Recently I’ve been repeatedly asked how to get started with programming, especially Ruby and Rails. To keep things DRY and make sure I always include all great resources for learning, I decided to write this blog post. Most of people who asked me had never programmed before or had done some coding before in other languages, but are not (yet) proficient developers, so if you are a total beginner or just started learning Ruby / Rails and you are not sure what the next step is then you came to the right place.
In many Rails applications the modeling is limited only to creating classes inheritng from
ActiveRecord::Base which are 1:1 mapped to database tables. Having AR models like
Project doesn’t tell much about the domain of your application. Well, you can add some domain logic to the models but that way you will easily end up having giant classes with thousands lines of code, so let’s just use models for database-related stuff only. Other option would be to create service objects for every usecase. That’s a good and clean way, but it’s merely the interaction layer between different parts of your application. You may end up easily with all logic encapsulated within service objects that will start looking more like procedural programming rather than proper OOP and not real domain API at all. The good news is that you can easily counteract it: time to use composed models.
There’ve been a lot of discussions for several months about “The Rails Way” and problems associated with it - huge models with several thousands lines of code and no distinguishable responsibilities (User class which does everything related to users doesn’t tell much what the app does), unmaintainable callback hell and no domain objects at all. Fortunately, service objects (or usecases) and other forms of extracting logic from models have become quite mainstream recently. However, it’s not always clear how to use them all together without creating huge classes with tens of private methods and too many responsibilities. Here are some strategies you can use to solve these problems.
You’ve started developing new app and need server to deploy it. You can choose hosting platform like Heroku or Shelly which may turn out to be quite expensive if you want to host multiple apps. You can also set up your own server. Going with the latter option can be quite time consuming, especially if sysadministration is not you main responsibility and you have multiple servers to provision. I that case automation beyond simple Bash scripts is a must - time to meet Chef.
You are working currently on that awesome app and just started thinking about implementing new feature, let’s call it feature X. What’s the first thing you do? Rolling your own solution or… maybe checking if there’s a magical gem that can help you solve that problem? Ok, it turns out there’s already a gem Y that does what you expect. Also, it does tons of other things and is really complex. After some time your app breaks, something is definitively not working and it seems that gem Y is responsible for that. So you read all the issues on Github, pull requests and even read the source code and finally find a little bug. You managed to do some monkeypatching first and then send pull request for a small fix and solved a problem, which took you a few hours. Looks like a problem is solved. And then, you try to update Rails to2 the current version. Seems like there’s a dependency problem - gem Y depends on previous version of Rails…
Last time, in part 1, I was giving some advice about testing - why to test at all, which tests are valuable and which are not, when to write acceptance tests and in what cases aim for the maximum code coverage. It brought about some serious discussion about testing ideas and if you haven’t read it yet, you should probably check (it) it out. Giving some general point of view about such broad topic like Test Driven Development / Behavior Driven Development is definetely not enough so I will try to apply these techniques by implementing a concrete feature. I wanted to choose some popular usecase so that most developers will have an opinion how they would approach it. In most applications you will probably need:
Testing is still one of the hottest topics when it comes to developing maintainable and business-critical applications. Ruby on Rails community embraces the importance of writings tests, yet there are so little resources about the Test-Driven Development or Behavior-Driven Development in Rails applications from a wider perspective. How should we test our application? Which tests are valuable and which don’t provide any value? What scenarios should be included in acceptance tests?
There’ve been a lot of discussions recently about applying Object Oriented Programming in Rails applications, how ActiveRecord callbacks make testing painful and how Rails makes it hard to do OOP the right way. Is it really true? Rails makes everything easy - you can easily write terrible code, which will be a maintenance nightmare, but is also easy to apply good practices, especially with available gems. What is the good way then to extract logic in Rails applications and the best place to put it?
You’ve just setup your production server, but still haven’t deployed your app? Then this the right place for you. You are going to learn how to deploy your app to remote server, deal with some config files, create staging environment and setup monitoring tools.
Server setup with the entire environment for Rails applications can be quite tricky, especially when you do it for the first time. Here is step by step guide how to setup CentOS 6.4 server with a basic environment for deploying Rails applications. I encourage you to choose CentOS Linux - it is a reliable distro (well, based on Red Hat Enterprise Linux), easy to handle and doesn’t require advanced Unix knowledge like Gentoo (especially while updating system related stuff).