I have an idea for a large web application, which in my mind would really be a number of reasonably independent application "components" (?), e.g. forum, blog etc.
It seems to me that it would be nice to open source some of the individual components for others, or myself in the future to use.
Now clearly, I could write a basic forum, make the code available, then copy it across into my large app and extend/integrate it. However, this doesn't feel very DRY. In an ideal world I could maintain the code in one place and drop it into my larger application.
Rails seems to include engines, which sound like solve my problem but it would appear that what I want to do is a bad idea!
So should I..
a) Just build one large, coupled app.
b) Create a rails forum app (for example), release it, then merge/copy it into my main app
c) Use engines
d) Other...
Cheers,
Adam
That warning is just the standard Uncle Ben Corollary. Paraphrased from "With great power, also comes great responsibility." to "Just because you can, doesn't mean you should."
However, just because there are a number of uses for engines that are bad ideas, that doesn't mean it is in your case. Blogs and forums are two reasonably independent components that have already been produced as plugins using Engines. You might not even need to make them.
The way I see it, if you're planning on reusing a functional component that you can feasibly segregate from the rest of the app, then that's a good enough reason to make it a plugin, whether or not it relies on engines.
My experience is that these plugins grow from existing application code I've written. It's much easier to conceive, write, and test them as part of an application than on their own. Engines being miniature apps, aren't that much harder to build and test.
In short. Only you can decide which path is best, because you are most familiar with the goals of your app. Before you start have a look at what others have done with engines and plugins. The components you want to build may already exist.
To answer the question, I would probably start by building a single app, and extract out the bits that could be useful in other apps and abstract them into [engine] plugins as they reach maturity.
What you might be looking for Git Submodules. I don't know a ton about them, but you can simply have a git repo within a git repo. And you can update all your inner git repos pretty easily. Here's an article talking about it.
Related
soliciting advice about upgrading (or re-writing?) a legacy app. It's a single page webapp with lots of dynamically generated windows and forms, roughly comprised of
13,000 lines in .rb files
11,000 lines in .erb files
25,000 lines of javascript (not including large 3rd party libraries that bring this to nearer 60000 lines)
This acts as a UI for end users of our system, which also has a number of core business services (mostly written in Java, with a small amount of Node.js) and a fairly sizeable MySQL database (>200GB). Some of these services push AJAX to the client browser for real-time updates.
Reasons for upgrade
It's ruby 1.8.7, rails 2.3.15. Most of the core code dates from 2009. This makes it both insecure and hard to maintain (think "predates the existence of gemfiles".)
The app has been maintained by Java devs for most of its life, as most of the company's devs have been hired as Java devs to work on all the other services that perform business logic. It's probably safe to assume that this has lead to lots of hacks from people who didn't want to break anything, and certainly lots will not be done in a "rails way".
The javascript is also a bit of a mess. It's got a knot of frameworks (the original Angular is used sporadically; jquery and prototype are both fighting over the $ symbol in different places.) There are files that are 7000 lines long.
the css styling has been upgraded since 2009(!) but is starting to look a little tired. We'd like to implement a bootstrap theme that will look sharp without too much front-end skill, but right now the code that renders all of our pop-up windows, sidebars etc breaks badly if we try and add bootstrap.
It would be nice to modernise our push servers, replacing them with websockets.
Context
There are 3 of us on the dev team- this is my first job, and I've only been here since January. Of the other two, one has only been here about 4 months longer than me, and it's his first dev job too. The other guy is the only one who has ever spoken to someone who spoke to someone from the original team.
Oh, and of course we have little or no test coverage.
Options
When I was hired (as a Java developer), I was told that we were looking to replace the website with one based on Spring MVC. This effort is partially underway, having been attacked in drips and drabs over a couple of years. Because different devs who never met have attacked it as if it's their own brand new project, the same problems are solved in different ways in different places. They've tried some flashy techniques such as custom annotations that I find hard to follow, but as far as I can tell don't fully work. The most senior of us estimates it would take our team a year's dedicated full-time work to finish it (which is not a realistic business proposition, based on how many requests for new features we get from customers).
