We have been busily re-building our core property listings experience using ReactJS for a while now. After the release of our revamped sold property section, we decided to find a way to engage the other areas of the company and give back to the local tech community.
With that in mind, REA Group is very excited to announce that on the 8th – 10th February 2017 we will be hosting a ReactJS workshop run by the amazing React Training team. React Training is a US based group comprised of ReactJS experts and the creators of some of the most popular open source libraries in the space, many of which we use here.
I have recently been on a Higher Order Component (HOC) craze. HOCs are a good tool for implementing cross-cutting concerns or common functionalities, such as logging and tracking. For more information on HOCs, check out this recent post by my colleague Mehdi Mollaverdi!
Then I discovered Functions as Child Components (FaCC) and a couple of my brain cells perished. FaCC’s are components that receive a function as their child. For example:
So let’s take a trip through struggle town.
After making our journey from Flux to Redux, we were happy with how clean and simple our state management had become so we kept ticking along.
On a Friday a few weeks ago, we deployed a set of minor changes to one of our Rails apps. That evening, our servers started alerting on memory usage (> 95%). Our initial attempts to remedy this situation by reducing the Puma worker count on each EC2 instance didn’t help, and the memory usage remained uncomfortably high through the weekend. On Monday, we popped open NewRelic and had a look in the Ruby VM section. Indeed, both the Ruby heap and memory usage of each web worker process had begun a fairly sharp climb when we deployed on Friday, after being totally flat previously:
However, over the same period of time, the number of objects allocated in each request remained fairly static:
If our requests aren’t creating more objects, but there are more and more objects in memory over time, some of them must be escaping garbage collection somehow. Continue reading
Rabbits, they are small, the are cute, they are fluffy…. and they are terrible fighters*.
Which is why evolution has favoured the skittish amongst them.
The rabbit which was overly cautious and ran away and the first hint of danger survived and went on to produce more rabbits. But the rabbit which was more laid back and waited until it was sure it was in peril before trying to flee did not. Of course running away does have a cost, and if you spend all your time running at the slightest sound you’ll expend a lot of energy and have no time to nibble at the grass and gain more**.
So what do rabbits have to do with Auto Scaling Groups (ASGs)?