All posts in process registry

A journey to Syn v2, a better Erlang & Elixir Process Registry and Group manager

By Roberto Ostinelli / November 18, 2019 / 3 Comments

For those who don’t know it, Syn (short for synonym) is a global Process Registry and Process Group manager for Erlang and Elixir that I’ve written a few years back. It has been around for some time now, and it has served me well on many occasions. Through the years, I’ve built up a series of considerations and ideas for improvement, and now the time has come to put all of these back into Syn.

Syn v2 has been rewritten from the grounds up, and I’d like to share the reasoning and the architectural choices behind this work. Since Syn is written in Erlang, the few portions of the code here below will show Erlang syntax. Don’t let that discourage you if you are an Elixir developer though, as the same principles apply.

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An evaluation of Erlang global process registries: meet Syn

By Roberto Ostinelli / July 6, 2015 / 12 Comments

Due to my personal interests and history, I often find myself building applications in field of the Internet Of Things. Most of the times I end up using Erlang: it is based on the Actor’s Model and is an ideological (and practical) perfect match to manage IoT interactions.

I recently built an application where devices can connect to, and interact with each other. Every device is identified via a unique ID (its serial number) and based on this ID the devices can send and receive messages. Nothing new here: it’s a standard messaging platform, which supports a custom protocol.

Due to the large amount of devices that I needed to support, this application runs on a cluster of Erlang nodes. Once a device connects to one of those nodes, the related TCP socket events are handled by a process running on that node. To send a message to a specific device, you send a message to the process that handles the devices’s TCP socket.

While building this application, I was early in the process faced with a very common problem: I needed a global process registry that would allow me to globally register a process based on its serial number, so that messages can be sent from anywhere in the cluster. This registry would need to have the following main characteristics:

  • Distributed.
  • Fast write speeds (>10,000 / sec).
  • Handle naming conflict resolution.
  • Allow for adding/removal of nodes.

Therefore I started to search for possible solutions (which included posting to the Erlang Questions mailing list), and these came out as my options:

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