Thread by @UdiDahan

I've been asked my thoughts about Netflix Conductor - a microservices orchestrator: medium.com/netflix-techbl…

This is probably connected to my earlier thread recommending against orchestration as an approach for complex business systems:

https://twitter.com/UdiDahan/status/1087451545636126720

The main thing I'd like to note from the Netflix Conductor article is this:

So, yes, I do agree that trying to use pub/sub for everything is a bad idea.
That would be true of any pattern.

Patterns are, after all, a solution for a *given* context.

Complex systems often have many contexts in them, thus justifying the use of multiple patterns.

On the topic of Tight Coupling resulting from the use of pub/sub - well, as many people have said before, if you share a domain model or database across pub/sub boundaries, then you're still tightly coupled. Pub/sub won't help much.

Alternatively, passing all the data through pub/sub events and removing the shared database connection won't really help much either. It's the same logical data coupling whether it's pushed or pulled.

This is where UI / View Model Composition techniques help.

Each logical service can truly own its data, top to bottom, composing that into all the necessary places it needs to be shown - not needing to share it with other logical services.

This reduces the logical coupling.

For more info on how to do UI / View Model Composition, see our self-paced online workshop, specifically the first exercise:

github.com/Particular/Wor…

Now, onto the 3rd point raised in the article:

All that loose coupling makes it hard to see the state of things.

This is where having proper tracing that threads across all calls is important. Luckily, there are published patterns for that:

enterpriseintegrationpatterns.com/ramblings/09_c…

By making sure appropriate correlation and conversation ID headers are propagated across these loosely-coupled interactions, and then auditing all of those flows, we can generate visualizations showing the state of things like this:

docs.particular.net/serviceinsight…

Gotta run. Will continue this thread a bit later.