A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
January 9th, 2019, ISSUE 256


Where is the llama for FS2?

During this post we are going to take a look at the different system integration tools and libraries, verify if there is the Alpakka equivalent for FS2 (let’s call it for now Llama), and see what are the other options for FS2.
Michał Matłoka (@mmatloka)
Scala Best Practices - Foreword

A collection of useful hints.
Nicolas Rinaudo (@NicolasRinaudo)
Aecor - Purely functional event sourcing in Scala. Part 4b

1 month, 6 posts and we have finally covered bread and butter of eventsourcing with Aecor.
Vladimir Pavkin (@vlpavkin)
Postgresql from Spark, how to query?

A short example to help you handle such cases.
Leo Benkel (@LeoBenkel)
typebus: A modern guide for building distributed systems with scala and akka

Typebus is my mildly opinionated toolkit for building reactive microservices, abstracting away a publish/subscribe bus implementation.
Corey Auger (@coreyauger)
Error Handling in Akka Actor (with Future)

Handling errors can be tricky!
Linda Hong
An Introduction to ScalaTion Part 2  - HelloWorld of Data Science

In Part 2, we execute our first ScalaTion script — HelloWorldOfDS.scala .
Christian McDaniel
Writing a Spark Dataframe to an Elasticsearch Index

Elastic provides Apache Spark Support via elasticsearch-hadoop, which has native integration between Elasticsearch and Apache Spark.
Oliver Mascarenhas (@olly0808)
Session Windows in Akka Streams

In this post, I implemented a session based window as a custom operator in Akka Streams.
Efe Kahraman (@efeuska)
Rison: URI friendly strucured data representation

Rison is a data format which is similar to JSON but extremely URI friendly.
Naoki Takezoe (@takezoen)
Load Testing using Gatling.io 3.0 for Beginners

The reasons why I choose Gatling.IO 3.0 are: Load tests are written in Scala, it has multi-core support, and it has a free and an enterprise version.
Marko Stapfner
Setting up a Spark machine learning project with Scala, sbt and MLlib

A quick example how to do the setup.
Pedro Costa


Homegrown Scala Collections - Part 20 - Trampolines for CPS

In this video we will learn about trampolines - a tail call elimination technique used in CPS programs. This is part 1/2.
DevInsideYou (@DevInsideYou)


Scalar, Warsaw, Poland April 5-6, 2019

Join the next edition of the largest Scala conference in central Europe!
SoftwareMill (@softwaremill)
Lambda Days, Kraków, Poland, February 21-22, 2019

Use promo code SCALArlz10 for a 10% discount for our readers!
LambdaDays (@LambdaDays)



Patterns from category theory and abstract algebra in Scala.
Piotr Paradziński


Scala Times banners?

Want one? Click here
Scala Times stickers?

Want one? Let us know or tweet @scalatimes.

  1. Scala Times Issue #274

    AST playground: recursion schemes and recursive data. Rethinking Streaming Workloads with Akka Streams: Part I. Sharing is Caring!. A Scala tutorial for Java developers. Scala: Useful User Information + Why you should consider the Language.

  2. Scala Times Issue #273

    Community and Communication. Futures Made Easy with Scala. Scala: Useful User Information + Why you should consider the Language. Using 47 Degree's Fetch library with ZIO. Scala Compilation Got 5x Faster With Triplequote Hydra.

  3. Scala Times Issue #272

    The little gems of Scala standard library. Practical fiber safety (and how Concurrent implies Parallel). Typelevel Sustainability Program Announcement. Homegrown #Scala Collections - ScalaCheck / ScalaTest Integration. Alphabet Soup: Lensing, for free.

  4. Scala Times Issue #271

    ZIO & Cats Effect: A Match Made in Heaven. Concurrency is complicated. An introduction to Law Testing in Scala. Celebrating 10 Years of Akka. Alphabet Soup: Type-level transformations.

  5. Scala Times Issue #270

    Akka 2.6 roadmap. Extending MapR Database Queries Using Scala Polymorphic Types. Marvels of functional programming: Composing effects with monads. Traverse your HLists for fun and profit. Did Functional Programming get it wrong?.

  6. Scala Times Issue #269

    Scalar 2019 whiteboard voting. 38 lines of code towards better data validation in Scala. Scala: Internals and Intermediates. Hacker News API Part 5. Scala Ordering Crash Course.

  7. Scala Times Issue #268

    Functional Hangman with ZIO. Scala or Go: Tastes Great or Less Filling?. An Example of Free Monads and Optimization. Homegrown Scala Collections - Part 29 - Are Views Typeclasses?. Scalar, Warsaw, Poland April 5th - 6th.

