Embedding in your app

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Add the dependency:

# mix.exs
defp deps do
  [{:pusher_server, "~> 0.1"}]
end

Start it from your supervision tree:

# lib/my_app/application.ex
children = [
  MyApp.Repo,
  MyAppWeb.Endpoint,
  {PusherServer,
   name: MyApp.PusherServer,
   port: 6001,
   app_key: System.fetch_env!("PUSHER_APP_KEY"),
   app_secret: System.fetch_env!("PUSHER_APP_SECRET"),
   app_id: System.fetch_env!("PUSHER_APP_ID")}
]

Nothing starts automatically when the package is a dependency. Only the standalone release (this repository's own config/runtime.exs) turns on auto-start; a dependency's config files are ignored by the host app.

It runs its own listener

PusherServer starts its own Cowboy listener on its own :port. It is not a Plug you mount in your Phoenix router or endpoint. Your frontend connects to that port (directly or through your proxy), and your backend sends events to the same port over the REST API.

Several instances

Each instance needs a unique :name and its own :port, and keeps fully separate channel and presence state:

children = [
  {PusherServer, name: MyApp.PusherA, port: 6001, app_id: "a", app_key: "ka", app_secret: "sa"},
  {PusherServer, name: MyApp.PusherB, port: 6002, app_id: "b", app_key: "kb", app_secret: "sb"}
]

Sending events from Elixir

Events are sent the same way as for any Pusher server: a signed POST /apps/:app_id/events. Any Pusher HTTP client library works, pointed at your host and port.

Draining on shutdown

When the standalone release stops, it drains automatically. If you embed and want clients to reconnect cleanly before your app exits, call PusherServer.drain/1 from your application's prep_stop/1:

@impl true
def prep_stop(state) do
  PusherServer.drain(MyApp.PusherServer)
  Process.sleep(1_000)
  state
end

It must run in prep_stop/1, not stop/1: by stop/1 the supervision tree is already gone and the sockets are already closed.

Redis

Pass redis_url: "redis://..." to share state between several nodes. See Multi-server.