Provide metrics on root URL

2022-02-20 22:47:48 +01:00
parent 79e83afafb
commit c8a043528b
23 changed files with 869 additions and 127 deletions
--- a/lib/kafkaex_lag_exporter/prom_ex.ex
+++ b/lib/kafkaex_lag_exporter/prom_ex.ex
@@ -0,0 +1,76 @@
+defmodule KafkaexLagExporter.PromEx do
+  @moduledoc """
+  Be sure to add the following to finish setting up PromEx:
+
+  1. Update your configuration (config.exs, dev.exs, prod.exs, releases.exs, etc) to
+     configure the necessary bit of PromEx. Be sure to check out `PromEx.Config` for
+     more details regarding configuring PromEx:
+     ```
+     config :kafkaex_lag_exporter, KafkaexLagExporter.PromEx,
+       disabled: false,
+       manual_metrics_start_delay: :no_delay,
+       drop_metrics_groups: [],
+       grafana: :disabled,
+       metrics_server: :disabled
+     ```
+
+  2. Add this module to your application supervision tree. It should be one of the first
+     things that is started so that no Telemetry events are missed. For example, if PromEx
+     is started after your Repo module, you will miss Ecto's init events and the dashboards
+     will be missing some data points:
+     ```
+     def start(_type, _args) do
+       children = [
+         KafkaexLagExporter.PromEx,
+
+         ...
+       ]
+
+       ...
+     end
+     ```
+
+  3. Update your `endpoint.ex` file to expose your metrics (or configure a standalone
+     server using the `:metrics_server` config options). Be sure to put this plug before
+     your `Plug.Telemetry` entry so that you can avoid having calls to your `/metrics`
+     endpoint create their own metrics and logs which can pollute your logs/metrics given
+     that Prometheus will scrape at a regular interval and that can get noisy:
+     ```
+     defmodule KafkaexLagExporterWeb.Endpoint do
+       use Phoenix.Endpoint, otp_app: :kafkaex_lag_exporter
+
+       ...
+
+       plug PromEx.Plug, prom_ex_module: KafkaexLagExporter.PromEx
+
+       ...
+     end
+     ```
+
+  4. Update the list of plugins in the `plugins/0` function return list to reflect your
+     application's dependencies. Also update the list of dashboards that are to be uploaded
+     to Grafana in the `dashboards/0` function.
+  """
+
+  use PromEx, otp_app: :kafkaex_lag_exporter
+
+  alias PromEx.Plugins
+
+  @impl true
+  def plugins do
+    [
+      # PromEx built in plugins
+      Plugins.Application,
+      Plugins.Beam
+      # {Plugins.Phoenix, router: KafkaexLagExporterWeb.Router, endpoint: KafkaexLagExporterWeb.Endpoint},
+      # Plugins.Ecto,
+      # Plugins.Oban,
+      # Plugins.PhoenixLiveView,
+      # Plugins.Absinthe,
+      # Plugins.Broadway,
+
+      # Add your own PromEx metrics plugins
+      # KafkaexLagExporter.Users.PromExPlugin
+    ]
+  end
+end