feat: add beam-dashboards integration (#902)

Author: MegaRedHand

lib/beacon_api/endpoint.ex

@@ -8,6 +8,7 @@ defmodule BeaconApi.Endpoint do
     json_decoder: Phoenix.json_library()
   )
 
+  plug(BeaconApi.MetricsExporter)
   plug(BeaconApi.Router)
   plug(Sentry.PlugContext)
 end

lib/beacon_api/metrics_exporter.ex

@@ -0,0 +1,4 @@
+defmodule BeaconApi.MetricsExporter do
+  @moduledoc false
+  use Prometheus.PlugExporter
+end

lib/lambda_ethereum_consensus/application.ex

@@ -8,6 +8,7 @@ defmodule LambdaEthereumConsensus.Application do
 
   @impl true
   def start(_type, _args) do
+    BeaconApi.MetricsExporter.setup()
     # Configure sentry logger handler
     Logger.add_handlers(:lambda_ethereum_consensus)
     mode = get_operation_mode()