go dynamodb client

dynamodb.go

package main

import (
	"context"
	"fmt"
	"os"

	"github.com/aws/aws-sdk-go-v2/aws"
	"github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb"
	"github.com/aws/aws-sdk-go-v2/service/dynamodb/types"
)

type DynamoDBClient struct {
	client *dynamodb.Client
}

func New(endpointURL string) *DynamoDBClient {
	cfg, err := config.LoadDefaultConfig(context.Background())
	if err != nil {
		panic(err)
	}

	dynamodbEndpointResolver := getEndpointResolver(endpointURL)

	// Using the Config value, create the DynamoDB client.
	client := dynamodb.NewFromConfig(
		cfg,
		dynamodb.WithEndpointResolver(dynamodbEndpointResolver),
	)

	return &DynamoDBClient{client}
}

func main() {
	db := New(os.Getenv("DATABASE_AWS_DYNAMODB_ENDPOINT"))

	marshaledId, err := attributevalue.Marshal("0")
	if err != nil {
		panic(err)
	}

	resp, err := db.client.GetItem(context.Background(), &dynamodb.GetItemInput{
		Key:            map[string]types.AttributeValue{"id": marshaledId},
		TableName:      aws.String("test"),
		ConsistentRead: aws.Bool(true),
	})

	// var notFound *types.ResourceNotFoundException
	// if !errors.As(err, &notFound) {
	// 	panic(err)
	// }

	// for more information about struct tag `dynamodbav` check:
	// https://pkg.go.dev/github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue#Marshal
	if resp != nil {
		data := struct {
			ID   string `dynamodbav:"id"`
			Foo  string `dynamodbav:"foo"`
			Peon string `dynamodbav:"peon"`
		}{}
		attributevalue.UnmarshalMap(resp.Item, &data)

		fmt.Println(data)
	}
}

// getEndpointResolver returns the default endpoint if endpoint is empty
func getEndpointResolver(endpointURL string) dynamodb.EndpointResolver {
	if endpointURL != "" {
		return dynamodb.EndpointResolverFromURL(endpointURL)
	}
	return dynamodb.NewDefaultEndpointResolver()
}