A free, once-weekly Scala news flash. Easy to unsubscribe. Goes out every Thursday.
February 20th, 2020, ISSUE 314

READING

Using Dotty Union types with Akka Typed

Based on what I’ve read and experimented with, it’s obvious that Dotty brings a lot of features that enable writing more concise and clearer code.
Eric Loots (@lootser)
About Variance

Variance is a complicated topic but it does not need to be. Its main purpose is to provide us with typesafe substitution but also with improved type inference.
Francis Toth (@francistoth)
My FP Journey

A story of a journey through paradigms and libraries.
Zach Albia
Creating a dead simple CountDownLatch with ZIO

We created a simple and non-blocking CountDownLatch with very little code, which is valuable for making our test suite more robust.
Amitay Horwitz (@amitayh)
ZIO STM: CountDownLatch in two lines

Here's a follow-up to the previous post, with an alternative approach.
Ferdinand Svehla (@fsvehla)
2019 Scala Developer Survey

The Scala Center, the LAMP, and Lightbend would like to know more about your habits as a Scala programmers and to identify the pain points of your workflow.
Scala Center (@scala_lang)
Benchmarking Web Services using GraalVM Native Image

In a previous post I discussed the steps needed to compile a http4s web service to an executable with GraalVM Native Image. It’s natural to ask what tradeoffs are made by going this route instead of using the JVM. In this post I present several benchmark results I obtained comparing the Native Image executable to the running on the JVM.
Noel Welsh (@noelwelsh)
Operating Akka Clusters using KUDO

The combination of extensible, open, dynamically scalable infrastructure (Kubernetes plus KUDO), with an extensible, open stateful runtime (Akka) opens up amazing possibilities.
Michael Beisiegel (@realmbgl)
Testing with Functional Programming in Scala

How you can apply functional programming concepts to gain confidence about your API code with minimum effort.
Leonti Bielski
Deploying a full stack Scala application on Heroku

Share a lot of code between your frontend and your backend, avoiding a lot of hassle in writing twice model definitions and validations.
Antoine Doeraene (@doe_antoine)
Elasticsearch Geo-point queries with Scala

Using Elasticsearch geo_point queries with Scala application.
λ.eranga (@itseranga)

PRESENTATIONS

Data Juggling - Part 5 - Curry-Howard-Lambek Correspondence

This video is an overview of the famous isomorphism between mathematical proofs, computer programs and category theory.
DevInsideYou (@DevInsideYou)

EVENTS

Stairway to Scala Workshop, March 16-20, 2020, San Damiano, CA, USA

Use code: SCALATIMESMAR20 to get -10%.
Artima, Inc (@ArtimaInc)
Scalar, March 19th-21st 2020, Warsaw, Poland

Get ready for the workshop-driven FP event in Poland!
SoftwareMill (@scalarconf)
ZIO Hackathon, March 22nd-23rd 2020, Warsaw, Poland

Over the course of two days, we will share and learn about ZIO and related projects; chat about functional programming, functional Scala, and much more; work on fun projects; and get to know one another.
Ziverge (@zivergetech)
ScalaUA, April 3th-4th 2020, Kyiv, Ukraine

Wholesale 10+ tickets are available till 2020.04.02.
ScalaUA (@ScalaUA_Conf)
flatMap(Oslo), May 14th-15th 2020, Oslo, Norway

The call for papers are open til until 1st of March. Also, user our link for a special discount for Scala Times readers!
flatMap(Oslo) (@flatmaposlo)
Scala Swarm 2020, June 18th-23rd 2020, Porto, Portugal

Ticket sale is now open, come quick and grab your ticket to this unique event!
ScalaSwarm (@ScalaSwarmConf)

RELEASES

zio-grpc

ScalaPB meets ZIO: write purely functional gRPC services and clients using ZIO.
zio-grpc contributors
typelevel-library.g8

Template for starting FP libraries ready to be published.
Alex Nedelcu (@alexelcu)

VARIA

Scala Times banners?

Want one? Click here
THE INTERNET
Scala Times stickers?

Want one? Let us know or tweet @scalatimes.
THE INTERNET
Scala experts?

Need some? SoftwareMill is here, ready to talk and dive deep into your code.
SoftwareMill





  1. Scala Times Issue #327

    Time traveling in tests with Cats Effect. Lightbend To Contribute Commercial Features To Akka Open Source. Functional error handling with monads, monad transformers and Cats MTL. Akka Stream Coexistence With Akka Typed. Orchestrating startup and shutdown in Scala.


  2. Scala Times Issue #326

    A story about streaming unique batches in Monix. GraalVM Native Image Tips & Tricks. Mu-Scala 0.22: Distributed tracing. Using a remote server to build your Scala projects. Circe - Part 2 - JSON Codecs.


  3. Scala Times Issue #325

    Scala Start Page. Starting with Scala 3 macros: a short tutorial. Implementing Authentication on Play Framework. Lunatech and our commitment to the Scala Center. Scala Native Next Steps.


  4. Scala Times Issue #324

    A simple trick to improve type safety of your Scala code. The Power of Akka Streams. Akka Persistence JDBC 4.0.0 release candidate. Scala Book: Free PDF, Mobi, and ePub versions. Testing Embedded H2 DB with Scala and Scalatest.


  5. Scala Times Issue #323

    ZIO + Http4s: a simple API client. FP for Mortals for Cats!. An Introduction to ZIO Kafka. Akka Typed Fundamentals (PL), Online Workshop, April 27th. Scalar Online, May 15th (Extended CFP).


