Project: YugabyteDB (App Definition and Development / Database)
File: cloud-ysql-go.md

title: Build a Go application that uses YSQL headerTitle: Build a Go application linkTitle: Go description: Build a simple Go application using the Go PostgreSQL driver and using the YSQL API to connect to and interact with a YugabyteDB Managed cluster. headContent: "Client driver: Go PostgreSQL" menu: v2.18: parent: build-apps name: Go identifier: cloud-go weight: 200 type: docs The following tutorial shows a small that connects to a YugabyteDB cluster using the and performs basic SQL operations. Use the application as a template to get started with YugabyteDB Managed in Go. (tested with version 1.17.6). Clone the sample application to your computer: ```sh git clone https://github.com/YugabyteDB-Samples/yugabyte-simple-go-app.git && cd yugabyte-simple-go-app ``` If your cluster is running on YugabyteDB Managed, you need to modify the connection parameters so that the application can establish a connection to the YugabyteDB cluster. (You can skip this step if your cluster is running locally and listening on 127.0.0.1:5433.) To do this: Open the `sample-app.go` file. Set the following configuration parameter constants: host - the host name of your YugabyteDB cluster. For local clusters, use the default (127.0.0.1). For YugabyteDB Managed, select your cluster on the Clusters page, and click Settings. The host is displayed under Connection Parameters. port - the port number for the driver to use (the default YugabyteDB YSQL port is 5433). dbName - the name of the database you are connecting to (the default is `yugabyte`). dbUser and dbPassword - the username and password for the YugabyteDB database. For local clusters, use the defaults (`yugabyte` and `yugabyte`). For YugabyteDB Managed, use the credentials in the credentials file you downloaded. sslMode - the SSL mode to use. YugabyteDB Managed ; use `verify-full`. sslRootCert - the full path to the YugabyteDB Managed cluster CA certificate. Save the file. First, initialize the `GO111MODULE` variable. ```sh $ export GO111MODULE=auto ``` Import the Go PostgreSQL driver. ```sh $ go get github.com/lib/pq ``` Start the application. ```sh $ go run sample-app.go ``` You should see output similar to the following: ```output >>> Successfully connected to YugabyteDB! >>> Successfully created table

>>> Selecting accounts: name = Jessica, age = 28, country = USA, balance = 10000 name = John, age = 28, country = Canada, balance = 9000 >>> Transferred 800 between accounts. >>> Selecting accounts: name = Jessica, age = 28, country = USA, balance = 9200 name = John, age = 28, country = Canada, balance = 9800 ``` You have successfully executed a basic Go application that works with YugabyteDB Managed. Open the `sample-app.go` file in the `yugabyte-simple-go-app` folder to review the methods. The `main` method establishes a connection with your cluster via the Go PostgreSQL driver. ```go psqlInfo := fmt.Sprintf("host=%s port=%d user=%s password=%s dbname=%s", host, port, dbUser, dbPassword, dbName) if sslMode != "" { psqlInfo += fmt.Sprintf(" sslmode=%s", sslMode) if sslRootCert != "" { psqlInfo += fmt.Sprintf(" sslrootcert=%s", sslRootCert) } } db, err := sql.Open("postgres", psqlInfo) ``` The `createDatabase` method uses PostgreSQL-compliant DDL commands to create a sample database. ```go Statement stmt = conn.createStatement(); stmt := `DROP TABLE IF EXISTS DemoAccount` _, err := db.Exec(stmt) checkIfError(err) stmt = `CREATE TABLE DemoAccount ( id int PRIMARY KEY, name varchar, age int, country varchar, balance int)` _, err = db.Exec(stmt) checkIfError(err) stmt = `INSERT INTO DemoAccount VALUES (1, 'Jessica', 28, 'USA', 10000), (2, 'John', 28, 'Canada', 9000)` _, err = db.Exec(stmt) checkIfError(err) ``` The `selectAccounts` method queries your distributed data using the SQL `SELECT` statement. ```go rows, err := db.Query("SELECT name, age, country, balance FROM DemoAccount") checkIfError(err) defer rows.Close() var name, country string var age, balance int for rows.Next() { err = rows.Scan(&name, &age, &country, &balance) checkIfError(err) fmt.Printf("name = %s, age = %v, country = %s, balance = %v\n", name, age, country, balance) } ``` The `transferMoneyBetweenAccounts` method updates your data consistently with distributed transactions. ```go tx, err := db.Begin() checkIfError(err) _, err = tx.Exec(`UPDATE DemoAccount SET balance = balance - $1 WHERE name = 'Jessica'`, amount) if checkIfTxAborted(err) { return } _, err = tx.Exec(`UPDATE DemoAccount SET balance = balance + $1 WHERE name = 'John'`, amount) if checkIfTxAborted(err) { return } err = tx.Commit() if checkIfTxAborted(err) { return } ```