Optional Telemetry.Metrics definitions for Rheo (v0.10+ / ADR 027).

Requires {:telemetry_metrics, "~> 1.0"} (or compatible) in the host app. Wire into LiveDashboard, PromEx, or any reporter that accepts metric specs.

These are counters / summaries over existing [:rheo, …] events — they do not change settle semantics. Alert thresholds stay in the host.

Host wiring

Append metrics/0 to your app's metric list (Phoenix Telemetry module, PromEx plugin, or a custom reporter):

defmodule MyAppWeb.Telemetry do
  use Supervisor
  import Telemetry.Metrics

  def start_link(arg) do
    Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
  end

  @impl true
  def init(_arg) do
    children = [
      {:telemetry_poller, measurements: [], period: 10_000}
    ]

    Supervisor.init(children, strategy: :one_for_one)
  end

  def metrics do
    [
      # … host metrics …
    ] ++ Rheo.Telemetry.Metrics.metrics()
  end
end

LiveDashboard (when the reporter uses that module):

live_dashboard "/dashboard",
  metrics: MyAppWeb.Telemetry,
  additional_pages: [rheo: Rheo.LiveDashboard.Page]

See Rheo.Telemetry for the underlying event names.