DynamicSupervisor and GenServer usage

[jhefreyzz]

I’m learning Phoenix and OTP by making a simple game. I’ve asked somewhat related to this topic but it’s not really yet clear to me the usage of DynamicSupervisor and GenServer.

My app index page is a LiveView page which displays all the games (Standy, Started, Ended). It also has a button which would create another game. Now new game is created, DynamicSupervisor starts a child with a named Genserver using Registry and via_tuple.

When a particle route together with its id as route param is clicked on the home page, I can then easily calls rhat specific GenServer and manipulate states when the game started or ended.

So far what I’ve understood is in order for me to display all I think I need to know the processes under the supervisor (maybe I need supervisors which_children) and access their own state. I dont know how to access the states of the supervisor children.

My analogy regarding GenServer and DynamicSupervisor when applied to my game requirements.

DynamicSupervisor spawns
Game 1 (GenServer)
Game 2 (GenServer)
Game 3 (GenServer)

Please correct if I’m wrong. Sorry for the noob question.
If there are things to clarify, please let me know.

Thank you.

[OvermindDL1]

@jhefreyzz

My app index page is a LiveView page which displays all the games (Standy, Started, Ended). It also has a button which would create another game. Now new game is created, DynamicSupervisor starts a child with a named Genserver using Registry and via_tuple.

Sounds good.

@jhefreyzz

When a particle route together with its id as route param is clicked on the home page, I can then easily calls rhat specific GenServer and manipulate states when the game started or ended.

Yep yep.

@jhefreyzz

So far what I’ve understood is in order for me to display all I think I need to know the processes under the supervisor (maybe I need supervisors which_children) and access their own state. I dont know how to access the states of the supervisor children.

I would store their name<->pid mappings somewhere else, probably Registry or ETS or so, have them add themselves to it when created and remove themselves when stored (Registry makes this much easier and reliable).

[jhefreyzz]

May I know how would I implement this one. I’m not sure how.

[OvermindDL1]

I’d say look at the Registry docs, basically just when you create a new child then have that child register itself into the Registry, then you can look it back up from the registry or get a full listing or so.