Add OTEL tracing to breakdown functions (#2544)

Co-authored-by: Robert Joonas <robertjoonas16@gmail.com>

Co-authored-by: Robert Joonas <robertjoonas16@gmail.com>

lib/plausible/stats/breakdown.ex

@@ -1,6 +1,7 @@
 defmodule Plausible.Stats.Breakdown do
   use Plausible.ClickhouseRepo
   import Plausible.Stats.{Base, Imported}
+  require OpenTelemetry.Tracer, as: Tracer
   alias Plausible.Stats.Query
   alias Plausible.Goals
   @no_ref "Direct / None"
@@ -9,7 +10,7 @@ defmodule Plausible.Stats.Breakdown do
   @session_metrics [:visits, :bounce_rate, :visit_duration]
   @event_props ["event:page", "event:page_match", "event:name"]
 
-  def breakdown(site, query, "event:goal", metrics, pagination) do
+  def breakdown(site, query, "event:goal" = property, metrics, pagination) do
     {event_goals, pageview_goals} =
       site.domain
       |> Goals.for_domain()
@@ -18,6 +19,8 @@ defmodule Plausible.Stats.Breakdown do
     events = Enum.map(event_goals, & &1.event_name)
     event_query = %Query{query | filters: Map.put(query.filters, "event:name", {:member, events})}
 
+    trace(query, property, metrics)
+
     event_results =
       if Enum.any?(event_goals) do
         breakdown(site, event_query, "event:name", metrics, pagination)
@@ -60,7 +63,7 @@ defmodule Plausible.Stats.Breakdown do
     zip_results(event_results, page_results, :goal, metrics)
   end
 
-  def breakdown(site, query, "event:props:" <> custom_prop, metrics, pagination) do
+  def breakdown(site, query, "event:props:" <> custom_prop = property, metrics, pagination) do
     {limit, _} = pagination
 
     none_result =
@@ -80,6 +83,7 @@ defmodule Plausible.Stats.Breakdown do
         []
       end
 
+    trace(query, property, metrics)
     results = breakdown_events(site, query, "event:props:" <> custom_prop, metrics, pagination)
 
     zipped = zip_results(none_result, results, custom_prop, metrics)
@@ -91,7 +95,7 @@ defmodule Plausible.Stats.Breakdown do
     end
   end
 
-  def breakdown(site, query, "event:page", metrics, pagination) do
+  def breakdown(site, query, "event:page" = property, metrics, pagination) do
     event_metrics = Enum.filter(metrics, &(&1 in @event_metrics))
     session_metrics = Enum.filter(metrics, &(&1 in @session_metrics))
 
@@ -118,6 +122,8 @@ defmodule Plausible.Stats.Breakdown do
           Query.put_filter(query, "visit:entry_page", {:member, Enum.map(pages, & &1[:page])})
       end
 
+    trace(new_query, property, metrics)
+
     if Enum.any?(event_metrics) && Enum.empty?(event_result) do
       []
     else
@@ -140,6 +146,7 @@ defmodule Plausible.Stats.Breakdown do
   end
 
   def breakdown(site, query, property, metrics, pagination) when property in @event_props do
+    trace(query, property, metrics)
     breakdown_events(site, query, property, metrics, pagination)
   end
 
@@ -157,10 +164,12 @@ defmodule Plausible.Stats.Breakdown do
       |> Query.treat_page_filter_as_entry_page()
       |> Query.treat_prop_filter_as_entry_prop()
 
+    trace(query, property, metrics)
     breakdown_sessions(site, query, property, metrics, pagination)
   end
 
   def breakdown(site, query, property, metrics, pagination) do
+    trace(query, property, metrics)
     breakdown_sessions(site, query, property, metrics, pagination)
   end
 
@@ -555,4 +564,13 @@ defmodule Plausible.Stats.Breakdown do
     |> Ecto.Query.limit(^limit)
     |> Ecto.Query.offset(^offset)
   end
+
+  defp trace(query, property, metrics) do
+    Query.trace(query)
+
+    Tracer.set_attributes([
+      {"plausible.query.breakdown_property", property},
+      {"plausible.query.breakdown_metrics", metrics}
+    ])
+  end
 end

lib/plausible/stats/query.ex

@@ -7,6 +7,7 @@ defmodule Plausible.Stats.Query do
             include_imported: false
 
   @default_sample_threshold 20_000_000
+  require OpenTelemetry.Tracer, as: Tracer
   alias Plausible.Stats.{FilterParser, Interval}
 
   def shift_back(%__MODULE__{period: "year"} = query, site) do
@@ -336,4 +337,15 @@ defmodule Plausible.Stats.Query do
 
     %{query | include_imported: !!include_imported}
   end
+
+  @spec trace(%__MODULE__{}) :: %__MODULE__{}
+  def trace(%__MODULE__{} = query) do
+    Tracer.set_attributes([
+      {"plausible.query.interval", query.interval},
+      {"plausible.query.period", query.period},
+      {"plausible.query.include_imported", query.include_imported}
+    ])
+
+    query
+  end
 end