Frameworks: All-in-One or Piece-by-Piece?

Software frameworks are great because they apply the principle of Separation of Concerns. A framework’s tools and code handle a specific need in a standard way for developers to write other code more easily. For example:

  • Web frameworks support receiving requests and sending responses.
  • Test frameworks include test case structure, runners, and reporting mechanisms.
  • Logging frameworks control how messages are gathered and stored.
  • Dependency injection frameworks create and manage object instances.

Recently, a question hit me: How far should a framework go to separate concerns? Should a framework try to do everything all-in-one, or should it behave more like a library that focuses on doing one thing well?

Let’s look at Python Web frameworks as an example. Django, the “Web framework for perfectionists with deadlines,” provides everything a developer could want out of the box. Flask, on the other hand, is a “microframework” that prides itself on minimalism: any extras must be handled by extensions or other packages. The differences between the two become clear when comparing some of their features:

Feature Django Flask
HTTP Requests and Routing Included Werkzeug (bundled)
Templates Included Jinja2 (bundled)
Forms Included None (Flask-WTF)
Object-Relational Mapping (ORM) Included None (SQLAlchemy)
Security Included None (Flask-Security)
Localization Included None (Flask-Babel)
Admin Interface Included None

Clearly, Django is all-in-one, while Flask is piece-by-piece. To make a serious Flask app, developers must pull in many extra pieces. There are many other frameworks with similar competitions:

  • JavaScript testing: Jasmine vs. Mocha
  • JavaScript development: Angular vs. React
  • Java BDD testing: Serenity vs. Cucumber-JVM

I think each approach has its merits. All-in-one frameworks are more convenient to use, especially for beginners. For developers who are new to a domain or just need to get something up fast, all-in-ones are the better choice. They come with all units already integrated together, and they often have good documentation. However, developing an all-in-one framework takes much more work because it covers multiple concerns. Developers may also feel shoehorned into the framework’s way of doing things. All-in-ones typically dictate what they believe to be the “best” solution.

Piece-by-piece frameworks require more expertise but offer greater flexibility. Developers can pick and choose the pieces they need, and they can change the packages used by the solution more easily. Found a better ORM? Not a problem. Need to localize the site in Chinese? Add it! Solutions can avoid excess weight and stay nimble for the future. The big challenge is successful integration. Furthermore, a library or framework for a singular concern tends to solve the concern in better ways simply because project contributors give it exclusive focus. The more I learn about a space, the more I lean towards a piece-by-piece approach.

As always, pick frameworks based on the needs at hand. For example, I like to use Django to make websites for my wife’s small businesses because the admin interface is just so convenient for her, even though I could get away with Flask. However, I’ll probably pick Mocha (piece-by-piece) over Jasmine (all-in-one) whenever I return to JavaScript testing.

One comment

  1. Not sure all in ones are better for beginners. Big, all in one frameworks can be desperately unfriendly, and massive overkill for what a beginner is trying to achieve. I made a very quick little website for my friends to do a secret santa. Flask was more than sufficient to hack together some truly awful code to get the job done. It would have taken forever to learn Django to do the same job.

    If I was going to do something professionally, I’d be looking a lot more closely at Django. But you ultimately learn piece by piece, and I think sometimes the all in ones make more sense when it’s simplifying problems you understand rather than introducing everything from scratch.

    Like

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