How to decompose a Rails app into different small apps ecosystem - ruby-on-rails

My team has been developing a bunch of modules in a monolithic Rails app for internal use. The modules are for example leave request, staff info, tasks/todo etc. Each module has its own purpose but somehow is linked to common information such as staff profile and user authentication. Each module has a developer assigned and they commit code to the same Rails app. Currently, it's super hard to maintain the code and scale. Now, I'm doing my research to decompose the app into small distributed apps and make them an ecosystem. Here are the concept I'm looking for:
There should be a master app that maintain the views of other client apps. Better yet, it acts as a platform for other client apps to plug in to it. Staff logs in to this master app to access client app.
Master app should render views of client app using AJAX or other ways (not decided).
Although, I want to decompose the apps, but each app should still be able to query resources/data such as staff profile from other client app in the ecosystem.
Actually, I have not decided about the interaction of each app. Thinking to us RESTful (not decided).
It should support development environment where each developer can develop each app independently. Hence, maintaining their own code in their own git repository. This is probably the main purpose of decomposing the app in the first place.
I'm reading Service-Oriented Design with Ruby on Rails book, but it seems like they focus on decomposing an app into small different services, whereas I want to have small different apps. Just wondering if there's any other ways to do.
Sorry for a long question and asking too much. Just want to know if you have been in the same situation and can guide me to some articles, communities, books so that I can continue more on my research.

Ah the joys of refactoring. It can be a tricky dance trying to structure an application into logical groups so that parts can be decoupled.
I would strongly suggest looking into Engines, with the Engines vs Mountable being very informative. This allows you to build a mini Rails app (aka an Engine) that can be packaged as gem. The custom Engine gems are bundled into a Rails app, providing a complete set of configurable functionality (models, controllers, views, etc).
The usefulness of Service-Oriented Architecture depends a lot on what kind of data you are pushing and pulling around. That being said, Rails is really wired for RESTful, so you get a lot of bang for the buck with that route.

Related

Rails separate app or engine

I have an app and I would like to build an admin management system for it that would be using the same database and probably even models. I want to keep it separate from an app but because I want to use share models between the two, I'm debating wether to use an engine or build a separate app?
One reason I'm more inclined towards a separate app is because I can deploy it separately without affecting the main app.
Any suggestions, opinions or experience?
Thanks!
I would definitely recommend engines. Spree E-commerce is a very good example of separating a single app into engines representing core, frontend and backend. And it is very clear and handy in support.
https://github.com/spree/spree
I would place the shared models, migrations & code in an engine and use it in two applications: the admin app and the normal app. You might find these useful:
https://github.com/EPI-USE-Labs/activesupport-decorators
http://pivotallabs.com/leave-your-migrations-in-your-rails-engines/

How to implement data visualization in ruby / ruby on rails using R?

Disclaimer: We're a collection of scientists that are just now getting into python/ruby.
Project summary: We have analytics and usage data from social networking sites that we are using R and Highcharts (via lazy_high_chart gem) to present analytics to users through a website. The user can interact with this data by specifying which and when they want to investigate a social media segment. So the user defines the subject and the website responds with a slew of metrics.
Problem: So far we have been using straight ruby to pull social networking data (one class), send it to the analytics engine (another class), and present it in plotted glory (final class). However, this is all been proof of principle and console driven so it seems inefficient to push it to a site from this start. Should we have started from the ground up with a rails framework and just built the site with all of these analytic engines built into the site? Or...is it better to have this backend pipeline written in ruby that only interfaces with a rails framework trough yet another object?
A suggestion or pointer to a general document that hints on how to integrate backend data crunching with frontend rails would be great.
Your question is basically how to architecture the system, and this is somewhat hard answer since it usually depends on a lot of things: system requirements, application landscape, project planning, skills, etc.
But just looking at the two alternatives you mentioned, I think there's nothing wrong with creating a fresh Rails application, copying your prototype modules into the lib/ directory and connecting things the standard way. You can use rake tasks to keep the console interface you already have. In the end, your setup looks quite similar to a standard web application. (Usually you have a database doing the "data crunching", in your case it is the R engine.)
I don't know any specific documentation about integration Rails with R, but some research about general system integration with Rails should give you a good starting point. (However, this would only be needed if you really want to build two independent systems.)

Rails application architecture and common setup

So I am starting out on company project that will have several components:
At first...
Job list
Client profile creation and management
User administration and access (login, signup, roles, etc)
later...
Messaging
Schedule
Basic reporting
way later...
Deeper analysis and bi
I'm wondering if it makes sense for each bullet item to be its own rails project, self contained and modular (if that is indeed the case); or if it's just best for it to be in the same app. I could envision a situation where each module could operate so independently of each other that it wouldn't need the rest (except for the user funcionality) and another situation where all modules would be used together.
It seems like to me that many tasks can be handled with a lighter framework like Sinatra (and then situated physically under the rails app). It also seems like it would be a lot of overhead to have several rails apps running on a server. But I am not totally aware of all the pluses and minuses to operating each scenario.
I know this is kind of a general question that is bound to get a lot of "it depends" kind of responses (and rightfully so) I was looking for opinions/examples of how you setup this kind/your kind of project in rails. I am a quasi noob so be gentle.
Thanks in advance!
Generally speaking I would consider a website to be a suitable target for a Rails app. Each part of the app can have its own namespaces within the app, so the app has some structure internally, but they should all be one application. Consider things like sessions, where you want a user to login and use whatever features of the site you want. You want those sessions in one application without a user having to login to different sections.
Saying that, if there is complex or extended functionality that isn't part of the MVC architecture (say talking to an external API, data-mining etc), then you could offset that to a separate project and a include it as a Gem in your application. You would still have one main Rails application that includes those Gems.
You might also want to bundle together a section of your project into a reusable Rails engine that can be loaded into multiple projects. For example, Devise handles user login and management. It is a Rails engine, bundled as a Gem, that you include in your project.
Another example from Meducation (one of my sites). I'm in the process of extracting our email tracking system out into its own Rails engine as I feel its functionality sits alongside Meducation and is not a core part of it. I can then use it in other projects as well.
In your specific example, I think your requirements fit fine in one Rails application.