  6. Scala Times Issue #322

    The Death of Hype: What's Next for Scala. IntelliJ Scala Plugin 2020.1. Data processing with Akka Actors: Part II. Akka-http graceful shutdown. A Brief History of ZIO.


  7. Scala Times Issue #321

    Tapir codecs get an update. Data processing with Akka Actors: Part I. A functional comparer. Data Juggling - Part 11 - Getting Started with Squants. Scalar Online, May 15th (CFP).


  8. Scala Times Issue #320

    New feature: Search!. Bake your bread tagless-final style. User-land compiler warnings in Scala. Zio ZLayer with playframework. Testing background process with ZIO.


  9. Scala Times Issue #319

    From idea to product with ZLayer. Edge to Cloud: Building the Tesla Virtual Power Plant . What's the Point of Applicative?. Using ScalaCheck with MUnit. Monitoring and tracing for Akka applications under kubernetes (k8s).


  10. Scala Times Issue #318

    Akka Cluster application design. Spring to ZIO 101. NE Scala in the Time of Social Distancing. Scala 3 support in IntelliJ Scala plugin. Separate Docker Layers for Dependencies and App JARs.


  11. Scala Times Issue #317

    Using Google Datastore with akka-persistence. Functional Program (Re)Design. Writing native CLI applications in Scala with GraalVM. Data Juggling - Part 8 - Getting Started with refined. Fundamentals of Scala, March 14th-15th, Lagos, Nigeria.


  12. Scala Times Issue #316

    How to publish a Scala library in GitHub. Announcing Cats STM 0.7.0. Baking Peixinhos da Horta with ING’s Baker Library. Fundamentals of Scala, March 14th-15th, Lagos, Nigeria. Stairway to Scala Workshop, March 16th-20th, San Damiano, CA, USA.


  13. Scala Times Issue #315

    ZIO for IntelliJ. Scala 2 community build reaches goals. Cats Effect Ref. Using Dotty Union types with Akka Typed – Part II. Caliban Client: a type-safe GraphQL Client for Scala and Scala.js.


  14. Scala Times Issue #314

    Using Dotty Union types with Akka Typed. My FP Journey. Creating a dead simple CountDownLatch with ZIO. ZIO STM: CountDownLatch in two lines. 2019 Scala Developer Survey.


  15. Scala Times Issue #313

    Building Serverless Scala Services with GraalVM. Alpakka Kafka 2.0 Released | @lightbend. Haskell for impatient Scala developer: Getting into speed. Building useful Scalacheck Generators. Easily create New Sync Types with ZIO STM.


  16. Scala Times Issue #312

    Happy eyeballs algorithm using ZIO. How (not) to use shapeless for cross-layer conversions in Scala. So you want to compose some functions. RESTful error handling with Akka HTTP and the library “endpoints”. MUnit is a new Scala testing library · MUnit.


  17. Scala Times Issue #311

    Introducing error reporting in optics. GraphQL in Scala with Caliban - Part 1. Tidying up your SBT file with Scala. Dependency injection with Reader Monad in Scala. Etcd watch API integration with scala and cats-effect.


  18. Scala Times Top Links of 2019

    January: Scala Best Practices. February: Is your Scala object always a singleton?. April: Did Functional Programming get it wrong?. May: The little gems of Scala standard library. June: The Evolution of a Scala Programmer.


  19. Scala Times Issue #310

    Git hooks in Scala projects  - the easy way!. Testing Doobie programs. Implementing typeclasses in Scala I. Effective testing with ZIO Test. Akka Streams: error handling in event processing pipelines.


  20. Scala Times Issue #309

    Towards more functional Play — Part 2. TMWL’ Dec 19 — Scala 3 overview, Scala hacks and DevOps hints. Scala etcd client with etcd4s and cats-effects. Boilerplate-free type class definition. GCP Cloud Functions with Scala.js in 10 lines(ish).


  21. Scala Times Issue #308

    Towards more functional Play  -  Part 1. ZIO environment meets constructor-based dependency injection. How-to run tests in parallel with sbt. Learn myself some Scala 3, episode 4: strict equality. 5 pitfalls to avoid when starting to work with ZIO.


  22. Scala Times Issue #307

    Standardizing IO Interfaces for Scala Libraries. WebSocket Streaming with Scala. State of Monocle. Scala tooling in 2019. How to Work with Scala Collections in Java.


  23. Scala Times Issue #306

    2019 Scala Developer Survey . Lessons Learned Building a Van Laarhoven Lens Library. A Glossary of Functional Programming. Tips for moving from tut to mdoc. Notes on Category Theory in Scala 3 (Dotty).


  24. Scala Times Issue #305

    Beyond Liskov: Type Safe Equality in Scala. Scala 2 Roadmap Update: the Road to Scala 3. Explicit nulls are in!. Functional Scala London 2019: Day 1. Leveraging Monoids for More Powerful Summarization.


  25. Scala Times Issue #304

    Akka references serialization with Protobufs (up to Akka 2.5). TMWL November’19 — ScalaTest, Medusa, PW-Sat2 cubesat. Implement your future with ZIO. Decouple the Program from its Implementation with ZIO modules. ZIO environment and modules pattern: zio, scala.js, react, query management.


Organizing an event?
Promote it with
Scala Times.
The Scala Times reader?
Get a banner!
Got a tip?Send it in!
Follow us onTwitter.
Curated bySoftwareMill.
We arehiring.
Andtaking on projects.