sjauld/dynagodb

package dynagodb

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"
    "github.com/aws/aws-sdk-go/service/dynamodb/dynamodbiface"
)

// Backend provides a connection to dynamo
type Backend struct {
    Service   dynamodbiface.DynamoDBAPI
    TableName *string
}

// New returns a pointer to a Backend
func New(t string) *Backend {
    sess := session.New()
    return &Backend{
        Service:   dynamodb.New(sess),
        TableName: &t,
    }
}

// GetItem retrieves a go object from the table, using a consistent read
func (b *Backend) GetItem(v interface{}, key map[string]interface{}) error {
    var primaryKey = make(map[string]*dynamodb.AttributeValue)
    for k, val := range key {
        valAttr, err := dynamodbattribute.Marshal(val)
        if err != nil {
            return fmt.Errorf("Could not marshal primary key: %v", err)
        }
        primaryKey[k] = valAttr
    }
    in := &dynamodb.GetItemInput{
        ConsistentRead: aws.Bool(true),
        Key:            primaryKey,
        TableName:      b.TableName,
    }
    out, err := b.Service.GetItem(in)
    if err != nil {
        return fmt.Errorf("Could not GetItem from DynamoDB: %v", err)
    }

    err = dynamodbattribute.UnmarshalMap(out.Item, v)
    if err != nil {
        return fmt.Errorf("Could not unmarshal: %v", err)
    }

    return nil
}

// PutItem stores your go object in the table
func (b *Backend) PutItem(v interface{}) error {
    item, err := dynamodbattribute.MarshalMap(v)
    if err != nil {
        return err
    }

    _, err = b.Service.PutItem(&dynamodb.PutItemInput{
        Item:      item,
        TableName: b.TableName,
    })
    return err
}

// RetrieveAll returns a pointer to an Iter
func (b *Backend) RetrieveAll() *Iter {
    return NewIter(b)
}