# Multiple applications to reduce complexity but how to intera **URL:** \ **Category:** Rails\ **Created:** [April 23, 2006, 4:32pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161 "2006-04-23T16:32:10Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 4:32pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/1 "2006-04-23T16:32:10Z")
Hi, we are building couple of application that will need to communicate with each other, because there where special in what they do, I will explain it with some general application: For example, you have a projectmanagement application, where you can store messages, milestones, enc, and you have a online time registration application. Now you want to be able to setup the task for each milestone in the timeregistration application but still have a projectmanagement application for client that don’t need the time registration. Why do we want to split it up? - easy interface - application focused on one task What do we want to achive? - integration when having multiple subscription in different apps How can we achive this? - option 1: use the same database and make one big application (we think this make developing complicated) - option 2: use the same database, models but implement the logic again (mhhh, not in favor of that) - option 3: let the application handle the integration by directing it to the secondary application, that application should direct it back when its done (look like the best alternative) - option 4: use the application api to communicate between apps (rails doesn’t have a good way of handeling services or am I wrong?) How have you done it? what are your ideas? Greets, Abdur-Rahman ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 4:56pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/2 "2006-04-23T16:56:59Z")
On Sun, Apr 23, 2006 at 04:29:16PM +0200, Abdur-Rahman A. wrote: […] } Why do we want to split it up? } - easy interface } - application focused on one task } } What do we want to achive? } - integration when having multiple subscription in different apps This is very clearly stated. Kudos for asking a question well. That said, all of the following choices are plausible, but some are better than others. } How can we achive this? } - option 1: use the same database and make one big application (we think } this make developing complicated) You can also have one big application with multiple databases. I don’t have the Agile book in front of me, but I know it is possible to set up subclasses of ActiveRecord::Base that each define their own database connection, and have your models subclass the appropriate one of those. It is also possible to split out your models into modules, to keep the major pieces of your application separate. Controllers can likewise be placed in modules. } - option 2: use the same database, models but implement the logic again } (mhhh, not in favor of that) I’m not quite clear on what you mean by this approach, but repeating yourself is never a good idea. It is, however, possible to share code between separate applications, just as you can share code between scripts with additional Ruby libraries (e.g. gems). } - option 3: let the application handle the integration by directing it } to the secondary application, that application should direct it back } when its done (look like the best alternative) If your system is sufficiently separable to do this, it definitely sounds good. It does have some hard limitations, however, so you should be sure your application will never need to go beyond them before taking this approach. } - option 4: use the application api to communicate between apps (rails } doesn’t have a good way of handeling services or am I wrong?) Actually, Rails supports web services quite nicely. It’s probably overkill for several applications that are likely to be running on the same server. On the other hand, this is the most scalable solution since you can move your individual applications to separate machines without disrupting the system as a whole. } How have you done it? what are your ideas? } Greets, } Abdur-Rahman –Greg ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 6:41pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/3 "2006-04-23T18:41:54Z")
Well, I really want to know (I am sorry for being unclear) what worked for people in practice 🙂 How have you done it? and why? Thnx, Abdul ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 6:48pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/4 "2006-04-23T18:48:09Z")
On Sun, Apr 23, 2006 at 06:38:45PM +0200, Abdur-Rahman A. wrote: } Well, I really want to know (I am sorry for being unclear) what worked } for people in practice 🙂 How have you done it? and why? Ah, you are looking for case studies. Unfortunately, I can’t help you there. I have not yet been in a position where I needed to create a huge app. } Thnx, } Abdul –Greg } Gregory S. wrote: } \>On Sun, Apr 23, 2006 at 04:29:16PM +0200, Abdur-Rahman A. wrote: } \>[…] } \>} Why do we want to split it up? } \>} - easy interface } \>} - application focused on one task } \>} } \>} What do we want to achive? } \>} - integration when having multiple subscription in different apps } \> } \>This is very clearly stated. Kudos for asking a question well. That said, } \>all of the following choices are plausible, but some are better than } \>others. } \> } \>} How can we achive this? } \>} - option 1: use the same database and make one big application (we think } \>} this make developing complicated) } \> } \>You can also have one big application with multiple databases. I don’t have } \>the Agile book in front of me, but I know it is possible to set up } \>subclasses of ActiveRecord::Base that each define their own database } \>connection, and have your models subclass the appropriate one