TelemetryMetricsTelegraf

InfluxDB reporter for Telemetry.Metrics. The core idea of this implementation is to avoid any in-memory aggregation and let telegraf do the heavy lifting.

Installation

The package can be installed by adding telemetry_metrics_telegraf to your list of dependencies in mix.exs:

def deps do
  [
    {:telemetry_metrics_telegraf, "~> 0.3.0"}
  ]
end

See documentation at hexdocs.pm.

Quickstart guide

Consider we have a freshly generated phoenix app with telemetry module and we want to use instream as our telegraf client.

Add telemetry_metrics_telegraf to the app telemetry supervision tree

defmodule MyAppWeb.Telemetry do
  import Telemetry.Metrics

  def init(_arg) do
    children = [
      {:telemetry_poller, measurements: periodic_measurements(), period: 10_000},
      [
        {TelemetryMetricsTelegraf,
         metrics: metrics(),
         adapter:
           {TelemetryMetricsTelegraf.Adapters.Instream, [connection: MyApp.InstreamConnection]}}
      ]
    ]

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

  def metrics do
    [
      # Phoenix Metrics
      summary("phoenix.endpoint.stop.duration"),

      # Database Metrics
      summary("my_app.repo.query.total_time", unit: {:native, :millisecond}, tags: [:source]),
      summary("my_app.repo.query.decode_time", unit: {:native, :millisecond}, tags: [:source]),
      summary("my_app.repo.query.query_time", unit: {:native, :millisecond}, tags: [:source]),
      summary("my_app.repo.query.queue_time", unit: {:native, :millisecond}, tags: [:source]),
      summary("my_app.repo.query.idle_time", unit: {:native, :millisecond}, tags: [:source]),

      # 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
    []
  end
end

The configuration above emits following influxdb measurements on corresponding telemetry events

phoenix.endpoint.stop duration=42
my_app.repo.query,source="users" total_time=10,decode_time=1,query_time=2,
queue_time=3,idle_time=4
vm.memory total=100
vm.total_run_queue_lengths total=42,cpu=40,io=2

On startup telegraf reporter will log something like:

[info]  Suggested telegraf aggregator config for your metrics:
[[aggregators.basicstats]]
period = "30s"
drop_original = true
namepass = ["my_app.repo.query", "phoenix.endpoint.stop", "vm.memory", "vm.total_run_queue_lengths"]

or you can render telegraf config manually by calling

config_string = TelemetryConfigTelegraf.Telegraf.ConfigAdviser.render(MyAppWeb.Telemetry.metrics(), options_kw)

Copy/paste aggregators config into your telegraf configuration file and you're good to go.