Intro to reactive programming with OL

[Charlotte-Holt]

Need a topic that talks about "here's how reactive works in Open Liberty". Introduce MicroProfile Reactive Messaging and message brokers (Kafka, specifically). Start by looking through the guides and

Contacts: Gordon Hutchison and Andrew Rouse

Resources:

• https://openliberty.io/guides/#reactive_service
• https://download.eclipse.org/microprofile/microprofile-reactive-messaging-1.0/microprofile-reactive-messaging-spec.html#_microprofile_reactive_messaging
• https://openliberty.io/blog/2019/09/13/microprofile-reactive-messaging.html

[dmuelle]

Don't prioritize until discussing with Alasdair

[dmuelle]

this will be handled in #6928