Book Image

Scala Programming Projects

By : Mikael Valot, Nicolas Jorand
Book Image

Scala Programming Projects

By: Mikael Valot, Nicolas Jorand

Overview of this book

Scala Programming Projects is a comprehensive project-based introduction for those who are new to Scala. Complete with step-by-step instructions and easy-to-follow tutorials that demonstrate best practices when building applications, this Scala book will have you building real-world projects in no time. Starting with the fundamentals of software development, you’ll begin with simple projects, such as developing a financial independence calculator, and then advance to more complex projects, such as a building a shopping application and a Bitcoin transaction analyzer. You’ll explore a variety of Scala features, including its OOP and FP capabilities, and learn how to write concise, reactive, and concurrent applications in a type-safe manner. You’ll also understand how to use libraries such as Akka and Play. Furthermore, you’ll be able to integrate your Scala apps with Kafka, Spark, and Zeppelin, along with deploying applications on a cloud platform. By the end of the book, you’ll have a firm foundation in Java programming that’ll enable you to solve a variety of real-world problems, and you’ll have built impressive projects to add to your professional portfolio.
Table of Contents (18 chapters)
Title Page
Copyright and Credits
Packt Upsell
Contributors
Preface
Index

Heroku configuration


How does Heroku know how to execute the application?

Heroku knows how to execute the application by reading the instructions from a file named Procfile, located at the root of the project; the content is as follows:

web: server/target/universal/stage/bin/server -Dhttp.port=$PORT -Dconfig.file=server/conf/heroku.conf

The first indication in the line is the type of application. This can be anything. The web value is a special type, telling Heroku that this process only receives requests from HTTP.

The second part is the path to the executable. In fact, the SBT project creates this executable for us during the build process.

The last part is a list of properties for the Play application, namely

  • -Dhttp.port, which sets the port to listen to by using the Heroku variable, $PORT
  • -Dconfig.file, which set the configuration file path to be used by the application.