BIW15: Python in the Cloud: Django and Flaks
- 1. Baltimore Innovation Week 2015 Python in the Cloud: Django vs Flask Alex Viana (@AlexVianaPro) Terbium Labs (@TerbiumLabs) and
- 2. Terbium Labs ❖ Terbium Labs is a Baltimore-based data intelligence company. Our product, Matchlight, allows customers to monitor the dark web for stolen data. ❖ Matchlight is primarily written in Python, running on AWS.
- 3. Motivation ❖ Django and Flask are the two most popular Python web frameworks. ❖ We use both frameworks to fill different roles in our work at Terbium Labs. ❖ It was surprisingly difficult to come to a firm decision that this was the right direction. ❖ This talk is about what we learned in the process and how it informed our decision.
- 4. Flask ❖ Flask is what the majority of our services runs on. ❖ Flask is a bare-bones Python web “microframework”. ❖ It’s great for building lightweight apps or “microservices”. ❖ How lightweight? How Mirco?
- 5. Flask is Light “Flask will never have a database layer. It will not have a form library or anything else in that direction. Flask itself just bridges to Werkzeug to implement a proper WSGI application and to Jinja2 to handle templating. It also binds to a few common standard library packages such as logging. Everything else is up for extensions.” - Flask Documentation http://flask.pocoo.org/docs/0.10/design/#what-flask-is-what- flask-is-not
- 6. Flask’s Hello World from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World!" if __name__ == "__main__": app.run()
- 7. Your Library as a Flask App from flask import Flask from my_module import important_function app = Flask(__name__) @app.route("/") def hello(): results = important_function() return results if __name__ == "__main__": app.run()
- 8. Flask in a Startup ❖ Don’t have to wrap your head around any new framework patterns. ❖ Spend most of your time writing business logic not app logic. ❖ Flask is excellent for the low-overhead rapid implementation requirements start up development.
- 9. Issues with Flask ❖ On some of our larger REST API’s things got tricky. ❖ Lots of design considerations with side effects. ❖ Development was slowing down. ❖ Maybe Flask was the wrong choice? So we looked to Django.
- 10. Django ❖ Django is far and away the most used Python web framework. ❖ It’s the “batteries included” option: database ORM, forms, admin interface, etc. ❖ But this means stopping everything and learning a new framework. How do we know this is the right choice?
- 11. Python vs Django ❖ A little Googling on the internet give you something like this: ❖ Django is for more full-featured applications. ❖ Flask is for more simple apps and rapid prototyping. ❖ Easy! But our product is made up of REST-ful micro services, shouldn’t Flask be perfect?
- 12. More Confusion ❖ Flask is deployed at LinkedIn, Pinterest, Twillio, and the 2012 Obama election campaign. That’s big stuff! ❖ Miguel Grinberg’s Flask book builds a blog app with data migrations, unit tests, authentication, etc. Those are a lot of features! ❖ On the other hand we have the Django REST Framework. REST is pretty lean, right? ❖ So who’s right? How do we choose? The clock is ticking…
- 13. Enter Django REST Framework ❖ So we gave Django REST framework a try. ❖ Django REST seemed like a contradiction at first; Django just seemed too heavy for an API. ❖ But, we realized there is a -lot- that goes into a REST API: authentication, serialization, permissions, data model, queries, testing, pagination, … ❖ Then we had our breakthrough…
- 14. Flask and Django ❖ Think of Flask as a web framework framework! ❖ Put another way, Flask is not your framework. You use Flask to build your framework. ❖ Development was slowing down because we weren’t building our product, we were building our framework.
- 15. Flask as a Framework Framework ❖ In the “Hello World” case this is trivial, all you need is in Flask, basically just a WSGI server. ❖ As you scale up you end up having to implement everything yourself, a-la the Flask book. ❖ Once you deviate from that - you’re on your own. ❖ Which can be great! Unless it’s not.
- 16. Where Flask is Great ❖ This is why The Flask book is so great; it lays out all the decisions for you. ❖ And this is why major projects can be written in Flask at companies with deep resource and experience pools. ❖ And small project are a breeze because there’s literally nothing else in the framework to think about. ❖ And this why everything in-between is so tough.
- 17. Building a Framework ❖ Is hard … just an FYI. ❖ Requires significant developer time. ❖ More importantly it requires informed opinions about how your framework should work. ❖ Even beyond that it requires knowledge about what decisions have to be made and how they interact.
- 18. Final Remarks ❖ The driver for improving our technology stack was a sense we were working against, not with our tools. Don’t ignore that, it’s a clue something is wrong. ❖ Once we realized the pain points and benefits of both systems we could confidently select different tools for different jobs. Don’t underestimate the impact of this. ❖ Both are great projects, we’re indebted to both teams.
- 19. Thank you for your attention. Questions?