Hey, let’s say I have a DynamicSupervisor and I want to start children on it. The children itself consist of a Supervisor with a few children on it, which act like one unit under the DynamicSupervisor. Something like this: DynamicSupervisor -- Supervisor ------ Main ------ Worker_1 ------ Worker_…

So, I played around a bit and created an example add. I used a single Registry which seems to work fine. Code can be found here: https://github.com/PhillippOhlandt/dynamic_supervision_communication For now, I just added the mechanism to start a new unit which then starts a service and two worker …

I already had the idea of one Registry per “unit” in mind but were stuck at the point of discovering that registry process. Your idea sounds quite doable. I need to tinker around a bit and see how it turns out with actual code.

You don’t need a registry per unit if you register the processes with tuples, like {:unit_supervisor, unit_id}, {:unit_worker, 1, unit_id}, etc. If your units don’t have a unique id already you can generate one (make_ref) in the supervisor’s init callback and pass it down as an argument to the chil…

I actually would like to have one Registry per unit. If something bad happens with the Registry, it won’t affect the other units.

That would kind of defeat the role of Registry, to have one place where to lookup processes by key… But nothing forbids You to monitor others processes from Main, with a private ETS table, for example. This way Main would be used as a small registry too. You would catch EXIT, and adjust your ETS en…

I already had cases where the GenServers that were monitored by my single Registry blew up the Registry due to fast restarting or whatever. Then everything went down. That’s why I like to have many Registries.

You still can, but what You need is a Registry of Registries :slight_smile:

It should be perfectly enough to have one registry for the entire application. It’s performant enough.

@michalmuskala I am not saying it’s not performant enough. I just had problems with it in the past that the Registry crashed for some reasons.

[image] Phillipp: I already had cases where the GenServers that were monitored by my single Registry blew up the Registry due to fast restarting or whatever. Are you sure the supervisor of the registry didn’t crash, bringing down the registry together with it? If you don’t trust Registry, yo…

I can’t tell what happened exactly. The setup in that project is like this: Supervisor: -- Registry -- DynamicSupervisor ------ DynamicSupervisor ---------- GenServer ---------- GenServer ---------- GenServer ------ DynamicSupervisor ---------- GenServer ---------- GenServer ---------- GenServer .…

Process communication in a dynamic supervision setup

Questions & Help Questions

kokolegorille July 11, 2018, 11:02am 9

You still can, but what You need is a Registry of Registries