Move actvity monitoring state into a GenSever and add calls from ea…

…ch GQL field

lib/gql_preferences/activity_monitor.ex

@@ -1,5 +1,6 @@
 defmodule ActivityMonitor do
-  @activity_server GenServer.whereis(ActivityServer)
-  def update_resolver_activity(key), do: @activity_server |> GenServer.cast({:update, key})
-  def fetch_resolver_activity(key), do: @activity_server |> GenServer.call({:get, key})
+  def update_resolver_activity(key), do: context() |> GenServer.cast({:update, key})
+  def fetch_resolver_activity(key), do: context() |> GenServer.call({:get, key})
+
+  defp context(), do: GenServer.whereis(ActivityServer)
 end

lib/gql_preferences/activity_server.ex

@@ -0,0 +1,18 @@
+defmodule ActivityServer do
+  use GenServer
+
+  def start_link(_), do: GenServer.start_link(__MODULE__, %{}, name: ActivityServer)
+  def init(_), do: {:ok, %{}}
+
+  def handle_cast({:update, key}, state) do
+    {:noreply, Map.update(state, key, 1, &(&1 + 1))}
+  end
+
+  def handle_call({:get, key}, _from, state) do
+    if Map.has_key?(state, key) do
+      {:reply, {:ok, Map.get(state, key)}, state}
+    else
+      {:reply, {:error, "Requested key: #{key} is invalid"}, state}
+    end
+  end
+end

lib/gql_preferences/application.ex

@@ -4,6 +4,7 @@ defmodule UserPreferences.Application do
   @moduledoc false
 
   use Application
+  alias ActivityServer
 
   @impl true
   def start(_type, _args) do
@@ -15,9 +16,10 @@ defmodule UserPreferences.Application do
       # Start the PubSub system
       {Phoenix.PubSub, name: UserPreferences.PubSub},
       # Start the Endpoint (http/https)
-      UserPreferencesWeb.Endpoint
+      UserPreferencesWeb.Endpoint,
       # Start a worker by calling: UserPreferences.Worker.start_link(arg)
       # {UserPreferences.Worker, arg}
+      ActivityServer
     ]
 
     # See https://hexdocs.pm/elixir/Supervisor.html

lib/gql_preferences_web/resolvers/activity.ex

@@ -0,0 +1,6 @@
+defmodule UserPreferencesWeb.Resolvers.Activity do
+  def get_activity(_, args, _) do
+    ActivityMonitor.update_resolver_activity("get_activity")
+    ActivityMonitor.fetch_resolver_activity(args.key)
+  end
+end

lib/gql_preferences_web/resolvers/preferences.ex

@@ -2,12 +2,22 @@ defmodule UserPreferencesWeb.Resolvers.Preferences do
   alias UserPreferences.{Repo, Preferences}
 
   def get_preferences(parent, _args, _) do
+    ActivityMonitor.update_resolver_activity("get_preferences")
+
     Preferences
     |> Repo.get_by(user_id: parent.id)
     |> then(&{:ok, &1})
   end
 
+  def create_preferences(args) do
+    %Preferences{}
+    |> Preferences.changeset(args)
+    |> Repo.insert()
+  end
+
   def update_preferences_by_id(_, args, _) do
+    ActivityMonitor.update_resolver_activity("update_preferences_by_id")
+
     Repo.get_by(Preferences, user_id: args.user_id)
     |> Preferences.changeset(args)
     |> Repo.update()

lib/gql_preferences_web/resolvers/users.ex

@@ -1,35 +1,43 @@
 defmodule UserPreferencesWeb.Resolvers.Users do
-  alias UserPreferences.{Repo, User, Preferences}
+  alias UserPreferences.{Repo, User}
+  alias UserPreferencesWeb.Resolvers
 
-  def get_user_by_id(_parent, args, _res), do: {:ok, Repo.get(User, args.id)}
+  def get_user_by_id(_parent, args, _res) do
+    ActivityMonitor.update_resolver_activity("get_user_by_id")
+    {:ok, Repo.get(User, args.id)}
+  end
+
+  def get_all_users(_, args, _) do
+    ActivityMonitor.update_resolver_activity("get_all_users")
 
-  def get_all_users(_, args, _),
-    do:
-      Absinthe.Relay.Connection.from_query(
-        User,
-        &Repo.all/1,
-        args
-      )
+    Absinthe.Relay.Connection.from_query(
+      User,
+      &Repo.all/1,
+      args
+    )
+  end
 
   def create_user(_parent, args, _res) do
+    ActivityMonitor.update_resolver_activity("create_user")
+
     {:ok, user} =
       %User{}
       |> User.changeset(args)
       |> Repo.insert()
 
-    pref_args = Map.put(args.preferences, :user_id, user.id)
-
     {:ok, pref} =
-      %Preferences{}
-      |> Preferences.changeset(pref_args)
-      |> Repo.insert()
+      args.preferences
+      |> Map.put(:user_id, user.id)
+      |> Resolvers.Preferences.create_preferences()
 
     res = Map.put(user, :preferences, pref)
 
     {:ok, res}
   end
 
   def update_user(_, args, _) do
+    ActivityMonitor.update_resolver_activity("update_user")
+
     Repo.get(User, args.id)
     |> User.changeset(args)
     |> Repo.update()

lib/gql_preferences_web/schema.ex

@@ -5,34 +5,17 @@ defmodule UserPreferencesWeb.Schema do
 
   alias UserPreferencesWeb.Resolvers
 
-  connection(node_type: :user)
-
-  node interface do
-    resolve_type(fn
-      %UserPreferences.User{}, _ ->
-        :user
-
-      _, _ ->
-        nil
-    end)
-  end
-
   query do
-    node field do
-      resolve(fn
-        %{type: :user, id: local_id}, _ ->
-          {:ok, UserPreferences.Repo.get(UserPreferences.User, local_id)}
-
-        _, _ ->
-          {:error, "Unknown node"} |> IO.inspect()
-      end)
-    end
-
     field :user, :user do
       arg(:id, non_null(:id))
       resolve(&Resolvers.Users.get_user_by_id/3)
     end
 
+    field :resolver_hits, :integer do
+      arg(:key, non_null(:string))
+      resolve(&Resolvers.Activity.get_activity/3)
+    end
+
     connection field :users, node_type: :user do
       arg(:before, :integer)
       arg(:after, :integer)
@@ -42,6 +25,16 @@ defmodule UserPreferencesWeb.Schema do
       arg(:likes_phone_calls, :boolean)
       resolve(&Resolvers.Users.get_all_users/3)
     end
+
+    node field do
+      resolve(fn
+        %{type: :user, id: local_id}, _ ->
+          {:ok, UserPreferences.Repo.get(UserPreferences.User, local_id)}
+
+        _, _ ->
+          {:error, "Unknown node"} |> IO.inspect()
+      end)
+    end
   end
 
   mutation do
@@ -67,6 +60,18 @@ defmodule UserPreferencesWeb.Schema do
     end
   end
 
+  connection(node_type: :user)
+
+  node interface do
+    resolve_type(fn
+      %UserPreferences.User{}, _ ->
+        :user
+
+      _, _ ->
+        nil
+    end)
+  end
+
   node object(:user) do
     field :id, :id
     field :name, :string
@@ -84,6 +89,11 @@ defmodule UserPreferencesWeb.Schema do
     field :likes_phone_calls, :boolean
   end
 
+  node object(:resolver_hits) do
+    field :key, :string
+    field :hits, :integer
+  end
+
   input_object :preferences_input do
     field :likes_emails, non_null(:boolean)
     field :likes_phone_calls, non_null(:boolean)