How to deploy my spray API into production?

问题:

I'm thinking about how should be the process to deploy my already locally tested rest api to the cloud, lets say an infrastructure as a service (not a platform as a service such as Heroku) like amazon.

I have my local envorinment set up with sbt up and running but my question is How should I deploy this in a production environment?

Is it sane to define a process in which the devops pulls the most recent changes from the git repo and then simply executes sbt run?

I want to know how does the teams that uses scala+spray+sbt deploys their apis to a production environment.

回答1:

The heart of our services is scala + akka + spray + mongo. So we are using GitHub for version control. After merging checked PRs to the master branch, Jenkins automaticaly tests'n'builds project. If all tests were successful then Jenking runs a couple of scripts:

1. Increment project version (currently written in shell, but will be changed to sbt)
2. Run assembly task with sbt-assembly
3. Run deploy script (written in Python with Fabric) wich deploys our jar to EC2

Basicaly on the thrid step you have a couple of choices:

Make a runnable jar using IO/Spray boot file:

object Boot extends App {
  implicit val system = ActorSystem("ServiceName")
  val log = system.log
  val service = system.actorOf(Props[Service], name="serviceActor")
  IO(Http) ! Http.Bind(service, interface = host, port = port)
}

Make a runnable jar as Akka's microkernel:

In this case you should extend Bootable trait and override startup and shutdown methods:

class Kernel extends Bootable {
  // many lines of code
  def startup() {
    scheduler.start()
    SomeActorSystem.startup()
  }

  def shutdown() {
    scheduler.shutdown()
    SomeActorSystem.shutdown()
    system.shutdown()
  }
}

Using a TypeSafe startscript:

Can't show an example, but it has a good intro on github =)

We are using all of this way in different cases.

回答2:

You should build a jar with the plugin sbt-assembly

addSbtPlugin("com.eed3si9n" % "sbt-assembly" % "0.9.0")

Then you can run the jar in production with java -jar

If you give version number to your project, this is a rather classic process.

Hope it helps.

回答3:

Never went to PRO with spray-akka. Only pet projects. My suggestions here should be taken as inspiration. I know some of the options I present are costly in terms of maintenance or prone to errors.

Packaging

I only used maven-shade-plugin (no experience with sbt) but I guess there's a similar solution.

Packaging Issues

There's few issues with this approach though. Akka and many of the spray modules use the references.conf and application.conf convention. When assembly/shading all your dependencies the resources (since they are named the same) may overwrite and you'd be unable to start the application.

The quick and dirty solution I found was to copy/paste the application and ref.conf of the dependencies into one controlled by me.