The Python Podcast.__init__

The Python Podcast.__init__

The podcast about Python and the people who make it great

27 April 2021

Extensible Open Source Authorization For Your Applications With Oso - E312

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Any project that is used by more than one person will eventually need to handle permissions for each of those users. It is certainly possible to write that logic yourself, but you’ll almost certainly do it wrong at least once. Rather than waste your time fighting with bugs in your authorization code it makes sense to use a well-maintained library that has already made and fixed all of the mistakes so that you don’t have to. In this episode Sam Scott shares the Oso framework to give you a clean separation between your authorization policies and your application code. He explains how you can call a simple function to ask if something is allowed, and then manage the complex rules that match your particular needs as a separate concern. He describes the motivation for building a domain specific language based on logic programming for policy definitions, how it integrates with the host language (such as Python), and how you can start using it in your own applications today. This is a must listen even if you never use the project because it is a great exploration of all of the incidental complexity that is involved in permissions management.


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  • Your host as usual is Tobias Macey and today I’m interviewing Sam Scott about Oso, an open source library for managing authorization in your applications


  • Introductions
  • How did you get introduced to Python?
  • Can you start by describing what Oso is and the story behind it?
  • What was missing from the ecosystem of authorization libraries/frameworks that motivated you to create a new one?
  • What are some of the most common mistakes that you see developers make when implementing authorization logic?
  • At a high level, what is the process of using Oso to add access control policies to a piece of software?
  • What is the motivation for using a DSL for defining policies as opposed to writing those definitions in pure Python?
    • How have you approached the design of the policy language, particularly deciding what constraints to impose?
    • What other policy frameworks or dialects have you drawn inspiration from?
  • How is the Oso framework implemented?
    • How have the goals and design of Oso changed or evolved since you first began working on it?
  • What are some useful design patterns for integrating Oso into an application?
    • How does the type of application (e.g. web app vs. system daemon, etc.) affect the ways that Oso is used?
  • Given that Oso supports multiple language runtimes, what is involved in defining and enforcing policies that span multiple processes? (e.g. Python backend and Javascript frontend, Python microservice communicating with Go microservice, etc.)
  • What are some of the common mistakes or areas of confusion for users who are getting started with Oso and Polar?
  • What are some of the capabilities of Oso that are often overlooked or misunderstood?
  • I noticed that you’re backed by some venture firms. What is your current product vision and how does that relate to your current open source goals?
  • What are some of the most interesting, innovative, or unexpected ways that you have seen Oso used?
  • What are some of the most interesting, unexpected, or challenging lessons that you have learned while working on and with oso?
  • When is Oso the wrong choice?
  • What do you have planned for the future of the project?

Keep In Touch


Closing Announcements

  • Thank you for listening! Don’t forget to check out our other show, the Data Engineering Podcast for the latest on modern data management.
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The intro and outro music is from Requiem for a Fish The Freak Fandango Orchestra / CC BY-SA

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