blset
When creating a new project with
mix phx.new proj --umbrella
the phoenix_pubsub dependency is placed in the mix.exs of the proj app and not under the proj_web app.
but that seems against app isolation. since the proj app, in the idea, should have no dependency on phoenix nor any web consideration.
more over when manually placing the phoenix pub_sub in the proj_web mix.exs and adjusting the config of the umbrella config, it does not work with message
unknown registry: ProjWeb.PubSub
how to make i work with phoenix_pubsub under the web app ?
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NobbZ
PubSub, even though used by the channels, is not a web concern. It is to send (publish) messages to a couple of subscribers, in a way that the publisher does not need to know the subscribers, while also the subscribers do not need to know the publisher(s) in advance.
It can be used for a lot more things than just “web”.
blset
All right, but having both mix apps proj and proj_web under umbrella, what if I wanted to place the phoenix pub sub dependency (which is needed by proj_web --the phoenix app-- ) under the proj_web, because I don’t need pubsub in the proj app and pubsub is needed by the phoenix app ?
LostKobrakai
That should be no problem for as long as you make sure pubsub is started before the endpoint in your supervision tree.
blset
How to make that afterwards ?
there are two scenarios :
1 using mix phx.new proj --umbrella
it works out of the box but if I move the dependency to the proj_web mix.exs it does not work
anymore with the error message previously cited
2 creating a bare mix umbrella project and then mix phx.new.web --noecto --live
when the dependency is moved, the config file at the top of the umbrella project must be modified, that’s ok, but
even in scenario 1 I see no where PubSub is started in a supervision tree
LostKobrakai
You need to move both the dependency and where pubsub is started in the supervision tree (application.ex) and rename all the places where the module name is mentioned.
blset
even in a bare phoenix project Proj/ProjWeb not under an umbrella there is no place where the Proj.PubSub is explicitly started
If I try to put Proj.PubSub (the missing name in registry) in the children for the supervision tree the message is module does not exist
looks like the PubSub is hardcoded on the name Proj (if phx.new proj)
LostKobrakai
Here’s the place it’s started for a single project phoenix app:
And here for the umbrella version:
blset
thank you
so I did not have it because I used the flag --no-ecto and the pubSub goes with it in the template “if ecto”
LostKobrakai
No, there are
<% end %>parts directly on the line with the repo declaration.blset
you are right but then maybe when you use mix phx.new.web (which I did afterwards having previously created a general mix umbrella project) you do not have the PubSub started in the supervision tree