lulo/async-dynamo

Asynchronous Scala client for Amazon DynamoDB

async-dynamo

This fork was created to work with AWS 1.5, AKKA 2.1, and Play 2.1.

With this fork you can publish to your local maven repo so it can easily be included in your own projects without waiting on others to setup new releases.

KNOWN ISSUES

Despite the examples you CANNOT convert case classes directly to the AWS msg unless the case class has all Strings as arguments. This means code like

    case class Person(id :String, name: String, email: String)
    implicit val personDO = DynamoObject.of3(Person) // make Person dynamo-enabled

    if (! TableExists[Person]()) //implicit kicks in to execute operation as blocking
      CreateTable[Person](5,5).blockingExecute(dynamo, 1 minute) // overriding implicit timeout

    val julian = Person("123", "Julian", "[email protected]")
    val saved : Option[Person] = Save(julian) andThen Read[Person](julian.id) // implicit automatically executes and blocks for convenience
    assert(saved == Some(julian))

may work, but code like this does not due to the Long id value:

    case class Person(id :Long, name: String, email: String)
    implicit val personDO = DynamoObject.of3(Person) // make Person dynamo-enabled

    if (! TableExists[Person]()) //implicit kicks in to execute operation as blocking
      CreateTable[Person](5,5).blockingExecute(dynamo, 1 minute) // overriding implicit timeout

    val julian = Person("123", "Julian", "[email protected]")
    val saved : Option[Person] = Save(julian) andThen Read[Person](julian.id) // implicit automatically executes and blocks for convenience
    assert(saved == Some(julian))

This means you have to write custom converters for each of your objects unless all your objects have only strings and less than 8 arguments. That being said, unless you plan on taking advantage of their async layer on top of the normal calls, it is not worth using this library IMO.

If these things are not show stoppers for you, feel free to use the code. I am no longer going to fix/update/maintain any code within this library.

Overview

async-dynamo is an asynchronous scala client for Amazon Dynamo database. It is based on Akka library and provides asynchronous API.

Quick Start

For detailed information please read User Guide.

SBT

First checkout this fork, make any changes you want/need, then run sbt publish to generate the jar in your local repo

In any project you want to utilize the jar in, just add this to your built.sbt file:

resolvers += "Local Maven Repository" at "file://" + Path.userHome.absolutePath + "/.m2/repository"

libraryDependencies += "asyncdynamo" %% "async-dynamo" % "1.7.3"

Example

import asyncdynamo._
import nonblocking._
import scala.concurrent.duration._
import akka.util.Timeout

object QuckStart extends App{
  implicit val dynamo = Dynamo( DynamoConfig( System.getProperty("amazon.accessKey"), System.getProperty("amazon.secret"), tablePrefix = "devng_", endpointUrl = System.getProperty("dynamo.url", "https://dynamodb.eu-west-1.amazonaws.com") ), connectionCount = 3)
  implicit val timeout = Timeout(10 seconds)

  try{
    case class Person(id :String, name: String, email: String)
    implicit val personDO = DynamoObject.of3(Person) // make Person dynamo-enabled

    if (! TableExists[Person]()) //implicit kicks in to execute operation as blocking
      CreateTable[Person](5,5).blockingExecute(dynamo, 1 minute) // overriding implicit timeout

    val julian = Person("123", "Julian", "[email protected]")
    val saved : Option[Person] = Save(julian) andThen Read[Person](julian.id) // implicit automatically executes and blocks for convenience
    assert(saved == Some(julian))

  } finally dynamo ! 'stop
}

Asynchronous version

val operation = for {
  _ <- Save(julian)
  saved <- Read[Person]("123")
  _ <- DeleteById[Person]("123")
} yield saved

(operation executeOn dynamo)
  .onSuccess { case person => println("Saved [%s]" format person)}
  .onComplete{ case _ => dynamo ! 'stop }

Explicit type class definition

If you need more flexibility when mapping your object to Dynamo table you can define the type class yourself, i.e.

    case class Account(id: String, balance: Double, lastModified: Date)

    implicit val AccoundDO : DynamoObject[Account] = new DynamoObject[Account]{
        val table = "account"
        def toDynamo( a : Account)  = Map( "id" -> a.id,
                  "balance" -> a.balance.toString,
                  "lastModified" -> formatter.toString(a.lastModified )

        def fromDynamo(f: Map[String, AttributeValue]) =
            Account( f("id").getS, f("balance").getS.toDouble, formatter.parse(f("lastModified").getS) )
    }

Information for developers

Documentation

For detailed information please read User Guide.

AWS Credentials

In order for tests to be able to connect to Dynamo you have to open Amazon AWS account and pass the AWS credentials to scala via properties. The easiest way to do this is to add them to SBT_OPTS variable, i.e.

export SBT_OPTS="$SBT_OPTS -Damazon.accessKey=... -Damazon.secret=..."

To build async-dynamo run:

 sbt clean test

Copyright and license

Copyright 2012 2ndlanguage Limited. This product includes software developed at 2ndlanguage Limited.

Licensed under the [Apache License, Version 2.0] license (the "License"); you may not use this software except in compliance with the License.

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.