For the love of all that is dear to software development avoid parallel but separate class hierarchies. Today we’re going to talk a little bit about type hierarchy design and why composition is useful to consider in certain scenarios. ...
Performance counters can be implemented in applications to help operators determine where bottlenecks are in the design. Microsoft has a decent page, that’s somewhat Windows centric, about performance counters. This post is about implementing the most basic type of counter, a value which monotonically increases, in JavaScript for NodeJS and the performance implications of different designs. ...
Note I didn’t say always should export objects, but for the sanity of everyone involved, in many cases a required module should return a constructor and not a fully instantiated object. Today’s post is about why your NodeJS modules should look like this: /** * @constructor */ function myConstructor(someDependency) { /* setup my object here */ } module.exports = myConstructor; and not this: var myObj = { myService: new MyService() }; myObj.myFunction = function(foo) { /* do stuff with foo here */ }; module.exports = myObj; ...
Operational monitoring of a software application is one of the activities the ensures a successful public launch. Too often it seems like a service’s course to public availability looks something like, Conceptualization → Development → … → SHIP IT. The “…” component is an important step at large enterprises with large public services (like Expedia, Amazon.com, etc) and involves developing a way to monitor an application whilst running it. At smaller organizations though I have seen this smaller step get discarded or not looked at. Today’s post offers a few thoughts on what logging and monitoring looks like today. ...
Recently I began work on a project to manage the deployment of a product built using a microservices architecture. As a result of our chosen architecture we have a large number of services which will communicate to each other over HTTP/S. Instead of using fixed IPs we decided to used DNS SRV records to indicate where services could contact their dependencies. Today’s post goes into using SRV records in a little more detail and the problem they solve. ...
I’ve written before about how it’s better to write straightforward code than trying to be clever and pre-optimize. Another example of where this rule is true is the cost of iteration between different styles of array loops in JavaScript when executed within NodeJS. ...
Martin Folwer’s blog and website is a common reference for modern design pattern so we will start with his glossary definition for the repository pattern. The linked article contains more detail, but in short a ‘repository’ acts as an data store layer on top of the storage system and provides (more) object oriented methods for accessing said system. Unfortunately, something I have also seen is the over application of this pattern in combination with RDBMS ORMs leading to contorted code with unnecessary interfaces and classes. This post covers what I have seen in some projects in order to provide some of the code smells to avoid. ...