May 2024 Rustacean meetup

Most non-trivial applications need a robust and flexible configuration system. Such a system becomes all the more important when the same feature needs to behave differently for different users. At Juspay, we needed a configuration system with the following properties:

• First, it should be flexible, allowing teams to make changes quickly without application deployment.
• Second, it should be Safe - ensuring that the value provided for a configuration is type correct, and the rollout of such a change is staggered.

We looked around for off-the-shelf software and did not find anything that met these requirements, so we built Superposition.

Superposition is a context-based configuration management system designed to facilitate safe and flexible rollout of config changes.

This is enabled by two key components of Superposition.

• Context Aware Config (CAC) - Lets you do granular configuration based on contextual data.
• Experimentation - Lets you do A/B configuration deployment, allowing controlled rollout and rollback mechanisms.

From discussions with multiple teams, we feel our requirements for a configuration system are universal. Teams inside Juspay like Juspay Portal, Hyper SDK and Namma Yatri have started to leverage Superposition to manage their complex configuration use-cases in production.

We have open sourced Superposition recently
https://github.com/juspay/superposition

Key highlights

• Admin UI - Out of the box administration (and tools) UI for configurations and experiments
• Rich API support - every action on the platform to manage configurations / experiments is supported with an accompanying API
• Safe configuration changes - support canary testing for releasing configuration changes using experiments
• Type/Validation support - Comprehensive type support using json-schema and custom validator function support for configuration values
• Multi-tenant support - a single deployment allows multiple tenants to manage their configurations/experiments in a completely isolated manner
• Authn/Authz support - control who can make configuration/experimentation changes