Go driver

To use the Apache Cassandra® GoCQL driver (gocql) with Astra DB, use the gocql-astra package, which includes gocql and additional support for connections to Astra DB.

Because gocql doesn’t directly support connections to Astra DB, the gocql-astra package provides a custom gocql.HostDialer that facilitates gocql connections to Astra DB.

This guide explains how to use gocql-astra to connect gocql to your database, create a table, read and write data, and then delete the rows and table.

Prerequisites

An active Astra account.
An active Astra DB Classic database.
Install Go version 1.18 or later.

Install gocql-astra

In the root of your Go project directory, add gocql-astra:

go get github.com/datastax/gocql-astra

gocql-astra includes the gocql dependency.

Connect to your database

gocql-astra provides support to connect gocql to Astra DB.

Connect with an application token
Connect with an SCB

Set the following environment variables:
- ASTRA_DB_ID: The database ID
- ASTRA_DB_REGION: A region where your database is deployed and where you want to connect to the database, such as us-east-2
- ASTRA_DB_KEYSPACE: A keyspace in your database, such as default_keyspace
- ASTRA_DB_APPLICATION_TOKEN: An application token with the Database Administrator role.

Run a script such as the following to connect to your database. This code imports the necessary classes, sets up a session, authenticates with an application token, and specifies a default keyspace.

package main

import (
    "fmt"
    "log"
    "os"
    "time"

    gocqlastra "github.com/datastax/gocql-astra"
    "github.com/gocql/gocql"
)

func main() {

    var err error

    var cluster *gocql.ClusterConfig

    if len(os.Getenv("ASTRA_DB_APPLICATION_TOKEN")) > 0 {

        if len(os.Getenv("ASTRA_DB_ID")) == 0 {
            panic("database ID is required when using a token")
        }
    }

    cluster, err = gocqlastra.NewClusterFromURL("https://api.astra.datastax.com", os.Getenv("ASTRA_DB_ID"), os.Getenv("ASTRA_DB_APPLICATION_TOKEN"), 10*time.Second)

    if err != nil {
        log.Fatalf("unable to load cluster %s from astra: %v", os.Getenv("ASTRA_DB_APPLICATION_TOKEN"), err)
    }

    cluster.Timeout = 30 * time.Second
    start := time.Now()
    session, err := gocql.NewSession(*cluster)
    elapsed := time.Now().Sub(start)

    if err != nil {
        log.Fatalf("unable to connect session: %v", err)
    }

    fmt.Println("Making the query now")

    iter := session.Query("SELECT release_version FROM system.local").Iter()

    var version string

    for iter.Scan(&version) {
        fmt.Println(version)
    }

    if err = iter.Close(); err != nil {
        log.Printf("error running query: %v", err)
    }

    fmt.Printf("Connection process took %s
", elapsed)

    if err != nil {
        log.Fatalf("unable to connect session: %v", err)
    }

}

Download your database’s Secure Connect Bundle (SCB).
Set the following environment variables:
- ASTRA_DB_SECURE_BUNDLE_PATH: The path your database’s SCB ZIP file.
- ASTRA_DB_APPLICATION_TOKEN: An application token with the Database Administrator role.

Run a script such as the following to connect to your database. This code imports the necessary classes, sets up a session, and authenticates with an SCB.

package main

import (
    "fmt"
    "log"
    "os"
    "time"

    gocqlastra "github.com/datastax/gocql-astra"
    "github.com/gocql/gocql"
)

func main() {

    var cluster *gocql.ClusterConfig

    cluster, err := gocqlastra.NewClusterFromBundle(os.Getenv("ASTRA_DB_SECURE_BUNDLE_PATH"),
        "token", os.Getenv("ASTRA_DB_APPLICATION_TOKEN"), 30*time.Second)

    if err != nil {
        panic("unable to load the bundle")
    }
    cluster.Timeout = 30 * time.Second

    session, err := gocql.NewSession(*cluster)

    if err != nil || session == nil {
        log.Fatalf("unable to connect session: %v", err)
    } else {
        fmt.Println("Success!")
    }

}

Run commands

With gocql-astra, your scripts can use gocql commands to perform operations on your database.

