db.go

package main

import (
	"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"
)

// Declare a new DynamoDB instance. Note that this is safe for concurrent
// use.
var db = dynamodb.New(session.New(), aws.NewConfig().WithRegion("eu-west-2"))

func getItem(id string) (*user, error) {
	// Prepare the input for the query.
	input := &dynamodb.GetItemInput{
		TableName: aws.String("Users"),
		Key: map[string]*dynamodb.AttributeValue{
			"ID": {
				S: aws.String(id),
			},
		},
	}

	// Retrieve the item from DynamoDB. If no matching item is found
	// return nil.
	result, err := db.GetItem(input)
	if err != nil {
		return nil, err
	}
	if result.Item == nil {
		return nil, nil
	}

	// The result.Item object returned has the underlying type
	// map[string]*AttributeValue. We can use the UnmarshalMap helper
	// to parse this straight into the fields of a struct. Note:
	// UnmarshalListOfMaps also exists if you are working with multiple
	// items.
	u := new(user)
	err = dynamodbattribute.UnmarshalMap(result.Item, u)
	if err != nil {
		return nil, err
	}

	return u, nil
}

func putItem(u *user) error {

	input := &dynamodb.PutItemInput{
		TableName: aws.String("Users"),
		Item: map[string]*dynamodb.AttributeValue{
			"ID": {
				S: aws.String(u.ID),
			},
			"Name": {
				S: aws.String(u.Name),
			},
			"Hobbies": {
				S: aws.String(u.Hobbies),
			},
		},
	}

	_, err := db.PutItem(input)
	return err

}