Using BatchGetItem to fetch

company_fetch.go

func (d *DynamoDBCompanyRepository) GetCompanies(ctx context.Context, companyIds []string) ([]models.Company, error) {
	var keys []map[string]*dynamodb.AttributeValue

	for _, c := range companyIds {
		key := models.GetCompanyKey(c)
		m := map[string]*dynamodb.AttributeValue{
			"PK": {
				S: aws.String(key),
			},
			"SK": {
				S: aws.String(key),
			},
		}
		keys = append(keys, m)
	}

	input := &dynamodb.BatchGetItemInput{
		RequestItems: map[string]*dynamodb.KeysAndAttributes{
			d.tableName: {
				Keys: keys,
			},
		},
	}

	log.WithFields(log.Fields{
		"input":         input,
	}).Debug("The query input")

	var companies []models.Company
	err := d.db.BatchGetItemPagesWithContext(
		ctx, input,
		func(page *dynamodb.BatchGetItemOutput, lastPage bool) bool {
			for _, v := range page.Responses {
				for _, v2 := range v {
					var c models.Company
					_ = dynamodbattribute.UnmarshalMap(v2, &c)
					companies = append(companies, c)
				}
			}

			return lastPage
		})

	if err != nil {
		return nil, err
	}

	return companies, nil
}