I'm inclined to upgrade the website rather than spin out a new one. This is partly because I can see the sense in that post. Another reason is that we're all employed as jack-of-all trade full stack developers (doubling as DBAs, sysadmins, etc...). We've got no particular expertise in UI design, and the UI for our present interface, although dated, is pretty user-friendly; it feels like a blank canvas would throw that structure out, and play to our weaknesses. Upgrading ruby/rails would also make any features we add during the upgrade much easier to add to the new site.
Apparently some experienced ruby devs who are friends with my boss have advised him informally it'd be so much work to bring the website up to date that it would be comparable to a complete re-write, which was the motivation for the spring project. This would have the advantage of only having to think about Java + javascript, and not trying to hire people who know both Java and ruby well.
Conventional wisdom seems to be upgrade rails in stages. I'm not sure how well this would work for us, for 2 reasons. For one thing, there 3 major versions for us to upgrade, which might have significant changes between them. More importantly, the code needs some TLC anyway with refactoring and the creation of a test suite.
I'm inclined to follow the following strategy:
Invest some developer time in training, to get a sense of the relevant best practises and the "rails ways" of doing things, rather than the "good enough to hack" knowledge most of us have now.
fire up a new rails 5.1 project on ruby 2.4.0
Configure active record to use our old database
Copy across the javascript from the public folder of the existing project in to the relevant parts of the asset pipeline and save that headache for "phase 2".
Sort out a gemfile with updated versions of our dependencies (for example, mysql gem has been replaced by a mysql2 gem.) Installing rubocop seems like a good idea at this point.
Copy files across from old to new project one at a time. Read the code, figure out what it's doing, write the relevant tests, fix where they break. Use the ruby API and rails upgrade guides to update the syntax. Refactor until rubocop is appeased.
Once we've reproduced the functionality of the existing site, write a new stackoverflow post on how to sort out the javascript ;)
This certainly sounds like a lot of work, but seems less likely to produce a buggy mess than trying to reproduce our existing functionality from scratch in a different language. So...
Questions
Does this strategy seem sensible? Is this a case where the re-write is really a better option? Is tackling the JS separately the best call, or is it better to restructure it as we're examining the calls to it from the views? Or should we really upgrade -> 3.0, 3.1, ... 5.0, 5.1?
We've altered the database manually, adding new tables, new fields and whatnot directly rather than using .rails generate. 'Rails magic' seems to make this work at present, but should we anticipate problems in step 3?
Is there any logical order in which to approach the migration of ruby? As there's major changes to the routing, which is the central entry point of the application, it seems sensible to start there, followed by authentication, then the main page, and then add functions one at a time.
Part of the problem is "not knowing what we don't know" about the rails way of doing things. Apart from the canonical Ruby/Rails tutorials (Hartl, Ruby Monk, Ruby Koans, Kehoe's rails book), is there any essential reading we should be aware of before trying to take on such a large job? I'm especially thinking about things that may not be immediately obvious, like proper use of helper functions, module structure, etc.
Any other advice, comments, prayers, ... welcome!
I have some community running Drupal 6. Drupal 6 have great numbers of modules for what I need, plus word "Community plumbing".
I've tried PHP frameworks like Yii, but I dont like PHP-CLI, because I feel that not well integrated with the PHP itself. So, I stay with Drupal 6 with lots of hacks.
But Drupal now become more "CMS", more "Enterprise" (just like lots of Java CMS).
With Drupal 7, out of the box, it easier to make a newspaper site, but to me, it more difficult to tailored to my needs, it more magic, and also slower.
The word "Community plumbing" has been replaced with "Open Source CMS", with statement "Use Drupal to build everything from personal blogs to enterprise applications". This is scares me as community-based application developer.
Django looks promising, but Rails have much more open source kick-ass app avaiable.
I dont know anything about Drupal 8. I dont know what to do for my next development.
It sounds like you are looking to move from a CMS to a framework. I am not going to give advise on frameworks here, since there are numerous topics on SO that cover this already.
A few things you should realize, coming from Drupal, moving to a (RAD)framework are the following:
Drupal is not OO, has its own ways of using PHP (hooks, template overrides) and such. Expect the experience to be very different. Your Drupal-gained-knowledge may come in handy, but is often of little use in framework-land where OO is the alpha and omega. :)
Drupal takes a lot from your hands. By installing some module, you have a new feature. With frameworks you are all on your own in this. You should select a framework that works with gems, packages or modules itself if you want to stand on shoulders of others peoples work. The main difference between these libraries and Drupal modules, is that you will have to implement and integrate the libs yourself. I consider that a very good thing, since it makes no assumptions up front and allows you to build exactly what you had in mind, yet having the same experience as Drupal-modules: many things are already done for you.
