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Connect a Go application to PlanetScale

Spin up a PlanetScale MySQL serverless database in seconds and connect to a Go application

Introduction

In this tutorial, you'll learn how to connect a Go application to a PlanetScale MySQL database using a sample Go starter app with GORM.

Prerequisites

Set up the Go app

This guide will integrate a simple Go (Golang) app with PlanetScale that will display a list of products stored in the database. If you have an existing application, you can also use that.

  1. Clone the starter Go application:
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git clone https://github.com/planetscale/golang-example.git
  1. Enter into the folder:
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cd golang-example
  1. Copy the .env.example file into .env:
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cp .env.example .env

Set up the database

Next, you need to set up your PlanetScale database and connect to it in the Go application.

You can create a database in the PlanetScale dashboard or from the PlanetScale CLI. This guide will use the CLI, but you can follow the database setup instructions in the PlanetScale quickstart guide if you prefer the dashboard.

  1. Authenticate the CLI with the following command:
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pscale auth login
  1. Create a new database with a default main branch with the following command:
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pscale database create <DATABASE_NAME> --region <REGION_SLUG>

For DATABASE_NAME, you can use any name with lowercase, alphanumeric characters, and dashes or underscores.

For REGION_SLUG, choose a region closest to you from the available regions or leave it blank.

That's it! Your database is ready to use. Next, let's connect it to the Go application and then add some data.

Connect to the Go app

There are two ways to connect your Go app to PlanetScale:

  • With an auto-generated username and password
  • Using the PlanetScale proxy with the CLI

Both options are covered below.

Option 1: Connect with username and password (Recommended)

  1. Create a username and password with the PlanetScale CLI by running:
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pscale password create <DATABASE_NAME> <BRANCH_NAME> <PASSWORD_NAME>

A default branch, main, is created when you create the database, so you can use that for BRANCH_NAME.

Note

The PASSWORD_NAME value represents the name of the username and password being generated. You can have multiple credentials for a branch, so this gives you a way to categorize them. To manage your passwords in the dashboard, go to your database overview page, click "Settings", and then click "Passwords".

Take note of the values returned to you, as you won't be able to see this password again.

  1. Open the .env file in your Go app and update DSN as follows:
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DSN="mysql://<USERNAME>:<PASSWORD>@tcp(<ACCESS HOST URL>)/<DATABASE_NAME>?tls=true"

Fill in USERNAME, PASSWORD, ACCESS HOST URL, and DATABASE_NAME with the appropriate values from the CLI output above. Do not remove the parentheses around the access host URL.

You can also get these exact values to copy/paste from your PlanetScale dashboard. In the dashboard, click on the database > "Connect" > "Connect with" language dropdown > "Go".

Option 2: Connect with the PlanetScale proxy

To connect with the PlanetScale proxy, you need the PlanetScale CLI.

  1. Open a connection by running the following:
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pscale connect <DATABASE_NAME> <BRANCH_NAME>

If you're following this guide exactly and haven't created any branches, you can use the default branch, main.

  1. A secure connection to your database will be established, and you'll see a local address you can use to connect to your application.

  2. Open the .env file in your Go app and update it as follows:

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DSN="mysql://root@tcp(127.0.0.1:<PORT>)/<DATABASE_NAME>"

The connection uses port 3306 by default, but if that's being used, it will pick a random port. Make sure you paste in whatever port is returned in the terminal. Fill in the database name as well.

Run migrations and seeder

Now that you're connected let's add some data to see it in action. The sample application has an endpoint that you can use to run migrations to create your categories and products tables. It will seed your database with sample product and category data. You can find this in main.go.

Let's run those now.

  1. First, start your Go app with:
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go run .
  1. Next, navigate to localhost:8080/seed to run the migrations and the seeder.

  2. You can now see the products and categories:

Foreign key constraints

If you're using GORM in your Go application, take note of this line in the main.go file of the Go starter application:

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// ...
DisableForeignKeyConstraintWhenMigrating: true,
// ...

PlanetScale does not support foreign key constraints, but we do support the use of relationships with foreign keys, as shown in this example. For more information, check out our Operating without foreign key constraints documentation.

Add data manually

If you want to continue to play around with adding data on the fly, you have a few options:

  • PlanetScale CLI shell
  • PlanetScale dashboard console
  • Your favorite MySQL client (E.g. Arctype, TablePlus, DataGrip, etc.)

The first two options are covered below.

Add data with PlanetScale CLI

You can use the PlanetScale CLI to open a MySQL shell to interact with your database.

You may need to install the MySQL command line client if you haven't already.

  1. Run the following command in your terminal:
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pscale shell <DATABASE_NAME> <BRANCH_NAME>

This will open up a MySQL shell connected to the specified database and branch.

Note

A branch, main, was automatically created when you created your database, so you can use that for BRANCH_NAME.

  1. Add a record to the products table:
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INSERT INTO `products` (name, description, image, category_id)
VALUES ('Spaceship', 'Get ready for the trip of a lifetime', 'https://via.placeholder.com/300.png', 2);

The value id will be filled with a default value.

  1. You can verify it was added in the PlanetScale CLI MySQL shell with:
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SELECT * FROM products;
  1. Type exit to exit the shell.

You can now navigated the Go products page to see the new record.

Add data with PlanetScale dashboard console

If you don't care to install MySQL client or the PlanetScale CLI, another quick option is using the MySQL console built into the PlanetScale dashboard.

PlanetScale console insert and select examplePlanetScale console insert and select example

  1. Go to your PlanetScale dashboard and select your Go database.
  2. Click on the "Branches and select the main branch.
  3. Click on "Console"
  4. Add a new record to the product table with:
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INSERT INTO `products` (name, description, image, category_id)
VALUES ('Spaceship', 'Get ready for the trip of a lifetime', 'https://via.placeholder.com/300.png', 2);
  1. You can confirm that it was added by running:
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SELECT * FROM products;

You can now refresh the Go products page to see the new record.

What's next?

Once you're done with development, you can promote your main branch to production to get a highly available branch protected by direct schema changes.

When you're reading to make more schema changes, you'll create a new branch off of your production branch. Branching your database creates an isolated copy of your production schema so that you can easily test schema changes in development. Once you're happy with the changes, you'll open a deploy request. This will generate a diff showing the changes that will be deployed, making it easy for your team to review.

Learn more about how PlanetScale allows you to make non-blocking schema changes to your database tables without locking or causing downtime for production databases.

Need help?

Get help from PlanetScale's support team, or join our GitHub Discussion board to see how others are using PlanetScale.

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Last updated on May 3, 2022
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