Creating a Go-Based Application for AWS DynamoDB Management

Table of Contents

1. Introduction
2. Prerequisites
3. Setting Up AWS Credentials
4. Installing the AWS SDK for Go
5. Creating a New DynamoDB Table
6. Adding Items to the Table
7. Retrieving Items from the Table
8. Updating Items in the Table
9. Deleting Items from the Table
10. Conclusion

Introduction

In this tutorial, we will learn how to create a Go-based application for managing AWS DynamoDB. DynamoDB is a fully-managed NoSQL database service provided by Amazon Web Services (AWS). By the end of this tutorial, you will be able to perform CRUD (Create, Read, Update, Delete) operations on a DynamoDB table using Go.

Prerequisites

Before you begin, ensure that you have the following prerequisites:

1. Go installed on your machine

2. An AWS account with access to DynamoDB

3. AWS CLI installed and configured with your AWS credentials

Setting Up AWS Credentials

To interact with DynamoDB, you need to set up your AWS credentials. Follow these steps:

1. Open the AWS Management Console and go to the IAM service.
2. Click on “Users” in the left navigation pane and then click on your username.

3. Go to the “Security credentials” tab and click on “Create access key”.

4. Save the generated access key ID and secret access key in a secure location.

   Next, configure the AWS CLI by running the following command in your terminal:

    aws configure
   

   Enter your AWS access key ID, secret access key, default region, and default output format when prompted.

Installing the AWS SDK for Go

To use Go to interact with DynamoDB, we need to install the AWS SDK for Go. Run the following command to install it:

go get github.com/aws/aws-sdk-go/aws
go get github.com/aws/aws-sdk-go/aws/session
go get github.com/aws/aws-sdk-go/service/dynamodb

Creating a New DynamoDB Table

Now let’s create a new DynamoDB table using Go. Open your favorite text editor and create a new file called main.go. Add the following code to the file:

package main

import (
	"fmt"
	"github.com/aws/aws-sdk-go/aws"
	"github.com/aws/aws-sdk-go/aws/session"
	"github.com/aws/aws-sdk-go/service/dynamodb"
	"github.com/aws/aws-sdk-go/service/dynamodb/dynamodbattribute"
)

func main() {
	// Create an AWS session
	sess := session.Must(session.NewSession(&aws.Config{
		Region: aws.String("us-west-2"), // Replace with your desired region
	}))

	// Create a DynamoDB service client
	svc := dynamodb.New(sess)

	// Define the table schema
	tableName := "Books"
	keyName := "ISBN"

	// Create the table
	_, err := svc.CreateTable(&dynamodb.CreateTableInput{
		AttributeDefinitions: []*dynamodb.AttributeDefinition{
			{
				AttributeName: aws.String(keyName),
				AttributeType: aws.String("N"), // N represents a number
			},
		},
		KeySchema: []*dynamodb.KeySchemaElement{
			{
				AttributeName: aws.String(keyName),
				KeyType:       aws.String("HASH"), // HASH represents the primary key
			},
		},
		ProvisionedThroughput: &dynamodb.ProvisionedThroughput{
			ReadCapacityUnits:  aws.Int64(5),
			WriteCapacityUnits: aws.Int64(5),
		},
		TableName: aws.String(tableName),
	})

	// Check for errors
	if err != nil {
		fmt.Println("Error creating table:", err.Error())
		return
	}

	fmt.Println("Table created successfully!")
}

Make sure to replace us-west-2 with your desired region. This code creates a new DynamoDB table named “Books” with an attribute “ISBN” as the primary key.

To run the code, open your terminal and navigate to the directory where main.go is located. Execute the following command:

go run main.go

If everything is set up correctly, you should see the message “Table created successfully!”.