Rails Authentication via Web Service

So, this may be a kind of dumb question, but I checked the Google and got no hits. We want to host multiple Rails apps in a way that makes them look homogeneous. We want all the apps to have the same look and feel, and all the apps to use the same sign-on database.
Theming I think we could accomplish by just putting the site theme into a gem, and requiring that gem from our github repository in each app. However, auth is trickier.
I know that I can achieve this "for free" by just not making the different portions of the site (store, chat forums, etc.) different apps. If they're all, say, Rails Engines, we can basically drop them into the same application with their own namespaced routes, and have a single plugin that does auth.
However, for various reasons we'd like to keep these separate apps, if that's technically possible. The number one reason is scalability; since this will be a hosted site, we want the flexibility to spin up more instances of, say, the store (perhaps to handle a holiday sale rush), without needing to spin up the chat forums. Also, we want to be able to completely isolate the portions of the code that AREN'T intertwined.
Ideally, the databases would be separate too (keeping us from falling back into the rut of "put everything including the kitchen sink in the db"), but I do know that one "cheap" way to do cross-app auth is just to use the same plugin (say, Devise), and just point to the same DB.
So, I'm thinking that maybe the way to do this is to auth via a web service call. Is this prior art -- does anyone have a gem for this that "just works" so that authentication can be shared across all apps? Or am I just entering into a world of pain by trying to build things this way?
Thanks in advance!
You could do a single sign on approach described at:
http://blog.joshsoftware.com/2010/12/16/multiple-applications-with-devise-omniauth-and-single-sign-on/
The single sign on approach with oauth and devise has some drawbacks. The main problem I had was I was unable to extend the timeout time across multiple apps.

Spree as a mountable engine

So, we want to rearchitect a portion of our site as a Rails app. The original plan was to have a main "site" app, with a number of plugin apps (Rails 3.1 Engines) with compartmentalized functionality -- a store component, a social/forums/chat component, etc. Also, we wanted to put themes/styling in a gem so that our web designers could modify the site appearance and some minor layout tweaks without having to "know Rails." Initially, this was going well; we created the main architecture and plugins and the theme gem, and it was all playing nicely together; cross-cutting functionality like auth was put in the main "site" app and was consumable by the plugin apps, giving us a single sign-in for the site (a design requirement).
Our initial plan for the store component was to use the Spree (http://spreecommerce.com/) since it had, out of the box, 95% plus of the functionality we needed. However, there's a catch -- Spree is distributed as a mountable engine, but it's also an app. Meaning that not only does Spree mount inside an app (which is not a problem, in fact it's behavior we were counting on), but it depends upon being in control of the main app. Looking into the "why" for this behavior, it seems to depend upon two core pieces of functionality. The first chunk of functionality is some SEO permalink rewrite functionality that has to go into middleware; we could hack things so that our main app included this chunk of code (even though this would begin to entangle store functionality across our entire site, muddying the "Spree as a mountable engine" story... more on that in a moment).
More complicated is Spree's use of Deface to do theming and customization. While this is "clever" (note quotes), it really makes the integration of Spree kind of a nightmare; either you follow the path of least resistance and make Spree an entire store to itself (which completely breaks our story of "the store is just one part of our site, and plays nice with the rest of the site, including auth, theming, etc."), or you have to hack the hell out of Spree.
Not only that, but Spree doesn't follow the standard Rails Engine routing paradigm, where routes are isolated beneath an engine root (if you look in the lib's routes.rb file, you can see that it uses Rails.Application's routes, instead of an Engine's routes). This means that we couldn't have www.oursite.com/store/...all_the_spree_goodness, we'd have to have www.oursite.com/spree_owns_the_sites_routes...
So, has anyone else tried this? We LOVE Spree and would like to use it as our store. But it's starting to look that there's no real way to "integrate" it with the rest of our site aside from maybe some proxying magic with nginx or something like that (which is a separate nightmare, since we're hoping to host on Heroku, and then we have to figure out how to integrate multiple disparate apps into one DB -- for single sign-in auth -- and an HTTP front router).
Spree devs, we LOVE your code, but is there any work being done to make it an actual, for-real Rails Engine, as opposed to a stand-alone app that just happens to package all of its features into Engines? Without the ability to integrate it into an existing site (including not "owning" the app, being able to have all of its routes partitioned off, and so on), there's just no way we can use it :(
TIA.
I'm the Community Manager for Spree, so I think I may be able to answer your question.
Yes, there is work going on that will allow Spree to be a true Rails engine. In fact, that was my first task that I did when I was hired by Spree. The work is on the master branch (https://github.com/spree/spree) and we're looking to release this code as a 1.0.0.rc around Christmas time.
With this code, a couple of changes have been made. For starters, Spree is now a proper Rails engine meaning that you can now have it mounted at /spree or /shop or /whatever and Spree's cool with that. Secondly, all the models and other classes are namespaced so they won't conflict with anything in your application.
I'm not sure what you mean about Deface being "clever", though. What problems do you forsee with this? If you want to override an entire view you could do this by overriding the path in app/views/spree/products/show.html.erb. Mind you, this overrides the whole view, and if you only want to override a part of it that's when you'd use Deface.
Could you perhaps elaborate on the issues you're having with Deface? Would be interested to help you sort them out.
Thanks for using Spree!

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