Real-time Flag Updates Beyond Kubernetes

[beeme1mr]

Problem

Flagd supports various sync options include watching a local file, HTTP polling, and subscribing to the Kubernetes API. In most configurations, the Kubernetes API is the only option that currently supports near real-time flag configuration updates. This introduces some challenges in Kubernetes clusters that do not allow direct access to the API and environments that are not using Kubernetes at all. A more flexible sync option that supports real-time flag updates would help overcome these challenges.

Requirements

• Flag changes are reflected in near real-time in flagd
• The new real-time flagd sync does not rely on the Kubernetes API
• More robust testing of TLS support in CI

Next steps

• Real-time Flag Update via gRPC in Kubernetes

[beeme1mr]

This solution may resolve open-feature/open-feature-operator#250

[AlexsJones]

Perhaps this should be an OFEP?

[beeme1mr]

@AlexsJones sure, we can start there. This was meant to be more of an epic level problem statement. Unfortunately, GitHub requires all issues to be associated with a repo even if they're higher level.

My initial thought is that we could add a gRPC sync that would theoretically solve all the problems listed above but I'm open to suggestions. Starting with an OFEP would be a good place to start.

[Kavindu-Dodan]

I will start a POC with gRPC and see how this fits to flagd. Throught POC I will see,

• Refactoring of current sync methods
• gRPC sync method & limitations
• OFEP and Approval
• Basic implementation
• Security considerations & Options

[Kavindu-Dodan]

General refactoring of flag update providers (isync impls) - #291

[Kavindu-Dodan]

OFEP is ready [1] along with POC [2]

[1] - open-feature/ofep#45
[2] - #297

[ekkinox]

I'm really eager to be able to test this.
Making flagd fed from grpc streams is imo one of the best move that could be done (great flexibility + ~ instant updates)