Add :telemetry events for callback start and stop

Author: FelonEkonom

lib/membrane/bin.ex

@@ -348,6 +348,10 @@ defmodule Membrane.Bin do
 
       Membrane.Core.Child.PadsSpecs.ensure_default_membrane_pads()
 
+      @doc false
+      @spec membrane_component_type() :: :pipeline | :bin | :element
+      def membrane_component_type, do: :bin
+
       @doc false
       @spec membrane_bin?() :: true
       def membrane_bin?, do: true

lib/membrane/core/callback_handler.ex

@@ -136,7 +136,23 @@ defmodule Membrane.Core.CallbackHandler do
 
     callback_result =
       try do
-        apply(module, callback, args)
+        telemetry_metadata = %{
+          callback_args: args,
+          parent_pid: state[:parent_pid],
+          type: state.module.membrane_component_type()
+        }
+
+        :telemetry.execute([:membrane, callback, :start], %{}, telemetry_metadata)
+
+        {duration, result} = :timer.tc(module, callback, args)
+
+        :telemetry.execute(
+          [:membrane, callback, :stop],
+          %{duration: duration},
+          telemetry_metadata
+        )
+
+        result
       rescue
         e in UndefinedFunctionError ->
           _ignored =

lib/membrane/element/base.ex

@@ -263,6 +263,10 @@ defmodule Membrane.Element.Base do
 
       unquote(bring_pad)
 
+      @doc false
+      @spec membrane_component_type() :: :pipeline | :bin | :element
+      def membrane_component_type, do: :element
+
       @doc false
       @spec membrane_element?() :: true
       def membrane_element?, do: true

lib/membrane/pipeline.ex

@@ -512,6 +512,10 @@ defmodule Membrane.Pipeline do
         }
       end
 
+      @doc false
+      @spec membrane_component_type() :: :pipeline | :bin | :element
+      def membrane_component_type, do: :pipeline
+
       @doc false
       @spec membrane_pipeline?() :: true
       def membrane_pipeline?, do: true