For example, the following sample script performs these operations:

Defines the Book object
Connects to the database with an application token
Create a books table
Inserts two rows into the table
Retries the inserted rows
Updates one row
Deletes one row
Deletes the table

main.go

package main

import (
    "fmt"
    "log"
    "os"
    "time"

    gocqlastra "github.com/datastax/gocql-astra"
    "github.com/gocql/gocql"
)

type Book struct {
    ID     gocql.UUID
    Title  string
    Author string
    Year   int
}

func main() {

    var err error

    var cluster *gocql.ClusterConfig

    if len(os.Getenv("ASTRA_DB_APPLICATION_TOKEN")) > 0 {
        if len(os.Getenv("ASTRA_DB_ID")) == 0 {
            panic("database ID is required when using a token")
        }
    }

    fmt.Println("Creating the cluster now")

    cluster, err = gocqlastra.NewClusterFromURL("https://api.astra.datastax.com", os.Getenv("ASTRA_DB_ID"), os.Getenv("ASTRA_DB_APPLICATION_TOKEN"), 20*time.Second)
    if err != nil {
        log.Fatalf("unable to load cluster %s from astra: %v", os.Getenv("ASTRA_DB_APPLICATION_TOKEN"), err)
    }
    cluster.Timeout = 30 * time.Second
    session, err := gocql.NewSession(*cluster)

    if err != nil {
        log.Fatalf("unable to connect session: %v", err)
    }

    defer session.Close()

    // Delete the table
    if err := session.Query(`DROP TABLE IF EXISTS library.books`).Exec(); err != nil {
        fmt.Println("Dropping table to clean for examples.")
    }

    // Create the table
    fmt.Println("Creating the table now")
    if err := session.Query(`CREATE TABLE library.books ( id uuid PRIMARY KEY, title text, author text, year int );`).Exec(); err != nil {
        log.Fatal(err)
    }
    // Create Rows
    newBook := Book{
        ID:     gocql.TimeUUID(),
        Title:  "Go Programming",
        Author: "John Doe",
        Year:   2023,
    }

    secondBook := Book{
        ID:     gocql.TimeUUID(),
        Title:  "Zen and the Art of Go",
        Author: "Jane Doe",
        Year:   2023,
    }

    fmt.Println("Adding the books now:")

    if err := session.Query(`INSERT INTO library.books (id, title, author, year) VALUES (?, ?, ?, ?)`,
        newBook.ID, newBook.Title, newBook.Author, newBook.Year).Exec(); err != nil {
        log.Fatal(err)
    }

    if err := session.Query(`INSERT INTO library.books (id, title, author, year) VALUES (?, ?, ?, ?)`,
        secondBook.ID, secondBook.Title, secondBook.Author, secondBook.Year).Exec(); err != nil {
        log.Fatal(err)
    }

    fmt.Println("Querying the books now:")
    iter := session.Query(`SELECT id, title, author, year FROM library.books`).Iter()

    var books []Book
    var book Book
    for iter.Scan(&book.ID, &book.Title, &book.Author, &book.Year) {
        books = append(books, book)
    }

    if err := iter.Close(); err != nil {
        log.Fatal(err)
    }

    // Print all books
    for _, book := range books {
        fmt.Println("Book:", book)
    }

    // Update
    updatedBook := Book{
        ID:     newBook.ID,
        Title:  "Advanced Go Programming",
        Author: "John Doe",
        Year:   2024,
    }

    if err := session.Query(`UPDATE library.books SET title = ?, author = ?, year = ? WHERE id = ?`,
        updatedBook.Title, updatedBook.Author, updatedBook.Year, updatedBook.ID).Exec(); err != nil {
        log.Fatal(err)
    }

    // Delete
    if err := session.Query(`DELETE FROM library.books WHERE id = ?`, newBook.ID).Exec(); err != nil {
        log.Fatal(err)
    }

}

To run the sample script:

In your Go project directory, create a main.go file.
Copy the sample script to main.go, and then save the file.
Run main.go.

Be aware that the sample script creates and deletes a table. If you run it as is, the books table won’t exist in your database after the script ends. Consider breaking the sample script into smaller scripts or commenting out the DELETE commands if you want to preserve the books table for additional testing.
```
go run main.go
```

Go driver

Prerequisites

Install gocql-astra

Connect to your database

Run commands

See also

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