Go

Examples on GitHub: sample_db, go

go-tarantool is the official Go connector for Tarantool. It is not supplied as part of the Tarantool repository and should be installed separately.

This tutorial shows how to use the go-tarantool 2.x library to create a Go application that connects to a remote Tarantool instance, performs CRUD operations, and executes a stored procedure. You can find the full package documentation here: Client in Go for Tarantool.

Before creating and starting a client Go application, you need to run the sample_db application using tt start:

 
$ tt start sample_db

Now you can create a client Go application that makes requests to this database.

Before you start, make sure you have Go installed on your computer.

1. Create the hello directory for your application and go to this directory:

    
   $ mkdir hello$ cd hello

2. Initialize a new Go module:

    
   $ go mod init example/hello

3. Inside the hello directory, create the hello.go file for application code.

In the hello.go file, declare a main package and import the following packages:

 
package mainimport (	"context"	"fmt"	"github.com/tarantool/go-tarantool/v2"	_ "github.com/tarantool/go-tarantool/v2/datetime"	_ "github.com/tarantool/go-tarantool/v2/decimal"	_ "github.com/tarantool/go-tarantool/v2/uuid"	"time")

The packages for external MsgPack types, such as datetime, decimal, or uuid, are required to parse these types in a response.

1. Declare the main() function:

    
   func main() {}

2. Inside the main() function, add the following code:

 
// Connect to the databasectx, cancel := context.WithTimeout(context.Background(), time.Second)defer cancel()dialer := tarantool.NetDialer{	Address:  "127.0.0.1:3301",	User:     "sampleuser",	Password: "123456",}opts := tarantool.Opts{	Timeout: time.Second,}conn, err := tarantool.Connect(ctx, dialer, opts)if err != nil {	fmt.Println("Connection refused:", err)	return}// Interact with the database// ...

 
This code establishes a connection to a running Tarantool instanceon behalf of `sampleuser`. The `conn` object can be used to makeCRUD requests and execute stored procedures.

Add the following code to insert four tuples into the bands space:

 
// Insert datatuples := [][]interface{}{	{1, "Roxette", 1986},	{2, "Scorpions", 1965},	{3, "Ace of Base", 1987},	{4, "The Beatles", 1960},}var futures []*tarantool.Futurefor _, tuple := range tuples {	request := tarantool.NewInsertRequest("bands").Tuple(tuple)	futures = append(futures, conn.Do(request))}fmt.Println("Inserted tuples:")for _, future := range futures {	result, err := future.Get()	if err != nil {		fmt.Println("Got an error:", err)	} else {		fmt.Println(result)	}}

This code makes insert requests asynchronously:

• The Future structure is used as a handle for asynchronous requests.
• The NewInsertRequest() method creates an insert request object that is executed by the connection.

To get a tuple by the specified primary key value, use NewSelectRequest() to create an insert request object:

 
// Select by primary keydata, err := conn.Do(	tarantool.NewSelectRequest("bands").		Limit(10).		Iterator(tarantool.IterEq).		Key([]interface{}{uint(1)}),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Tuple selected by the primary key value:", data)

You can also get a tuple by the value of the specified index by using Index():

 
// Select by secondary keydata, err = conn.Do(	tarantool.NewSelectRequest("bands").		Index("band").		Limit(10).		Iterator(tarantool.IterEq).		Key([]interface{}{"The Beatles"}),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Tuple selected by the secondary key value:", data)

NewUpdateRequest() can be used to update a tuple identified by the primary key as follows:

 
// Updatedata, err = conn.Do(	tarantool.NewUpdateRequest("bands").		Key(tarantool.IntKey{2}).		Operations(tarantool.NewOperations().Assign(1, "Pink Floyd")),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Updated tuple:", data)

NewUpsertRequest() can be used to update an existing tuple or insert a new one. In the example below, a new tuple is inserted:

 
// Upsertdata, err = conn.Do(	tarantool.NewUpsertRequest("bands").		Tuple([]interface{}{uint(5), "The Rolling Stones", 1962}).		Operations(tarantool.NewOperations().Assign(1, "The Doors")),).Get()if err != nil {	fmt.Println("Got an error:", err)}

In this example, NewReplaceRequest() is used to delete the existing tuple and insert a new one:

 
// Replacedata, err = conn.Do(	tarantool.NewReplaceRequest("bands").		Tuple([]interface{}{1, "Queen", 1970}),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Replaced tuple:", data)

NewDeleteRequest() in the example below is used to delete a tuple whose primary key value is 5:

 
// Deletedata, err = conn.Do(	tarantool.NewDeleteRequest("bands").		Key([]interface{}{uint(5)}),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Deleted tuple:", data)

To execute a stored procedure, use NewCallRequest():

 
// Calldata, err = conn.Do(	tarantool.NewCallRequest("get_bands_older_than").Args([]interface{}{1966}),).Get()if err != nil {	fmt.Println("Got an error:", err)}fmt.Println("Stored procedure result:", data)

The CloseGraceful() method can be used to close the connection when it is no longer needed:

 
// Close connectionconn.CloseGraceful()fmt.Println("Connection is closed")

1. Execute the following go get commands to update dependencies in the go.mod file:

    
   $ go get github.com/tarantool/go-tarantool/v2$ go get github.com/tarantool/go-tarantool/v2/decimal$ go get github.com/tarantool/go-tarantool/v2/uuid

2. To run the resulting application, execute the go run command in the application directory:

    
   $ go run .Inserted tuples:[[1 Roxette 1986]][[2 Scorpions 1965]][[3 Ace of Base 1987]][[4 The Beatles 1960]]Tuple selected by the primary key value: [[1 Roxette 1986]]Tuple selected by the secondary key value: [[4 The Beatles 1960]]Updated tuple: [[2 Pink Floyd 1965]]Replaced tuple: [[1 Queen 1970]]Deleted tuple: [[5 The Rolling Stones 1962]]Stored procedure result: [[[2 Pink Floyd 1965] [4 The Beatles 1960]]]Connection is closed

Last update: January 2023

There are also the following community-driven Go connectors:

• viciious/go-tarantool
• FZambia/tarantool

The table below contains a feature comparison for the connectors mentioned above.