You know PHP. You probably don't know Python or Ruby as well. That means PHP-based frameworks have an advantage for you. But read various posts on SO about the downsides of PHP used in Frameworks to see some reasons why learning a new language and environemnt is not all that bad.
All in all, I think you will be surprised byt the increase in development-efficiency when coming from Drupal into a framework.
Make your own CMS in 'just PHP' and go back to being happy and having fun coding all day long :)
More people than you have noticed this behavior of leaving developers that have supported a system for years and years with a take it or leave it option.
It seems all the big companies can do with a product is make it 'bigger'. More convoluted, automated, with more layers of code and less modularity - all in the aim to make 'the ultimate megaglobular ultrauniversecorporate site'. Almost as if small clients with 'just a website' don't exist. Enterprise products belong in the enterprise domain. When you upgrade a non-'do the mightiest world-spanning web site/application' system, you shouldn't get a 'do the mightiest world-spanning web site/application'system.
The bigger system may be able to do more things and be more scalable to large systems, but they leave behind no small, accurate tool to do small and medium jobs quickly and with ease. Also: "Documentation is not scalable" (c) H. Erlandsson. To even find the doItAll() function or even know it exists, you have to wade through increasingly huge documentation. To then learn how to use it correctly, if you don't know all the component the function builds on, you have learn the behavior of many subsystems to understand how to apply some terse declaration to your problem.
The ultimate something can be several refined gems, and not an asteroid-size cluster of crystals.
Was a bit tricky to read out exactly what you're asking, hope I read you right. I can recommend some programming system gems, but they are not in the web dev domain, maybe others will know a few :)
I'm going to develop a collaborative site, and one of the features will be collaborative editing with realtime changes. i.e. when two or more users are editing the same doc, they can see each other changes as soon as they happen.
I have some experience with Ruby on Rails, so I was thinking about using EventMachine, but with all this hype around Node.js, I am know considering using it instead. So, what would be the main benefits of using Node.js instead of EventMachine?
tl;dr
What are the main differences between EventMachine and Node.js (besides the language)?
EventMachine has nothing to do with Rails apart from them both being written in the same language. You can get EventMachine as bare as Node.js; all you have to do is not add libraries to your project. In my experience the EventMachine libraries (like em-http) are much nicer than anything for Node. And you can use fibers instead of callbacks to avoid callback hell. Complete exception handling is pretty much impossible in Node because of all the callbacks. Plus Ruby is a nicer, more complete language than Javascript.
I tend towards the "use what you know" (even if it's a heavier architecture). Because of that, I don't see it being quite as simple as "EventMachine vs NodeJS." Mainly, the difference can be summarized as this:
NodeJS is a framework/language that was written to handle event based programming in JavaScript. That is its driving force. It's not an after thought, or a third party mechanism. It's baked right in to the language. You create callbacks/events because that's how the language is built. It's not a third party plug in, and doesn't alter your workflow.
EventMachine is a gem in Ruby that gives developers access to some of the goodness of the event based programming model. It's heavily used and well tested, but not baked directly in to the language. Both are locked to one CPU, but with event programming at Nodes core, it still has a leg up. Ruby wasn't written with concurrency in mind.
That said, technical problems can be overcome. The more important questions (from my view) that should guide your decision are these:
What will your production environment look like? Do you have complete control over the server? Can you host it however you want? Or will it be on a shared system to start with, and then you have to expand on that?
Do all the developers on your team have the ability to learn a new language very fast? How fast will they be able to understand an event-based language like JavaScript for the middle tier?
Do you need all of the architecture that Rails gives you (full Testing framework, scaffolding, models, controllers, etc)? Or is that overkill?
There are quite a few technical differences between the two. One is a language, one is a framework. Really, how heavy of a stack you want to run? How much learning will your developers have to do? Do you want a full stack the gives you a lot of niceties, that you may not use, or do you want a bare bones set up that runs extremely fast and concurrent, even though you may have to write extra boiler plate code and learn a new lanugage?
