Use the Go client library to connect to Spanner Omni

This document shows you how to establish secure connections to Spanner Omni by configuring the Go client library. You establish these connections by setting client options when you create a database administrative client or a database client.

The Go client library supports plain text, TLS, and mTLS connections. For all connection types, include option.WithoutAuthentication() to prevent transmitting Google Cloud credentials to a Spanner Omni endpoint.

For more information, see Getting started with Spanner in Go in the Spanner documentation.

Before you begin

To connect the Go client library to Spanner Omni, you need to use the IsExperimentalHost: true configuration. This option specifies that the library connects to a local or on-premises deployment of Spanner Omni rather than the managed version of Spanner.

To use this configuration option, your environment must meet the following requirements:

The Go client library must be version v1.91.0 or later.
The Go release must be version 1.25 or later.

Plain-text communication

To establish plain-text communication, run the following code:

import ("google.golang.org/grpc/credentials/insecure")

adminClient, err := database.NewDatabaseAdminClient(ctx,
    option.WithEndpoint(OMNI_ENDPOINT),
option.WithoutAuthentication(),
option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
)

clientConfig := ClientConfig{
        IsExperimentalHost: true,
    }
databaseClient, err := spanner.NewClientWithConfig(ctx, db,
clientConfig,
    option.WithEndpoint(OMNI_ENDPOINT),
option.WithoutAuthentication(),
option.WithGRPCDialOption(grpc.WithTransportCredentials(insecure.NewCredentials())),
)

TLS connection

To establish a TLS connection, run the following code:

func createClients(ca_certificate, database, omniEndpoint string){
    // TLS CA cert configuration
caCert, err := os.ReadFile(ca_certificate)
    capool := x509.NewCertPool()
capool.AppendCertsFromPEM(caCert)
    creds := credentials.NewTLS(&tls.Config{RootCAs: capool})

    adminClient, err := database.NewDatabaseAdminClient(ctx,
        option.WithEndpoint(omniEndpoint),
option.WithGRPCDialOption(grpc.WithTransportCredentials(creds)),
option.WithoutAuthentication(),
)
clientConfig := ClientConfig{
        IsExperimentalHost: true,
    }
databaseClient, err := spanner.NewClientWithConfig(ctx, db,
clientConfig,
        option.WithEndpoint(omniEndpoint),
option.WithoutAuthentication(),
option.WithGRPCDialOption(grpc.WithTransportCredentials(creds)),
)
}

mTLS connection

To establish an mTLS connection, run the following code:

func createClients(ca_certificate, client_certificate, client_key, database, omniEndpoint string){
    // mTLS cred configuration
    caCert, err := os.ReadFile(ca_certificate)
        capool := x509.NewCertPool()
        capool.AppendCertsFromPEM(caCert)
        cert := tls.LoadX509KeyPair(client_certificate, client_key)
        creds := credentials.NewTLS(&tls.Config{Certificates: []tls.Certificate{cert}, RootCAs: capool})

        adminClient, err := database.NewDatabaseAdminClient(ctx,
            option.WithEndpoint(omniEndpoint),
            option.WithoutAuthentication(),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(creds))
    )
    clientConfig := ClientConfig{
            IsExperimentalHost: true,
        }
    databaseClient, err := spanner.NewClientWithConfig(ctx, db,
    clientConfig,
            option.WithEndpoint(omniEndpoint),
    option.WithoutAuthentication(),
    option.WithGRPCDialOption(grpc.WithTransportCredentials(creds)),
    )
}