OeditusCredo.Check.Warning.MissingTelemetryInLiveViewMount (OeditusCredo v0.6.3)

Basics

This check has a base priority of normal and works with any version of Elixir.

Explanation

LiveView mount/3 callbacks should emit telemetry events for observability.

Instrumenting LiveView mounts helps track which LiveViews are being accessed, how long they take to initialize, and can help identify performance bottlenecks.

Bad:

defmodule MyAppWeb.DashboardLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    data = load_expensive_data()
    {:ok, assign(socket, data: data)}
  end
end

Good:

defmodule MyAppWeb.DashboardLive do
  use MyAppWeb, :live_view

  def mount(_params, _session, socket) do
    :telemetry.execute(
      [:phoenix, :live_view, :mount],
      %{system_time: System.system_time()},
      %{module: __MODULE__}
    )
    data = load_expensive_data()
    {:ok, assign(socket, data: data)}
  end
end

Check-Specific Parameters

Use the following parameters to configure this check:

:exclude_test_files

Set to true to skip test files (default: false)

This parameter defaults to nil.

General Parameters

Like with all checks, general params can be applied.

Parameters can be configured via the .credo.exs config file.