While Rails is not as heavy as some web application architectures, you're still going to need more processor power than you would to handle a similar amount of throughput in NodeJS. Assuming quality code for both systems. Bad code written on either stack is going to prevent the stack from shining. It really comes down to- Do you really want to learn a whole new way of doing things, or utilize your current understanding of Ruby to get things off the ground fast?
I know it's not really a definitive answer, but I hope this helps guide you to a decision!
One thing worth mentioning is the production story. EM, like most Rack stuff, has plenty of testing and monitoring tools available that are well tested, whereas Node.js falls well short in this respect.
At the time of writing, it seems almost impossible to get clear metrics from Node to answer questions like 'Do I need to scale'. There are options starting to form out there from the likes of Joyent, and always the roll-your-own argument, but nothing anywhere near tools such as NewRelic.
Node.js is very good from a performance / configurability point of view, but personally I wouldn't host it in production just yet.
Node.js
You get far better control low level control over what's going in. You can include general libraries to build on top of node.js to tweak your level of abstraction to your own liking. For example you can use connect or express depending on whether you want a view engine written for you.
You can use socket.io or now depending on how much you want your client-server connection abstracted. You can opt to include any of numerous MVC libraries or write your own.
Event-Machine
An asynchronous IO library just like node.js
It comes down to a Ruby vs JavaScript preference, how much flexibility you want with abstractions or lack of abstractions and whether you want to use node as your actual web server.
a detailed view at confusion has already been proposed... just a personal view
[] node.js will be better, if you are ready to learn and experiment more than you think because:
it's thread mechanism is awesome (inspired from that of 'erlang')
you can build a purpose specific server (easily) which will be real productive
For the first time I'm creating a quite complex Rails app.
I'd like to know what's the best way to organize that app by folders. Until now, I'd do everything under one app (all the models, controllers, etC) but reading some open source code I realize that they put everything under different apps.
Like for example Spree Commerce. They have a general folder and inside that they have different apps (API, core, admin, etc). How is that done and is that the best way to do it?
I'd like to get pointed to the best way to do it (a book, blog, anything) so I can understand how I can architect my app for future maintenance.
thank you
As an aside I think the title of your question is a little confusing. Rails, by using convention over configuration, defines 'how to organise a Rails app'. I think your question is rather about how to architect your application as opposed to anything Rails-specific. Maybe tweak the title?
That aside, without knowing any more detail about your project it's a tricky question to answer, but I'll give it a go.
All applications should start off simple, if you believe (like I do) that you should start by building the simplest thing that could possibly work. Given this, since you're using Rails, then in all likelihood the simplest thing would be to structure your app as a vanilla Rails 3 application. This will probably (I say 'probably' because I don't know any specifics about the app) allow you to get a beta version of your app up and running pretty quickly without worrying about complexities which at this stage in the development of your project are not a problem.
If you need to create an XML or JSON-based API then Rails makes this really easy using the standard framework, which will allow you to spend more time thinking about the API design than how to code it, and it's the API design which is the most important thing to get right in the first instance.
Similarly, your Admin site can be part of the same app just in a different namespace. If you find later down the line that you want it as a separate app, you can do this (maybe you could use the awesome API you designed to facilitate this), but why bother designing it with this added complexity (and hence extended development time) in the first place if you don't have a good reason for doing so?
Once you have your app up and running and people are starting to use it, you start to get a picture of where the bottlenecks are and where the design could be improved. At this stage, if there's a need, you can start to move parts of the app to scalable solutions, such as running your API as a standalone service, introducing caching, changing data stores and other improvements and optimisations.
Even if your app is as wildly successful (and I hope it is!) then re-architecting your application whist continuing to run the existing service is still entirely possible, as Twitter have proved. Just stick to Knuth's statement and you'll be alright.
Regarding reading material, that's a tricky one. For me a lot of the XP and agile development classics taught me a huge amount about how to approach program and app design. I'd also check this StackOverflow topic for book inspiration.
Good luck!
Spree uses Rails' Railties (Rails::Engines). Railties are introduced in Rails 3 to make it more modular and easy to extend. Rails 3 itself is a collection of Railties (ActiveSupport, ActiveModel, ActiveRecord, etc.).
If you are developing a complex app I would suggest spending some time planing its' architecture. Designing a complex app without any initial planning would definitely end with a maintenance nightmare down the road. It also introduces a huge learning curve for the new team members, slow down your new feature introduction and of course, frustration.
