Akka.NET 2017 Roadmap Update

.NET Standard, Akka.Persistence RTM, and More

Fresh off the release of Akka.NET 1.2 last month, we’ve been hard at work moving onto the next set of changes and developments for Akka.NET. So let’s get right into it.

Current State of Akka.NET

First, our previous Akka.NET roadmap from 2016. We accomplished most of what we wanted to achieve on that roadmap, but the exact releases and the dates are all over the place. So just to review what’s happened since this roadmap was written:

  • July 2016. Akka.NET 1.1 - Stable Akka.Cluster; Akka.IO release; Akka.Streams Beta. Helios 2.0 transport and Akka.Remote performance improvements.
  • September 2016. Akka.NET 1.1.2 - Stable Mono support; Downing providers for Akka.Cluster, and lots of other features and fixes.
  • January 2017. Akka.NET 1.1.3 - Akka.DistributedData beta; introduction of Hyperion serializer.
  • April 2017. Akka.NET 1.2 - DotNetty transport with TLS support for Akka.Remote; Akka.Streams RTM; Akka.Cluster.Tools RTM; CoordinatedShutdown; and more.

You can view the full release notes for each of the Akka.NET releases from our Github repository here.

You’ll notice that many of the things we promised in Akka.NET 1.5, such as TLS support did not happen in that order and some proposed changes, such as a new default serializer, have not happened yet.

Without getting too deep into the details, the release of .NET Core in the summer of 2016 had to be factored into our roadmap and we wanted to add support for .NET Standard in 1.5. As we later discovered, adding .NET Standard support that early turned out to be a bit premature: the .NET Standard / .NET Core + tooling rodeo was an unmanageable mess in 2016.

Now that Visual Studio 2017 is out and many of the other libraries we depend on all support .NET Standard / .NET Core, it’s a much easier proposition for...

Akka.NET 1.2: Production-ready Akka.Cluster.Tools and Akka.Streams

TLS support for Akka.Remote, Coordinated Shutdown, Performance Improvements, and More

A ton of work has gone into Akka.NET thus far in 2017, and the biggest release we’ve done since last year’s Akka.NET 1.1 release just hit NuGet: Akka.NET v1.2.

Akka.NET v1.2 is the culmination of months of work on many different fronts at once, and you can read the official Akka.NET 1.2 release notes here. In this post we’re going to explain the significance of the 1.2 release and what it means for the end-users of Akka.NET.

Akka.Streams and Akka.Cluster.Tools Released from Beta

The most notable part of the release is what’s coming out of beta: Akka.Streams and Akka.Cluster.Tools. Both of these modules now have stable APIs and are considered to be sufficiently well-tested and well-used (measured by adoption and usage during its beta period) to be considered full production-ready modules.

Akka.Streams is a subject we intend to cover at length as it’s an amazing, higher-level abstraction built on top of Akka.NET actors that allows end-users to express powerful flows in just a few lines of code. Petabridge has been using Akka.Streams in a number of our consulting projects for months now and both we and our customers are impressed with its conciseness and power.

Akka.Cluster.Tools is built on top of Akka.Cluster and introduces three additional capabilities:

  • Distributed Publish and Subscribe, which we’ve written about recently on the Petabridge blog. In essence this module can be used to create a decentralized message broker that allows Akka.NET actors to subscribe and publish to various user-defined “topics” across the cluster. This can be done transparently without needing to know which subscribers and which publishers are on each node.
  • Cluster Singleton, which is used to help create reliable singleton actors inside a cluster. I.E. you can guarantee that only a single actor of...

Introduction to Distributed Publish-Subscribe in Akka.NET

Decentralized Message Brokers in Akka.Cluster

Today we’ll talk about one of the most common communication patterns, which is publish/subscribe, and how to perform it in a distributed environments using Akka.NET. In case if you want to save yourself some time implementing it, its already available as part of a bigger package called Akka.Cluster.Tools. To install it, you can simply get the latest prerelease version from NuGet:

install-package Akka.Cluster.Tools -pre

Below, we’ll cover the abilities and limitations that come with the Akka.Cluster.Tools.DistributedPubSub implementation.

When EventStream isn’t enough

An idea of distributed publish subscribe came from slightly different design choices than those of the default Akka pub/sub model (EventStream).

EventStream has been invented to work with actor systems from the ground up, even in systems that are not inherently distributed. It’s extremely simple, lightweight, and fast. Dead letters - a place where every undeliverable message lands by default - is implemented on top of it.

However, EventStream comes with some limitations. It works only locally in the scope of the current actor system. This means that you cannot publish/subscribe actors from other nodes and publish messages in a global address space without worrying on which node they live. These limitations were motivation for a separate, cluster-specific publish-subscribe feature.

Event stream publish/subscribe