Thank you! Excellent post. Just a note: prometheus_plugs can also instrument a single plug or it’s own pipeline:
defmodule EnsureAuthenticatedInstrumenter do
use Prometheus.PlugInstrumenter
plug Guardian.Plug.EnsureAuthenticated
def label_value(:authenticated, {conn, _}) do
conn.status != 401
end
end
Basically it uses Plug.Builder and similar to it in this aspect.
