Part 1: Adding custom metrics to a Phoenix 1.5 live dashboard
The code for this demo is available here
As I mentioned in the previous post, one of the downsides to the new Phoenix live dashboard is that the metrics and graphs are transient. In order to see longer term trends, we’re going to send our telemetry metrics to InfluxDB via StatsD.
Add the statsd reporter to your Phoenix app
Open lib/metrics_demo_web/telemetry.ex and add the following line to the deps:
{:telemetry_metrics_statsd, "~> 0.4"},It should now look like this:
defp deps do
[
{:phoenix, "~> 1.5.3"},
{:phoenix_ecto, "~> 4.1"},
{:ecto_sql, "~> 3.4"},
{:postgrex, ">= 0.0.0"},
{:phoenix_live_view, "~> 0.13.0"},
{:floki, ">= 0.0.0", only: :test},
{:phoenix_html, "~> 2.11"},
{:phoenix_live_reload, "~> 1.2", only: :dev},
{:phoenix_live_dashboard, "~> 0.2.0"},
{:telemetry_metrics, "~> 0.4"}, …Part 2: Sending Phoenix 1.5 metrics to InfluxDb
The code for this demo is available here
To get started, make sure you have the Phoenix 1.5 project generator:
mix archive.uninstall phx_new
mix archive.install hex phx_new 1.5.1Create a new Phoenix 1.5 project:
mix phx.new metrics_demo
cd metrics_demo && mix ecto.createOpen metrics_demo/lib/metrics_demo_web/controllers/page_controller.ex and add the following line to emit a telemetry event:
:telemetry.execute([:metrics_demo, :render], %{controller: "PageController", action: "index"})It should now look like this:
defmodule MetricsDemoWeb.PageController do
use MetricsDemoWeb, :controller
def index(conn, _params) do
:telemetry.execute([:metrics_demo, :render], %{controller: "PageController", action: "index"})
render(conn, "index.html")
end
endNow open metrics_demo/lib/metrics_demo_web/telemetry.ex …
The Heroku buildpacks make some assumptions about your project based on earlier versions, but with a few tweaks can be used with version 1.4 of Elixir and 1.3 of Phoenix.
This assumes you created your project with mix phx.new hello_phoenix --umbrella. Replace hello_phoenix and HelloPhoenix with your app name where appropriate.
Most of the instructions at http://www.phoenixframework.org/docs/heroku are still valid. Complete those and then make the following changes:
- This may be obvious, but the
config/prod.exsmentioned is the one in the web app folder:hello_phoenix_umbrella/apps/hello_phoenix_web/config/prod.exs. - Change the reference in
prod.exsfromHelloPhoenix.EndpointtoHelloPhoenix.Web.Endpoint. - You’ll also need to remove
import_config "prod.secret.exs"fromhello_phoenix_umbrella/config/prod.exs. …
