Monthly Archives: December 2015

Elixir on CircleCI – Updated

I once configured elixir build at CircleCI (Elixir on CircleCI), but haven’t been able to update it. As some of the builds are failing, I’ve updated the configurations as follows.

CircleCI doesn’t seem supports erlang/elixir builds, but there’s nice library (asdf) to configure specified versions of them. The 1st time build takes time, but caching works well and 2nd time or later becomes fast enough.

Watching/Reading – Reactive Design Patterns – Cont.

Continuing to read the book and additional notes are,

  • Asynchronous interfaces helps decoupling modules and provides horizontal scalability.
  • Location transparency – By writing the application in a distributed manner, even for the local processing, your application can become resilient to the failure. It makes writing tests easier too.
  • Akka’s Actor systems ( provides simple interface for message passing between components. It provides simple interface and it makes it easier to tests through stubs/mocks on the interface.
  • You need to work with non-determinism in distributed systems. One approach is explicitly synchronize for avoiding ordering issue. The other is to avoid/isolate computations which will be affected by the computation order.
  • Back-pressure and flow control becomes required between components. Reactive stream ( is one way to control flow.
  • Netflix is building Chaos Monkey which randomly disabled production instances for ensuring system resiliency (

This book covers various concepts and methodologies for building solid system in a distributed manner. Also, the examples written with Scala is relatively simple and good to understand.

Also, the following coursera courses covers similar topic and would help gaining knowledge on this topic too.