  8. Scala Times Issue #267

    Bloop’s compiler performance is ~29% faster than SBT. Fourth batch of Scala 3 SIPs. Functional Hangman with ZIO. Scala: Understanding Variance. Fun with mutually-recursive typeclass resolution.

  9. Scala Times Issue #266

    The RedMonk Programming Language Rankings: January 2019. A monad is not a burrito. Joins in Apache Spark - Part 3. Scala sbt Project Directory Structure. Scala Snippets #1: Instantiable Implicits.

  10. Scala Times Issue #265

    Testing Incrementally with ZIO Environment. Finally Tagless - Not Quite Dead Yet. Functional Testing with Tagless-Final. Monad Transformers aren’t hard!. The Functional Scala Concurrency Challenge.

  11. Scala Times Issue #264

    Final Tagless seen alive. Effectful Episode with John de Goes. State vs Stateful Actor. Phil Bagwell Nominations. Introduction to Akka Streams.

  12. Scala Times Issue #263

    Describe, then interpret: HTTP endpoints using tapir. Vue.js with Playframework. Mu-RPC: defining messages and services. Validate Service Configuration in Scala. Modern Systems Programming And Scala Native With Richard Whaling.

  13. Scala Times Issue #262

    Is your Scala object always a singleton?. Freer doesn’t come for free. Maintaining Binary Compatibility in Scala. Anatomy of functors and category theory. A little Scala 'sed' class.

  14. Scala Times Issue #261: from Scala with love

    Aecor — Purely functional event sourcing in Scala. Part 5. Homegrown #Scala Collections - Foldable Maps. Kubernetes Liveness and Readiness Probes Revisited. Streams and Resource Safety | Akka. Assemble messages from Akka Actors.

  15. Scala Times Issue #260

    Cats Ecosystem Community Survey 2018 Results. Thread Pool Best Practices with ZIO. Purely functional parallelism in Scala. Finatra meets Ammonite. Typed Supervision: why the changes?.

  16. Scala Times Issue #259

    State of Scala compilation time in 2018. Low-memory symbol indexing with bloom filters. Finally: Top-level Definitions. Why you should think about functional programming. Toward a polyglot James server….

  17. Scala Times Issue #258

    Scala Days 2019 - Celebrating Collaborative Success. Scala community build grows, adds Scala 2.13 and JDK 11. Type-checked triple equals: Scala test. Using Scala Plugins From Gradle. Exploring Explicit Nulls in Dotty.

  18. Scala Times Issue #257

    High-Performance Functional Programming Through Effect Rotation. Trampolines for Everything. This month at SoftwareMill we’ve learned — December’18. A Guide to Scala Collections: Exploring Monads in Scala Collections. Spark Custom Stream Sources.

  19. Scala Times Issue #256

    Where is the llama for FS2?. Scala Best Practices - Foreword. Aecor - Purely functional event sourcing in Scala. Part 4b. Postgresql from Spark, how to query?. Error Handling in Akka Actor (with Future).

  20. Scala Times Issue #255

    ADT through the looking glass - lenses, prims and other optics. Hpc with scala and akka Actors. Scala Type Classes - The Name Printer. Evolutionary Algorithms on the JVM via Scala  -  a minimal introduction. Aecor - Purely functional event sourcing in Scala. Part 4a.

  21. Scala Times Issue #254

    Cats Ecosystem Community Survey 2018. Scala Developer Suvey Results 2018. Minutes of the 11th meeting of the Scala Center, Q4 2018. Software as a Reflection of Values With Bryan Cantrill. Dotty: An Alternative to Implicits.

  22. Scala Times Issue #253

    Scala Variables - Syntax, Declaration, Use case, Examples - Leo Benkel. Fast goto definition with low memory footprint · Metals. New Akka Getting Started Guide. Different ways to understand a monad. MOOC: Introduction to programming with dependent types in Scala.

  23. Scala Times Issue #252

    The F-words: functor and friends. Grafter  -  a take on yet another DI library. Anatomy of a Scala quirk. Creating Work Queues with Apache Kafka and Apache Pulsar. Terminus - Cross Platform Terminal Emulator for Sublime Text.

  24. Scala Times Issue #251

    Scala Numerical Performance with Scala Native and Graal. SBT Plugin - How to make it, debug it, improve it?. Better than IO, part 1. Scala and Slick - An Introduction. Category Theory for Programmers: Scala Edition 1.1-RC.

  25. Scala Times Issue #250

    Correlation IDs in Scala using Monix. Further enhance `new` syntax to reduce boilerplate. Counting type inhabitants. Variances in Scala. SIP Meeting Minutes - November 1-3 2018.

Organizing an event?
Promote it with
Scala Times.
The Scala Times reader?
Get a banner!
Got a tip? Send it in!
Follow us on Twitter.
Curated by SoftwareMill.
We are hiring.
And taking on projects.