Right, you want to use Appsignal to monitor your Phoenix Liveview application? Here's how you do it.

Note: This guide assumes you're on Liveview 0.17.5 or newer because we depend on the new liveview event hooks.

First install the appsignal_phoenix package. Because this package already depends on the appsignal package, there's no need for you to manually add it.

defp deps do
  [
    {:appsignal_phoenix, "~> 2.0"},

Then we're going to hook into the lifecycle in two spots. One for the mount event, and one for the handle_event.

In your myproject_web.ex add two on_mount handlers.

  def live_view do
    quote do
      use Phoenix.LiveView,
        layout: {GamingWeb.LayoutView, "live.html"}

      on_mount(GamingWeb.InitAssigns)
      on_mount(GamingWeb.Appsignal)

      unquote(view_helpers())
    end
  end

Tracking mount events

Let's start by creating the InitAssigns module.

defmodule GamingWeb.InitAssigns do
  @moduledoc false
  import Phoenix.LiveView
  import Appsignal.Phoenix.LiveView, only: [live_view_action: 5]

  def on_mount(:default, params, session, socket) do
    # here's where we're calling appsignal instrumentation
    live_view_action(socket.view, "mount", params, socket, fn ->
      socket =
        socket
        |> assign_new(:current_user, fn ->
          get_user(session["user_token"])
        end)

      {:cont, socket}
    end)
  end
end

We're done, every mount will be tracked properly on Appsignal.

Tracking handle_event events

We're going to track the handle_event lifecycle event. If you want you can track others like:

defmodule GamingWeb.Appsignal do
  @moduledoc false
  import Phoenix.LiveView
  import Appsignal.Phoenix.LiveView, only: [live_view_action: 5]

  def on_mount(:default, _params, _session, socket) do
    socket =
      attach_hook(socket, :mount_hook, :handle_event, fn
        event, params, socket ->
          live_view_action(socket.view, event, params, socket, fn ->
            {:cont, socket}
          end)
      end)

    {:cont, socket}
  end
end

And we're done. Here I'm tracking a simple form event named submit.

def handle_event("submit", %{"waitlist" => params}, socket) do
  {:noreply, socket}
end