 4
    cluster.Authenticator = gocql.PasswordAuthenticator{
    Username: args.Username,
    Password: args.Password,
    cluster.SslOpts = &gocql.SslOptions{
    CaPath: args.SSLCertfile,
    cluster.Consistency = gocql.Quorum

    session, err := cluster.CreateSession()
    if err != nil {
    return *session

    func createSchema(session gocql.Session) {
    if err := session.Query(
    "CREATE KEYSPACE IF NOT EXISTS example_keyspace WITH REPLICATION = {'class': 'NetworkTopologyStrategy', 'aiven': 3}",
    ).Exec(); err != nil {
    if err := session.Query(
    "CREATE TABLE IF NOT EXISTS example_keyspace.example_go (id int PRIMARY KEY, message text)",
    ).Exec(); err != nil {

    func writeData(session gocql.Session) {
    if err := session.Query(
    "INSERT INTO example_keyspace.example_go (id, message) VALUES (?, ?)", 1, "hello world",
    ).Exec(); err != nil {

    func readData(session gocql.Session) {
    iter := session.Query("SELECT id, message FROM example_keyspace.example_go").Iter()
    var id int
    var message string
    for iter.Scan(&id, &message) {
    fmt.Printf("Row: id = %d, message = %s\n", id, message)
    if err := iter.Close(); err != nil {

    This code first creates a keyspace named example_keyspace and a table named example_go that contains an id and a message. Then, it writes a new entry into the table with the values 1. and hello world`. Finally, it reads the entry from the table and prints it.

  2. Execute the following from a terminal window to build an executable:

    go build main.go
  3. Run the program with the required flags to pass the necessary connection details:

    ./main --host <HOST> --port <PORT> --user avnadmin --password <PASSWORD> --ssl-certfile <PATH TO CERTFILE>