From c0b2afb7d4a7c09aa59aa62542fd4cc763c12f67 Mon Sep 17 00:00:00 2001
From: alejandro-fr <99.alejandro.flores@gmail.com>
Date: Thu, 6 Apr 2023 12:20:08 -0600
Subject: [PATCH 1/2] try to first fetch self ctx in run start

---
 .../lib/opentelemetry_dataloader.ex           | 31 +++++++++++++++++--
 1 file changed, 29 insertions(+), 2 deletions(-)

diff --git a/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex b/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
index 238fb652..68d2df0e 100644
--- a/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
+++ b/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
@@ -45,10 +45,17 @@ defmodule OpentelemetryDataloader do
   def handle_event(event, measurements, metadata, config)
 
   def handle_event(@run_start, _measurements, metadata, config) do
-    parent_ctx = OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
+    parent_ctx =
+      case OpentelemetryProcessPropagator.fetch_ctx(self()) do
+        :undefined ->
+          OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
+
+        ctx ->
+          ctx
+      end
 
     if parent_ctx != :undefined do
-      OpenTelemetry.Ctx.attach(parent_ctx)
+      attach_parent_ctx(parent_ctx)
     end
 
     OpentelemetryTelemetry.start_telemetry_span(
@@ -65,6 +72,8 @@ defmodule OpentelemetryDataloader do
     OpentelemetryTelemetry.set_current_telemetry_span(config.tracer_id, metadata)
 
     OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
+
+    detach_parent_ctx()
   end
 
   def handle_event(@batch_start, _measurements, metadata, config) do
@@ -96,4 +105,22 @@ defmodule OpentelemetryDataloader do
 
     OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
   end
+
+  @ctx_key {__MODULE__, :parent_ctx}
+
+  defp attach_parent_ctx(parent_ctx) do
+    parent_token = OpenTelemetry.Ctx.attach(parent_ctx)
+
+    Process.put(@ctx_key, parent_token)
+  end
+
+  defp detach_parent_ctx() do
+    parent_ctx = Process.get(@ctx_key, :undefined)
+
+    if parent_ctx != :undefined do
+      @ctx_key
+      |> Process.delete()
+      |> OpenTelemetry.Ctx.detach()
+    end
+  end
 end

From 22885e1d3ccd10f72db4f18605b004b9d92a199b Mon Sep 17 00:00:00 2001
From: alejandro-fr <99.alejandro.flores@gmail.com>
Date: Mon, 10 Jul 2023 13:43:07 -0600
Subject: [PATCH 2/2] remove self attach and parent detach

---
 .../lib/opentelemetry_dataloader.ex           | 34 +++----------------
 1 file changed, 4 insertions(+), 30 deletions(-)

diff --git a/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex b/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
index 68d2df0e..f1e757f4 100644
--- a/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
+++ b/instrumentation/opentelemetry_dataloader/lib/opentelemetry_dataloader.ex
@@ -45,17 +45,11 @@ defmodule OpentelemetryDataloader do
   def handle_event(event, measurements, metadata, config)
 
   def handle_event(@run_start, _measurements, metadata, config) do
-    parent_ctx =
-      case OpentelemetryProcessPropagator.fetch_ctx(self()) do
-        :undefined ->
-          OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
-
-        ctx ->
-          ctx
-      end
+    self_ctx = OpentelemetryProcessPropagator.fetch_ctx(self())
+    parent_ctx = OpentelemetryProcessPropagator.fetch_parent_ctx(4, :"$callers")
 
-    if parent_ctx != :undefined do
-      attach_parent_ctx(parent_ctx)
+    if self_ctx == :undefined and parent_ctx != :undefined do
+      OpenTelemetry.Ctx.attach(parent_ctx)
     end
 
     OpentelemetryTelemetry.start_telemetry_span(
@@ -72,8 +66,6 @@ defmodule OpentelemetryDataloader do
     OpentelemetryTelemetry.set_current_telemetry_span(config.tracer_id, metadata)
 
     OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
-
-    detach_parent_ctx()
   end
 
   def handle_event(@batch_start, _measurements, metadata, config) do
@@ -105,22 +97,4 @@ defmodule OpentelemetryDataloader do
 
     OpentelemetryTelemetry.end_telemetry_span(config.tracer_id, metadata)
   end
-
-  @ctx_key {__MODULE__, :parent_ctx}
-
-  defp attach_parent_ctx(parent_ctx) do
-    parent_token = OpenTelemetry.Ctx.attach(parent_ctx)
-
-    Process.put(@ctx_key, parent_token)
-  end
-
-  defp detach_parent_ctx() do
-    parent_ctx = Process.get(@ctx_key, :undefined)
-
-    if parent_ctx != :undefined do
-      @ctx_key
-      |> Process.delete()
-      |> OpenTelemetry.Ctx.detach()
-    end
-  end
 end