Merge pull request #101 from appsignal/add-render-metadata-as-tags

Set render metadata as tags

.changesets/set-render-metadata-as-tags-on-render-error.md

@@ -0,0 +1,6 @@
+---
+bump: patch
+type: add
+---
+
+Set render metadata as tags on render error. When a template rendering error is reported, its backtrace is limited to the Elixir process that is spawned to render the template. Add information about the template and view being rendered as tags, to provide additional context about the error.

lib/appsignal_phoenix/event_handler.ex

@@ -106,6 +106,13 @@ defmodule Appsignal.Phoenix.EventHandler do
   def phoenix_template_render_start(_event, _measurements, metadata, _config) do
     parent = @tracer.current_span()
 
+    _ =
+      @span.set_sample_data_if_nil(@tracer.root_span(), "tags", %{
+        "phoenix_template" => metadata.template,
+        "phoenix_format" => metadata.format,
+        "phoenix_view" => module_name(metadata.view)
+      })
+
     "http_request"
     |> @tracer.create_span(parent)
     |> @span.set_name(

test/appsignal_phoenix/event_handler_test.exs

@@ -254,6 +254,18 @@ defmodule Appsignal.Phoenix.EventHandlerTest do
       assert {:ok, [{%Span{}, "appsignal:category", "render.phoenix_template"}]} =
                Test.Span.get(:set_attribute)
     end
+
+    test "sets the root span's tags" do
+      assert {:ok,
+              [
+                {%Span{}, "tags",
+                 %{
+                   "phoenix_template" => "template",
+                   "phoenix_format" => "html",
+                   "phoenix_view" => "PhoenixWeb.View"
+                 }}
+              ]} = Test.Span.get(:set_sample_data_if_nil)
+    end
   end
 
   describe "after receiving an render-start and an render-stop event" do