fix: passing custom oban attributes to span

Author: yordis

instrumentation/opentelemetry_oban/lib/opentelemetry_oban/plugin_handler.ex

@@ -1,4 +1,6 @@
 defmodule OpentelemetryOban.PluginHandler do
+  require OpenTelemetry.Tracer, as: Tracer
+
   alias OpenTelemetry.Span
 
   @tracer_id __MODULE__
@@ -41,11 +43,12 @@ defmodule OpentelemetryOban.PluginHandler do
       @tracer_id,
       "#{plugin} process",
       metadata,
-      %{}
+      %{attributes: %{"oban.plugin" => plugin}}
     )
   end
 
   def handle_plugin_stop(_event, _measurements, metadata, _config) do
+    Tracer.set_attributes(end_span_plugin_attrs(metadata))
     OpentelemetryTelemetry.end_telemetry_span(@tracer_id, metadata)
   end
 
@@ -63,4 +66,24 @@ defmodule OpentelemetryOban.PluginHandler do
 
     OpentelemetryTelemetry.end_telemetry_span(@tracer_id, metadata)
   end
+
+  defp end_span_plugin_attrs(%{plugin: Oban.Plugins.Cron} = metadata) do
+    %{jobs_count: length(metadata[:jobs])}
+  end
+
+  defp end_span_plugin_attrs(%{plugin: Oban.Plugins.Gossip} = metadata) do
+    Map.take(metadata, [:gossip_count])
+  end
+
+  defp end_span_plugin_attrs(%{plugin: Oban.Plugins.Lifeline} = metadata) do
+    Map.take(metadata, [:discarded_count, :rescued_count])
+  end
+
+  defp end_span_plugin_attrs(%{plugin: Oban.Plugins.Pruner} = metadata) do
+    Map.take(metadata, [:pruned_count])
+  end
+
+  defp end_span_plugin_attrs(_) do
+    %{}
+  end
 end