Replace custom admin dashboard with phoenix_live_dashboard

README.md

@@ -27,7 +27,7 @@ that I'd like to improve.
 
 ### Admin area
 
-There is a minimal admin page where you can see some stats about current lassos on [/admin](http://localhost:4000/admin). This page is protected by basic auth, the credentials can be configured in `config.exs`. By default the password is read from the environment variable `ADMIN_PASSWORD`.
+There's a Phoenix Live Dashboard available on [/admin](http://localhost:4000/admin). This page is protected by basic auth, the credentials can be configured in `config.exs`. By default the password is read from the environment variable `ADMIN_PASSWORD`.
 
 ## Building a release
 

lib/lasso.ex

@@ -7,11 +7,6 @@ defmodule Lasso do
   @cache_id Application.get_env(:lasso, Lasso)[:cache_name]
   @request_limit Application.get_env(:lasso, Lasso)[:max_requests_per_lasso]
 
-  @active_lassos_key :active_lassos
-  @total_lassos_key :total_lassos
-
-  @admin_events Application.get_env(:lasso, Lasso)[:admin_events_topic]
-
   @topic inspect(__MODULE__)
 
   def subscribe(uuid) do
@@ -21,47 +16,40 @@ defmodule Lasso do
   @doc """
   Create a new lasso that we need to keep track of
   """
-  def create(uuid, opts \\ [update_stats: true]) do
-    result = ConCache.put(@cache_id, uuid, [])
-    if opts[:update_stats], do: update_stats()
-    result
-  end
-
-  defp update_stats() do
-    ConCache.update(@cache_id, @active_lassos_key, fn val ->
-      case val do
-        nil -> {:ok, 1}
-        val -> {:ok, val + 1}
-      end
-    end)
-
-    ConCache.update(@cache_id, @total_lassos_key, fn val ->
-      case val do
-        nil -> {:ok, 1}
-        val -> {:ok, val + 1}
-      end
-    end)
-
-    notify_stats()
+  def create(uuid, _opts \\ [update_stats: true]) do
+    with_telemetry_events(
+      fn -> ConCache.put(@cache_id, uuid, []) end,
+      {:action, %{action: :create}}
+    )
   end
 
   @doc """
   Get all the requests for a lasso
   """
   def get(uuid) do
-    case ConCache.get(@cache_id, uuid) do
-      nil -> {:error, :no_such_key, uuid}
-      value -> {:ok, value}
-    end
+    with_telemetry_events(
+      fn ->
+        case ConCache.get(@cache_id, uuid) do
+          nil -> {:error, :no_such_key, uuid}
+          value -> {:ok, value}
+        end
+      end,
+      {:action, %{action: :get}}
+    )
   end
 
   @doc """
   Append a request to a lasso
   """
   def add(uuid, request) do
-    with :ok <- update(uuid, request) do
-      notify_subscribers(uuid, {:request, request})
-    end
+    with_telemetry_events(
+      fn ->
+        with :ok <- update(uuid, request) do
+          notify_subscribers(uuid, {:request, request})
+        end
+      end,
+      {:request, %{request: request}}
+    )
   end
 
   defp notify_subscribers(uuid, data) do
@@ -72,18 +60,28 @@ defmodule Lasso do
   Delete a lasso
   """
   def delete(uuid) do
-    ConCache.delete(@cache_id, uuid)
-    notify_subscribers(uuid, :delete)
+    with_telemetry_events(
+      fn ->
+        ConCache.delete(@cache_id, uuid)
+        notify_subscribers(uuid, :delete)
+      end,
+      {:action, %{action: :delete}}
+    )
   end
 
   @doc """
   Clear all requests for a lasso
   """
   def clear(uuid) do
-    with {:ok, _} <- get(uuid),
-         :ok <- create(uuid, update_stats: false) do
-      notify_subscribers(uuid, :clear)
-    end
+    with_telemetry_events(
+      fn ->
+        with {:ok, _} <- get(uuid),
+             :ok <- create(uuid, update_stats: false) do
+          notify_subscribers(uuid, :clear)
+        end
+      end,
+      {:action, %{action: :clear}}
+    )
   end
 