of those. } \> } \>It is also possible to split out your models into modules, to keep the } \>major pieces of your application separate. Controllers can likewise be } \>placed in modules. } \> } \>} - option 2: use the same database, models but implement the logic again } \>} (mhhh, not in favor of that) } \> } \>I’m not quite clear on what you mean by this approach, but repeating } \>yourself is never a good idea. It is, however, possible to share code } \>between separate applications, just as you can share code between scripts } \>with additional Ruby libraries (e.g. gems). } \> } \>} - option 3: let the application handle the integration by directing it } \>} to the secondary application, that application should direct it back } \>} when its done (look like the best alternative) } \> } \>If your system is sufficiently separable to do this, it definitely sounds } \>good. It does have some hard limitations, however, so you should be sure } \>your application will never need to go beyond them before taking this } \>approach. } \> } \>} - option 4: use the application api to communicate between apps (rails } \>} doesn’t have a good way of handeling services or am I wrong?) } \> } \>Actually, Rails supports web services quite nicely. It’s probably overkill } \>for several applications that are likely to be running on the same server. } \>On the other hand, this is the most scalable solution since you can move } \>your individual applications to separate machines without disrupting the } \>system as a whole. } \> } \>} How have you done it? what are your ideas? } \>} Greets, } \>} Abdur-Rahman } \>–Greg } \> } \>\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ } \>Rails mailing list } \>removed\_email\_address@domain.invalid } \>[http://lists.rubyonrails.org/mailman/listinfo/rails](http://lists.rubyonrails.org/mailman/listinfo/rails) } \> } \> } } ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 7:57pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/5 "2006-04-23T19:57:07Z")
Ray, Tnx for your feedback, yes we are currently in a situation where 5 applications have been developed than need to be merged into one application, when we started developing we expected to do this. But know we are reconsidering, maintaining one application is already very complex, maintaining one big integrated application is much more complex. How have the peepz at 37s solved this? they have multiple applications but still an integration. Greets, Abdul p.s. the pm/timeregistration was only an example, we are not creating an other application suite that aims at serving that market ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 7:41pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/6 "2006-04-23T19:41:03Z")
Abdur-Rahman A. wrote: > For example, you have a projectmanagement application, where you can > store messages, milestones, enc, and you have a online time registration > application. Now you want to be able to setup the task for each > milestone in the timeregistration application but still have a > projectmanagement application for client that don’t need the time > registration. > > Why do we want to split it up? > > - easy interface > - application focused on one task I’m not convinced that this is a good idea. A large fraction of the enterprise software development is trying to do the reverse, combine two or more separate software applications into one. Rails can easily handle giving you separate controllers and views so that the interface works well in the different use cases you mention and is modular enough that the parts of the application will be decoupled for ease of development. Second, it is premature to be asking the question at this point. Are you sure you are trying to solve a real problem? Perhaps one large app would be complicated, but I would bet that having two or three applications intercommunicating would be even more complicated. In your scenario, isn’t there going to be some notion of roles? Client A can only see projects belonging to Client A, Manager Employee B can see projects belonging to all Clients, and Employee C can see projects belonging to Clients Q, R and S and can only complete tasks belonging to Client S’ Project W. This means that you are going have to either have a separate authentication module on your project and time applications, or you are going to have to pass not only the fact of being authenticated, but also the detailed credentials back to the project and time apps. At that point, wouldn’t it be simpler just to have a single app? > when its done (look like the best alternative) > > - option 4: use the application api to communicate between apps (rails > doesn’t have a good way of handeling services or am I wrong?) > > How have you done it? what are your ideas? Here is how I’d do it. Start by developing the project management portion of the application. Once you have an idea what that looks like you can start to add the timekeeping functionality. Add in authentication and user specific customizations as necessary. If it ever becomes necessary to separate the applications, you will be the expert on what the pain points are in your application and you will be in a better position to evaluate and implement possible solutions. – Ray ---
**Author:** ![abdurrahman](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/dec6dc/32.png) [@abdurrahman](https://www.ruby-forum.com/u/abdurrahman)\ **Post date:** [April 23, 2006, 7:58pm UTC](https://www.ruby-forum.com/t/multiple-applications-to-reduce-complexity-but-how-to-intera/94161/7 "2006-04-23T19:58:26Z")
Ray B. wrote: > Abdur-Rahman A. wrote: > > At that point, wouldn’t it be simpler just to have a single app? I agree that you are better off with one app. Rails makes it easy to keep things encapsulated and organized.