Anyway, don't over optimize, but don't forget to design your architecture for your needs.
IMHO, I will create very complex projects as one app. I have reason to believe that Spree and Radiant build under seperate apps so that under the pretense of their open source communities, contributors can contribute code easily without tampering with the core data, and the core workings of the application.
Otherwise, you should be alright just building it as one app. Just keep it neat.
Here is what have kept me sane for several years of RoR development:
I use Rails Engines, but keep them in same codebase as the main app. Here is good starter for modular Rails app:
https://github.com/shageman/the_next_big_thing
Wherever I can I try to reduce coupling and use composition to make things easily testable, reusable and maintainable. This helps to eventually extract module or engine as separate gem. Composition is done by routes (mounting), directory overlaying (assets), dependency injection or configuration.
If I don't need to re-use an engine I put it in the same code base as the main app which is single deployment unit. Thanks to that I don't need to switch between projects in my IDE. While in development environment any changes to the engine code are instantly picked up by Rails reload mechanism.
What language, framework, and hosting considerations should one make before starting development of a scalable web application?
The most important consideration is not to over-engineer to the point that it gets in the way of building and launching something. Analysis paralysis is the single biggest inhibitor to productivity, progress and results.
Yes, do some planning. Pick a framework. Perfection in a framework will be impossible to find because it doesn't exist, partially because you don't know what you need until you build it anyways. Chances are, if you pick something, it will be better than picking nothing.
Yes, try to pick flexible, inter-operable tools for where you see yourself going.
Yes, look for a good built-in feature set where you see yourself going in the next 6-18 Months. Trying to look beyond that is not really realistic anyways as most projects change so much anyways going towards the first release.
So, pick what you're comfortable with or what is familiar. Don't follow the crowd, do what gets you the best results, quickest, and often. Understand that you might have to change in the future. So, whatever you build now, try to use unit testing so you can re-factor if ever needed.
If what you're building is going to be super successful, it will be a great problem to have, and an easy one to work on once it's making money as you'll be able to get other talent to help you.
Share what you end up picking and why for your situation -- it helps the us learn from you too!
Don't necessarily marry yourself to one language or framework. It may be that some parts of your site work better with different languages and frameworks than others. For example, all of 37signals' sites are based on Ruby on Rails, but they recently wrote a blog post about how the underlying technology of one is actually written in Erlang now because it's much easier to do concurrency that way.
Obviously there's a level of complexity where things turn into a mishmash, but using the right tool for the job — even if that means different tools for different jobs — can simplify things.
Firstly on language, it largely doesn't matter. PHP, Java and .Net being probably the biggest three are all proven in the sense that they run some of the largest sites on the Web so don't listen to anyone who tells you one is more suited than any of the others.
Some might also put Ruby and Django/Python in this list. I have nothing against them but I'm not aware of any big (say top 50) sites using either.
Hosting considerations depend on how low you want to start but basically the order is:
Shared;
Virtual Private Server;
Dedicated.
Scalability will largely be about your application's design than any language, framework or provider. Efficient database schema, efficient delivery and use of Javascript/CSS and in-memory caching are all issues common to any language or framework.
Language - I'd recommend something with good frameworks and good testing libraries like Perl or Java.
Framework - it depends on what do you plan to do. If you start with a hosting that does not allow FastCGI, it is best to avoid such frameworks like Catalyst or Rails. That's why I love CGI::Application (primarily Perl, but ported to other languages too) - it can run as CGI, FastCGI or mod_perl. For development it can be run from it's own web server.
Hosting - nothing is better than you own server. It can be your own server, leased server or virtual server. But you can start with cheapest hosting and when you need more, you should be able to afford it.
It depends.
Start by looking at your requirements (Functional or user defined) (Non Functional - aspects that describe your desired system link text)
Next I would clarify what it means to have a scalable web application. Define it as test cases that can be clearly tested (must support X page views / second with response time < Y seconds).
Once I had those pieces in place I would look at what type of skills my development team can support (for the intial project and on going maintenance). Then find some case studies of applications out in the wild that use similar language or framework. If someone else has made a specific language / framework scale then chances are good that you can too.
Finally go out and look for some hosting providers that support your chosen language, framework and requirements.