   @doc """
@@ -92,29 +90,8 @@ defmodule Lasso do
   def cache_callback({:update, _cache_pid, _key, _value}), do: :ok
 
   def cache_callback({:delete, _cache_pid, _key}) do
-    ConCache.update(@cache_id, @active_lassos_key, fn val ->
-      case val do
-        nil -> {:ok, 0}
-        val -> {:ok, max(0, val - 1)}
-      end
-    end)
-
-    notify_stats()
-  end
-
-  @doc """
-  Get statistics about lassos
-  """
-  def stats() do
-    active_lassos = ConCache.get(@cache_id, @active_lassos_key) || 0
-    total_lassos = ConCache.get(@cache_id, @total_lassos_key) || 0
-    {:ok, %{"active_lassos" => active_lassos, "total_lassos" => total_lassos}}
-  end
-
-  defp notify_stats() do
-    with {:ok, stats} <- stats() do
-      notify_subscribers(@admin_events, {:stats, stats})
-    end
+    emit_stop({:action, %{action: :delete}}, 1)
+    :ok
   end
 
   defp update(uuid, request) do
@@ -129,4 +106,32 @@ defmodule Lasso do
       end
     end)
   end
+
+  defp with_telemetry_events(my_fn, path_meta) do
+    start_time = emit_start(path_meta)
+    result = my_fn.()
+    duration = System.monotonic_time() - start_time
+    emit_stop(path_meta, duration)
+    result
+  end
+
+  defp emit_start({path, meta}) do
+    start_time_mono = System.monotonic_time()
+
+    :telemetry.execute(
+      [:lasso, path, :start],
+      %{system_time: System.system_time()},
+      meta
+    )
+
+    start_time_mono
+  end
+
+  defp emit_stop({path, meta}, duration) do
+    :telemetry.execute(
+      [:lasso, path, :stop],
+      %{duration: duration},
+      meta
+    )
+  end
 end

lib/lasso/application.ex

@@ -1,12 +1,9 @@
 defmodule Lasso.Application do
-  # See https://hexdocs.pm/elixir/Application.html
-  # for more information on OTP Applications
   @moduledoc false
 
   use Application
 
   def start(_type, _args) do
-    # List all child processes to be supervised
     children = [
       {ConCache,
        [
@@ -17,10 +14,8 @@ defmodule Lasso.Application do
          callback: &Lasso.cache_callback/1
        ]},
       {Phoenix.PubSub, name: Lasso.PubSub},
-      # Start the endpoint when the application starts
+      LassoWeb.Telemetry,
       LassoWeb.Endpoint
-      # Starts a worker by calling: Lasso.Worker.start_link(arg)
-      # {Lasso.Worker, arg},
     ]
 
     # See https://hexdocs.pm/elixir/Supervisor.html

lib/lasso_web/router.ex

@@ -1,6 +1,7 @@
 defmodule LassoWeb.Router do
   use LassoWeb, :router
   import Phoenix.LiveView.Router
+  import Phoenix.LiveDashboard.Router
 
   pipeline :browser do
     plug :accepts, ["html"]
@@ -18,18 +19,26 @@ defmodule LassoWeb.Router do
     plug :accepts, ["json"]
   end
 
+  pipeline :admins_only do
+    plug BasicAuth, use_config: {:basic_auth, :admin_area}
+  end
+
   scope "/", LassoWeb do
     pipe_through :browser
 
     get "/", PageController, :index
-    get "/admin", AdminController, :index
 
     delete "/admin/lasso/:uuid", LassoViewController, :delete
     post "/admin/lasso/", LassoViewController, :new
 
     get "/lasso/:uuid/view", LassoViewController, :show
   end
 
+  scope "/admin" do
+    pipe_through [:browser, :admins_only]
+    live_dashboard "/", metrics: LassoWeb.Telemetry
+  end
+
   # The `get` here gets flagged by Sobelow as a potential for  "CSRF via Action Reuse"
   # It does not matter if a user can trigger the post request in this scenario.
   scope "/lasso", LassoWeb do

