defmodule NotesAppWeb.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 will execute the given period measurements # every 10_000ms. Learn more here: https://hexdocs.pm/telemetry_metrics {:telemetry_poller, measurements: periodic_measurements(), period: 10_000} # Add reporters as children of your supervision tree. # {Telemetry.Metrics.ConsoleReporter, metrics: metrics()} ] Supervisor.init(children, strategy: :one_for_one) end def metrics do [ # Phoenix Metrics summary("phoenix.endpoint.start.system_time", unit: {:native, :millisecond} ), summary("phoenix.endpoint.stop.duration", unit: {:native, :millisecond} ), summary("phoenix.router_dispatch.start.system_time", tags: [:route], unit: {:native, :millisecond} ), summary("phoenix.router_dispatch.exception.duration", tags: [:route], unit: {:native, :millisecond} ), summary("phoenix.router_dispatch.stop.duration", tags: [:route], unit: {:native, :millisecond} ), summary("phoenix.socket_connected.duration", unit: {:native, :millisecond} ), summary("phoenix.channel_joined.duration", unit: {:native, :millisecond} ), summary("phoenix.channel_handled_in.duration", tags: [:event], unit: {:native, :millisecond} ), # Database Metrics summary("notes_app.repo.query.total_time", unit: {:native, :millisecond}, description: "The sum of the other measurements" ), summary("notes_app.repo.query.decode_time", unit: {:native, :millisecond}, description: "The time spent decoding the data received from the database" ), summary("notes_app.repo.query.query_time", unit: {:native, :millisecond}, description: "The time spent executing the query" ), summary("notes_app.repo.query.queue_time", unit: {:native, :millisecond}, description: "The time spent waiting for a database connection" ), summary("notes_app.repo.query.idle_time", unit: {:native, :millisecond}, description: "The time the connection spent waiting before being checked out for the query" ), # VM Metrics summary("vm.memory.total", unit: {:byte, :kilobyte}), summary("vm.total_run_queue_lengths.total"), summary("vm.total_run_queue_lengths.cpu"), summary("vm.total_run_queue_lengths.io") ] end defp periodic_measurements do [ # A module, function and arguments to be invoked periodically. # This function must call :telemetry.execute/3 and a metric must be added above. # {NotesAppWeb, :count_users, []} ] end end