Adding Items to the Table

Now let’s add some items to the table we created. Add the following code to the main function in main.go:

// Define the item to be added
item := struct {
	ISBN   int    `json:"ISBN"`
	Title  string `json:"Title"`
	Author string `json:"Author"`
}{
	ISBN:   1234567890,
	Title:  "Golang for Beginners",
	Author: "John Doe",
}

// Convert the item to a DynamoDB attribute value map
av, err := dynamodbattribute.MarshalMap(item)
if err != nil {
	fmt.Println("Error marshaling item:", err.Error())
	return
}

// Create the input to add the item
input := &dynamodb.PutItemInput{
	Item:      av,
	TableName: aws.String(tableName),
}

_, err = svc.PutItem(input)
if err != nil {
	fmt.Println("Error adding item:", err.Error())
	return
}

fmt.Println("Item added to the table!")

This code defines an item with an ISBN, title, and author, and then adds it to the DynamoDB table. Replace the values with your desired item information.

Run the code again with go run main.go. You should see the message “Item added to the table!”.

Retrieving Items from the Table

Let’s retrieve an item from the table. Add the following code to the main function in main.go:

// Create the input to retrieve the item
input := &dynamodb.GetItemInput{
	Key: map[string]*dynamodb.AttributeValue{
		keyName: {
			N: aws.String("1234567890"),
		},
	},
	TableName: aws.String(tableName),
}

result, err := svc.GetItem(input)
if err != nil {
	fmt.Println("Error retrieving item:", err.Error())
	return
}

item := struct {
	ISBN   int    `json:"ISBN"`
	Title  string `json:"Title"`
	Author string `json:"Author"`
}{}

// Unmarshal the retrieved item into a struct
err = dynamodbattribute.UnmarshalMap(result.Item, &item)
if err != nil {
	fmt.Println("Error unmarshaling item:", err.Error())
	return
}

fmt.Println("Retrieved item:", item)

This code retrieves an item with a specified ISBN from the DynamoDB table. Replace the ISBN in the input with the one you added earlier.

Run the code again with go run main.go. You should see the retrieved item printed on the console.

Updating Items in the Table

Let’s update an item in the table. Add the following code to the main function in main.go:

// Create the input to update the item
input := &dynamodb.UpdateItemInput{
	ExpressionAttributeNames: map[string]*string{
		"#T": aws.String("Title"),
	},
	ExpressionAttributeValues: map[string]*dynamodb.AttributeValue{
		":t": {
			S: aws.String("Golang for Beginners - Updated"),
		},
	},
	Key: map[string]*dynamodb.AttributeValue{
		keyName: {
			N: aws.String("1234567890"),
		},
	},
	TableName: aws.String(tableName),
	UpdateExpression: aws.String("SET #T = :t"),
}

_, err = svc.UpdateItem(input)
if err != nil {
	fmt.Println("Error updating item:", err.Error())
	return
}

fmt.Println("Item updated successfully!")

This code updates the title of an item in the DynamoDB table. Replace the ISBN and title values in the code with the ones you added earlier.

Run the code again with go run main.go. You should see the message “Item updated successfully!”.

Deleting Items from the Table

Finally, let’s delete an item from the table. Add the following code to the main function in main.go:

// Create the input to delete the item
input := &dynamodb.DeleteItemInput{
	Key: map[string]*dynamodb.AttributeValue{
		keyName: {
			N: aws.String("1234567890"),
		},
	},
	TableName: aws.String(tableName),
}

_, err = svc.DeleteItem(input)
if err != nil {
	fmt.Println("Error deleting item:", err.Error())
	return
}

fmt.Println("Item deleted successfully!")

This code deletes an item with a specified ISBN from the DynamoDB table. Replace the ISBN in the input with the one you added earlier.

Run the code again with go run main.go. You should see the message “Item deleted successfully!”.

Conclusion

In this tutorial, we learned how to create a Go-based application for managing AWS DynamoDB. We covered creating a new DynamoDB table, adding items to the table, retrieving items from the table, updating items in the table, and deleting items from the table. By understanding these concepts and using the provided code examples, you can now start building your own Go-based applications using AWS DynamoDB.

Published: 13 July 2020

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