lib/lasso_web/telemetry.ex

@@ -0,0 +1,65 @@
+defmodule LassoWeb.Telemetry do
+  @moduledoc """
+  Metrics for the admin live dashboard
+  """
+
+  use Supervisor
+  import Telemetry.Metrics
+
+  def start_link(arg) do
+    Supervisor.start_link(__MODULE__, arg, name: __MODULE__)
+  end
+
+  @impl true
+  def init(_arg) do
+    children = [
+      # Telemetry poller will execute the given period measurements
+      # every 10_000ms. Learn more here: https://hexdocs.pm/telemetry_metrics
+      {:telemetry_poller, measurements: periodic_measurements(), period: 10_000}
+      # Add reporters as children of your supervision tree.
+      # {Telemetry.Metrics.ConsoleReporter, metrics: metrics()}
+    ]
+
+    Supervisor.init(children, strategy: :one_for_one)
+  end
+
+  def metrics do
+    [
+      # Phoenix Metrics
+      summary("phoenix.endpoint.stop.duration",
+        unit: {:native, :millisecond}
+      ),
+      summary("phoenix.router_dispatch.stop.duration",
+        tags: [:route],
+        unit: {:native, :millisecond}
+      ),
+
+      # Lasso specifics
+      summary("lasso.action.stop.duration",
+        tags: [:action],
+        tag_values: &action_tag_value/1,
+        unit: {:native, :millisecond}
+      ),
+      counter("lasso.action.stop.duration", tags: [:action], tag_values: &action_tag_value/1),
+      counter("lasso.request.stop.duration", tags: [:method], tag_values: &request_method_value/1),
+
+      # 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
+
+  defp action_tag_value(metadata) do
+    Map.take(metadata, [:action])
+  end
+
+  defp request_method_value(metadata) do
+    Map.take(metadata.request, [:method])
+  end
+end

mix.exs

@@ -44,6 +44,10 @@ defmodule Lasso.MixProject do
       {:elixir_uuid, "~> 1.2"},
       {:con_cache, "~> 0.13"},
       {:basic_auth, "~> 2.2"},
+      {:phoenix_live_dashboard, "~> 0.2"},
+      {:telemetry_poller, "~> 0.4"},
+      {:telemetry_metrics, "~> 0.4"},
+      {:telemetry, "~> 0.4"},
       {:credo, "~> 1.1", only: [:dev, :test], runtime: false},
       {:sobelow, "~> 0.8", only: :dev, runtime: false},
       {:floki, "~> 0.26", only: [:test], runtime: false}

