Entity-Component-System (ECS) is a distributed and compositional architectural design pattern that is mostly used in game development. It enables flexible decoupling of domain-specific behaviour, which overcomes many of the drawbacks of traditional object-oriented inheritance.
Elixir is a dynamic, functional language built on top of the Erlang VM designed for building scalable and maintainable applications.
In this article, discover how we can use both ECS and Elixir in a novel approach to structure our programs beyond the class based inheritance paradigm.
Publish-Subscribe is a messaging pattern that works as follows: a group of consumers subscribe to events of a given topic and are notified whenever an event of that topic arrives.
When an event is published into a topic channel, the channel delivers a copy of the message to each of the output channels. The advantage of this is we can decouple the consumers from the producers. Neither party need knowledge of each other to communicate.
In other words, pub-sub is a pattern used to communicate messages between different system components without the components knowing anything about each other’s identity.
Let’s look at an implementation of Publish-Subscribe in Elixir. The full source code is provided below.
A hash tree or Merkle tree is a tree in which every non-leaf node is labelled with the hash of the labels or values (in case of leaves) of its child nodes. Hash trees are useful because they allow efficient and secure verification of the contents of large data structures.
Hash trees are used in the IPFS file system, BitTorrent protocol, Git, Bitcoin, Ethereum, and a number of NoSQL systems like Apache Cassandra and Riak.
They are used for many kinds of verification, especially of large chunks of data.
You develop an API backend with a few endpoints and deploy it to production. You publish several official language-specific API clients as well as an API documentation. Your API announces its public release; other developers start using it. Your day ends on a happy note.
The following day, you want to add a new feature to your API. You notice that you have to do a few things:
Update the server implementation to support the new feature.
Update the client libraries (one for each supported platform and language.)