Rebooting Jasper

Jasper is a long running OSS passion project of mine. As it is now, Jasper is a command processing tool similar to Brighter or MassTransit that can be used as either an in memory mediator tool (like a superset of Mediatr) or as a service bus framework for asynchronous messaging. Jasper was originally conceived as a way to recreate the “good” parts of FubuMVC like low code ceremony, minimal intrusion of the framework into application code, and effective usage of the Russian Doll model for the execution pipeline. At the same time though, I wanted Jasper to improve upon the earlier FubuMVC architecture by maximizing performance, minimizing object allocations, easier configuration and bootstrapping, and making it much easier for developers to troubleshoot runtime issues.

I actually did cut a Jasper V1 release early in the COVID-19 pandemic, but otherwise dropped it to focus on Marten and stopped paying any attention to it. With Marten V4 is in the books, I’m going back to working on Jasper for a little bit. For right now, I’m thinking that the Jasper V2 work is something like this:

  1. Upgrading all the dependencies and targeting .Net 5/6 (basically done)
  2. Benchmarking and optimizing the core runtime internals. Sometimes the best way to improve a codebase is to step away from it for quite a bit and come back in with fresh perspectives. There’s also some significant lessons from Marten V4 that might apply to Jasper
  3. Build in Open Telemetry tracing through Jasper’s pipeline. Really all about getting me up to speed on distributed tracing.
  4. Support the AsyncAPI standard (Swagger for asynchronous messaging). I’m really interested in this, but haven’t taken much time to dive into it yet
  5. Wire compatibility with NServiceBus so a Jasper app can talk bi-directionally with an NServiceBus app
  6. Same with MassTransit. If I decide to pursue Jasper seriously, I’d have to do that to have any shot at using Jasper at work
  7. More transport options. Right now there’s a Kafka & Pulsar transport option stuck in PR purgatory from another contributor. Again, a learning opportunity.
  8. Optimize the heck out of the Rabbit MQ usage.
  9. Go over the usability of the configuration. To be honest here, I’ve less than thrilled with our MassTransit usage and the hoops you have to jump through to bend it to our will and I’d like to see if I could do better with Jasper
  10. Improve the documentation website (if I’m serious about Jasper)
  11. Play with some kind of Jasper/Azure Functions integration. No idea what that would look like, but the point is to go learn more about Azure Functions
  12. Maybe, but a low priority — I have a working version of FubuMVC style HTTP endpoints in Jasper already. With everybody all excited about the new Minimal API stuff in ASP.Net Core v6, I wouldn’t mind showing a slightly different approach

Integrating Marten and Jasper

Maybe the single biggest reason for me to play more with Jasper is to explore some deeper integration with Marten for some more complicated CQRS and event sourcing architectural problems. Jasper already has an outbox/inbox pattern implementation for Marten. Going farther, I’d like to have out of the box solutions for:

  • Event streaming from Marten to message queues using Jasper
  • An alternative to Marten’s async daemon using Kafka/Pulsar topics
  • Using Jasper to host Marten’s asynchronous projections in a way that distributes work across running nodes
  • Experimenting more with CQRS architectures using Jasper + Marten

Anyway, I’m jotting this down mostly for me, but I’m absolutely happy for any kind of feedback or maybe to see if anyone else would be interested in helping with Jasper development.


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