Status Updates From Reactive Design Patterns

Finished… final read through the last Appendix is a copy of the Reactive Manifesto. No doubt there are parts of it that I have a greater understanding and appreciation for now, having read this book. Want to spend some more time and play with the source code samples more.

Final patterns covered are Event Sourcing and the Event Stream. The Event Sourcing pattern notes the point I noticed myself earlier in the chapter about the Events being outside of the Domain Object, but at this point notes that the Events do belong within the domain, bringing me to a content state. One consideration not mentioned here is whether to expose your internal events externally or not.

The Domain Object pattern presented is interesting. The events here are emitted by the encapsulating actor, rather than from within the domain object itself - so, akin to a response, which I tend to think is different to an event. But this is a detail; the pattern itself I like a lot.
Then, there was an intro to the Sharding pattern. Example code is a little tricky but one gets the picture.

The Throttle pattern covered; gonna study the code in more detail. Next is the Domain Object pattern, something that appeals to me as a DDD person, but was interested to read another reactive book where the authors suggested keeping domain logic directly in the actor code. The Domain Object pattern is attractive to me, from a testing perspective, so the design seems “nicer” this way.

The Drop pattern - interesting stuff about what you can do when your system is pushed to its limits

The Pull flow control pattern - great explanation. Then Managed Queue pattern now, but sleepiness strikes…

Saga, Business Handshake patterns. A few short chapters to go, the remainder looks interesting!

Forward Flow (nice) and Aggregator patterns covered. Had not though of Forward Flow before but nice concept explained very simply here. Also can be related back to resource management patterns too.

This section covered the Ask pattern. The code examples use an older version of Akka Typed API, which was unfamiliar to me but I could get the gist. Yes, this Ask pattern is nice! Great reference to Gul Agha’s work here too.

Back to easier stuff in this chapter, with Request-Response and the Self-contained message patterns covered first

End of the chapter on resource management patterns, the last one covering managed blocking.

That was the complex command pattern… which I will remember as variations of a map/reduce style big data requirement within one’s system. Never had such a requirement to handle myself to date, but will file this away in my memory…

The Complex Command pattern described here looks the same as map/reduce, but the discussion includes different approaches to passing the behavior logic to the worker nodes.

The Resource Loan pattern covered here.

The Resource Encapsulation pattern covered first in this chapter. Shows examples using the AWS EC2 client APIs, which is interesting. At least I haven’t had the chance to programmatically work with it before.

Chapter 13 on replication patterns is interesting but unfortunately quite a slog to read through, as was warned at the start of the chapter.

This chapter is tough reading at night when I am already tired and sleepy…

This section of the book has been hard to get through - it really needs solid hours of devotion to focused reading and studying the source code, which are hours I haven’t had. The chapter warned as much, though.

Multiple master patterns under discussion. I must get back to reading that Cassandra book to recall how it handles read repair…

Phew this chapter had a warning that this stuff gets pretty detailed and indeed it is tough reading… need more than one sitting to get through the active-passive pattern