Contributing

This pattern repository is curated by the Scala Users Group in Stockholm, Sweden.

Modules

One sbt module should have examples of a common theme.

Start off by creating a copy of the module-template module and add it to build.sbt.

Add the dependencies you need in the module’s build.sbt. Standard dependencies are declared in project/Dependencies.scala. Declare additional stuff directly in libraryDependencies.

Endpoints

To enable working examples we’ve put a few ready-to-use endpoints in the playground module. Its dependencies are declared optional, so whenever you use parts of it, you’ll need to add the required dependencies.

JMS

You may start an embedded ActiveMQ JMS broker.

Scala

  ActiveMqBroker.start()

HTTP

If you’d like to send data via HTTP, start an embedded Akka Http server as below.

Scala

  WebServer.start()

It exposes

• GET localhost:8080/hello – replies with a constant JSON snippet
• Web socket localhost:8080/webSocket/ping – the web socket echos the message a bit wrapped

Kafka

If you’d like to use Kafka in the examples, add embeddedKafka as libraryDependency and start Kafka as documented on the Embedded Kafka site.

Documentation

This site is generated by Lightbend’s Paradox Markdown Engine.

It supports embedding snippets from other files with this notation, where #textmarker must be present in the denoted file.

Markdown

@@@snip(..relative/path/to/file) { #textmarker }

See Paradox’ Sinppet inclusion for details.

As the project applies automatic code formatting with Scalafmt, you may want to switch it off for snippets used as documentation.

Scala

// format: off
// # snippet-marker
val httpConnectionFlow: Flow[HttpRequest, HttpResponse, Future[Http.OutgoingConnection]] =
  Http().outgoingConnection("localhost", 8080)
// # snipper-marker
// format: on

Run sbt docs/preiewSite to generate and open reference docs while developing.