simple in-memory store with consistent reads

Problem Statement

Suppose you want to write a simple in-memory JSON store with an equally simple socket based protocol. You want this in-memory store to support parallel and consistent reads. By “parallel reads” what I mean is if 10 clients request to read data from the store then no client should be blocking any other client. By “consistent reads” what I mean is when a client requests some data from the store there is absolutely no way that client gets half of the data before a write and half of it after a write and there is also some kind of ordering for reads and writes. In other words, if we have an array “[1,2,3,4]” that corresponds to the key “ints” in our JSON store then the following sequence of events is impossible: Continue reading

enforcing invariants with singleton classes and method redefinitions

If you play around with Ruby long enough you start to notice that Ruby programmers overall tend to prefer small domain specific libraries, Ruby on Rails notwithstanding. There are many good reasons for this kind of approach from a software engineering perspective but the biggest reason is that Ruby makes it extremely easy by providing the right kind of metaprogramming facilities. Continue reading