mix.lock

@@ -14,13 +14,16 @@
   "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm", "6cbe761d6a0ca5a31a0931bf4c63204bceb64538e664a8ecf784a9a6f3b875f1"},
   "phoenix": {:hex, :phoenix, "1.5.3", "bfe0404e48ea03dfe17f141eff34e1e058a23f15f109885bbdcf62be303b49ff", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix_html, "~> 2.13", [hex: :phoenix_html, repo: "hexpm", optional: true]}, {:phoenix_pubsub, "~> 2.0", [hex: :phoenix_pubsub, repo: "hexpm", optional: false]}, {:plug, "~> 1.10", [hex: :plug, repo: "hexpm", optional: false]}, {:plug_cowboy, "~> 1.0 or ~> 2.2", [hex: :plug_cowboy, repo: "hexpm", optional: true]}, {:plug_crypto, "~> 1.1.2 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "8e16febeb9640d8b33895a691a56481464b82836d338bb3a23125cd7b6157c25"},
   "phoenix_html": {:hex, :phoenix_html, "2.14.2", "b8a3899a72050f3f48a36430da507dd99caf0ac2d06c77529b1646964f3d563e", [:mix], [{:plug, "~> 1.5", [hex: :plug, repo: "hexpm", optional: false]}], "hexpm", "58061c8dfd25da5df1ea0ca47c972f161beb6c875cd293917045b92ffe1bf617"},
+  "phoenix_live_dashboard": {:hex, :phoenix_live_dashboard, "0.2.4", "3080e8a89bab3ec08d4dd9a6858dfa24af9334464aae78c83e58a2db37c6f983", [:mix], [{:phoenix_html, "~> 2.14.1 or ~> 2.15", [hex: :phoenix_html, repo: "hexpm", optional: false]}, {:phoenix_live_view, "~> 0.12.0 or ~> 0.13.0", [hex: :phoenix_live_view, repo: "hexpm", optional: false]}, {:telemetry_metrics, "~> 0.4.0 or ~> 0.5.0", [hex: :telemetry_metrics, repo: "hexpm", optional: false]}], "hexpm", "1c89595ef60f1b76ac07705e73f001823af451491792a4b0d5b2b2a3789b0a00"},
   "phoenix_live_reload": {:hex, :phoenix_live_reload, "1.2.2", "38d94c30df5e2ef11000697a4fbe2b38d0fbf79239d492ff1be87bbc33bc3a84", [:mix], [{:file_system, "~> 0.2.1 or ~> 0.3", [hex: :file_system, repo: "hexpm", optional: false]}, {:phoenix, "~> 1.4", [hex: :phoenix, repo: "hexpm", optional: false]}], "hexpm", "a3dec3d28ddb5476c96a7c8a38ea8437923408bc88da43e5c45d97037b396280"},
-  "phoenix_live_view": {:hex, :phoenix_live_view, "0.12.1", "42f591c781edbf9fab921319076b7ac635d43aa23e6748d2644563326236d7e4", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.4.16 or ~> 1.5.0", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 2.14", [hex: :phoenix_html, repo: "hexpm", optional: false]}], "hexpm", "585321e98df1cd5943e370b9784e950a37ca073744eb534660c9048967c52ab6"},
+  "phoenix_live_view": {:hex, :phoenix_live_view, "0.13.0", "dec006b3da4ab164283d5bebe960724eb4d19cd0ed553e05fb99b260233e200f", [:mix], [{:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: true]}, {:phoenix, "~> 1.4.17 or ~> 1.5.0", [hex: :phoenix, repo: "hexpm", optional: false]}, {:phoenix_html, "~> 2.14", [hex: :phoenix_html, repo: "hexpm", optional: false]}], "hexpm", "bd6f13b666fa9bfeca88b013db20414c693d5a5e6d19b1fc2602c282d626ed8e"},
   "phoenix_pubsub": {:hex, :phoenix_pubsub, "2.0.0", "a1ae76717bb168cdeb10ec9d92d1480fec99e3080f011402c0a2d68d47395ffb", [:mix], [], "hexpm", "c52d948c4f261577b9c6fa804be91884b381a7f8f18450c5045975435350f771"},
   "plug": {:hex, :plug, "1.10.1", "c56a6d9da7042d581159bcbaef873ba9d87f15dce85420b0d287bca19f40f9bd", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: true]}], "hexpm", "b5cd52259817eb8a31f2454912ba1cff4990bca7811918878091cb2ab9e52cb8"},
   "plug_cowboy": {:hex, :plug_cowboy, "2.2.1", "fcf58aa33227a4322a050e4783ee99c63c031a2e7f9a2eb7340d55505e17f30f", [:mix], [{:cowboy, "~> 2.7", [hex: :cowboy, repo: "hexpm", optional: false]}, {:plug, "~> 1.7", [hex: :plug, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "3b43de24460d87c0971887286e7a20d40462e48eb7235954681a20cee25ddeb6"},
   "plug_crypto": {:hex, :plug_crypto, "1.1.2", "bdd187572cc26dbd95b87136290425f2b580a116d3fb1f564216918c9730d227", [], [], "hexpm", "6b8b608f895b6ffcfad49c37c7883e8df98ae19c6a28113b02aa1e9c5b22d6b5"},
   "ranch": {:hex, :ranch, "1.7.1", "6b1fab51b49196860b733a49c07604465a47bdb78aa10c1c16a3d199f7f8c881", [:rebar3], [], "hexpm", "451d8527787df716d99dc36162fca05934915db0b6141bbdac2ea8d3c7afc7d7"},
   "sobelow": {:hex, :sobelow, "0.10.2", "00e91208046d3b434f9f08779fe0ca7c6d6595b7fa33b289e792dffa6dde8081", [:mix], [], "hexpm", "e30fc994330cf6f485c1c4f2fb7c4b2d403557d0e101c6e5329fd17a58e55a7e"},
   "telemetry": {:hex, :telemetry, "0.4.1", "ae2718484892448a24470e6aa341bc847c3277bfb8d4e9289f7474d752c09c7f", [:rebar3], [], "hexpm", "4738382e36a0a9a2b6e25d67c960e40e1a2c95560b9f936d8e29de8cd858480f"},
+  "telemetry_metrics": {:hex, :telemetry_metrics, "0.5.0", "1b796e74add83abf844e808564275dfb342bcc930b04c7577ab780e262b0d998", [:mix], [{:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "31225e6ce7a37a421a0a96ec55244386aec1c190b22578bd245188a4a33298fd"},
+  "telemetry_poller": {:hex, :telemetry_poller, "0.5.0", "4770888ef85599ead39c7f51d6b4b62306e602d96c69b2625d54dea3d9a5204b", [:rebar3], [{:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "69e4e8e65b0ae077c9e14cd5f42c7cc486de0e07ac6e3409e6f0e52699a7872c"},
 }