Support Grafana via prom_ex

Author: joshk

config/runtime.exs

@@ -358,6 +358,18 @@ if System.get_env("SENTRY_DSN_URL") do
     before_send: {NervesHubWeb.SentryEventFilter, :filter_non_500}
 end
 
+if System.get_env("GRAFANA_HOST") do
+  config :nerves_hub, NervesHub.PromEx,
+    manual_metrics_start_delay: :no_delay,
+    grafana: [
+      host: System.get_env("GRAFANA_HOST"),
+      auth_token: System.get_env("GRAFANA_TOKEN") || raise("GRAFANA_TOKEN is required"),
+      upload_dashboards_on_start: true,
+      folder_name: "NervesHub App Dashboards",
+      annotate_app_lifecycle: true
+    ]
+end
+
 config :nerves_hub, :statsd,
   host: System.get_env("STATSD_HOST", "localhost"),
   port: String.to_integer(System.get_env("STATSD_PORT", "8125"))

lib/nerves_hub/application.ex

@@ -39,7 +39,10 @@ defmodule NervesHub.Application do
           {Oban, Application.fetch_env!(:nerves_hub, Oban)}
         ] ++
         deployments_supervisor(deploy_env()) ++
-        endpoints(deploy_env())
+        endpoints(deploy_env()) ++
+        [
+          NervesHub.PromEx
+        ]
 
     opts = [strategy: :one_for_one, name: NervesHub.Supervisor]
     Supervisor.start_link(children, opts)

lib/nerves_hub/prom_ex.ex

@@ -0,0 +1,38 @@
+defmodule NervesHub.PromEx do
+  use PromEx, otp_app: :nerves_hub
+
+  alias PromEx.Plugins
+
+  @impl true
+  def plugins do
+    [
+      # PromEx built in plugins
+      Plugins.Application,
+      Plugins.Beam,
+      {Plugins.Phoenix, router: NervesHubWeb.Router},
+      Plugins.PhoenixLiveView,
+      Plugins.Ecto,
+      Plugins.Oban
+    ]
+  end
+
+  @impl true
+  def dashboard_assigns do
+    [
+      datasource_id: "prometheus"
+    ]
+  end
+
+  @impl true
+  def dashboards do
+    [
+      # PromEx built in Grafana dashboards
+      {:prom_ex, "application.json"},
+      {:prom_ex, "beam.json"},
+      {:prom_ex, "phoenix.json"},
+      {:prom_ex, "phoenix_live_view.json"},
+      {:prom_ex, "ecto.json"},
+      {:prom_ex, "oban.json"}
+    ]
+  end
+end

lib/nerves_hub_web/device_endpoint.ex

@@ -33,6 +33,8 @@ defmodule NervesHubWeb.DeviceEndpoint do
 
   plug(NervesHubWeb.Plugs.ImAlive)
 
+  plug(PromEx.Plug, prom_ex_module: NervesHub.PromEx)
+
   plug(Sentry.PlugContext)
 
   plug(NervesHubWeb.Plugs.Logger)

lib/nerves_hub_web/endpoint.ex

@@ -60,6 +60,8 @@ defmodule NervesHubWeb.Endpoint do
     cookie_key: "request_logger"
   )
 
+  plug(PromEx.Plug, prom_ex_module: NervesHub.PromEx)
+
   plug(Plug.RequestId)
   plug(Plug.Telemetry, event_prefix: [:phoenix, :endpoint])
   plug(NervesHubWeb.Plugs.Logger)

mix.exs

@@ -95,16 +95,17 @@ defmodule NervesHub.MixProject do
       {:phoenix_pubsub, "~> 2.0"},
       {:phoenix_swoosh, "~> 1.0"},
       {:phoenix_view, "~> 2.0"},
-      {:phoenix_test, "~> 0.3.0", only: :test, runtime: false},
+      {:phoenix_test, "0.3.1", only: :test, runtime: false},
       {:plug, "~> 1.7"},
       {:postgrex, "~> 0.14"},
+      {:prom_ex, "~> 1.10"},
       {:scrivener_ecto, "~> 2.7"},
       {:scrivener_html, git: "https://github.com/nerves-hub/scrivener_html", branch: "phx-1.5"},
       {:sentry, "~> 10.0"},
       {:slipstream, "~> 1.0", only: [:test, :dev]},
       {:sweet_xml, "~> 0.6"},
       {:swoosh, "~> 1.12"},
-      {:telemetry_metrics, "~> 0.4"},
+      {:telemetry_metrics, "~> 1.0"},
       {:telemetry_metrics_statsd, "~> 0.7.0"},
       {:telemetry_poller, "~> 1.0"},
       {:timex, "~> 3.1"},