fix: basic_elixir example app is not exporting tracing

Author: linomassarani

examples/basic_elixir/lib/basic_elixir/worker.ex

@@ -6,24 +6,7 @@ defmodule BasicElixir.Worker do
 
   # Client
   def start_link(default) when is_list(default) do
-    # Span names can be a binary or an atom. Atoms are preferred
-    # for memory efficiency.
-    Tracer.with_span :start_link do
-      # Span name rules also apply to events
-      Tracer.add_event("Nice operation!", %{"bogons" => 100})
-
-      # Attributes can be a map or a keyword list
-      Tracer.set_attributes(%{another_key: "yes"})
-
-      # Any attributes that can be known before starting a span
-      # should be passed on span creation so that they can be
-      # available for sampling decisions
-      Tracer.with_span "Sub operation...", %{attributes: [lemons_key: "five"]} do
-        Tracer.add_event("Sub span event!", [])
-      end
-
-      GenServer.start_link(__MODULE__, default)
-    end
+    GenServer.start_link(__MODULE__, default)
   end
 
   def push(pid, element) do
@@ -39,6 +22,7 @@ defmodule BasicElixir.Worker do
   def init(stack) do
     Tracer.with_span :init do
       Logger.info("Starting #{__MODULE__}...")
+      send(self(), :perform)
       {:ok, stack}
     end
   end
@@ -52,4 +36,45 @@ defmodule BasicElixir.Worker do
   def handle_cast({:push, element}, state) do
     {:noreply, [element | state]}
   end
+
+  @impl true
+  def handle_info(:perform, state) do
+    if otlp_exporter_initialized?() do
+      Logger.info("#{__MODULE__} - OTLP exporter initialized, performing...")
+      perform()
+      Logger.info("#{__MODULE__} - Perform completed")
+    else
+      Logger.info("#{__MODULE__} - OTLP exporter not initialized, performing in 1 second...")
+      perform_in_one_second()
+    end
+
+    {:noreply, state}
+  end
+
+  defp perform do
+    # Span names can be a binary or an atom. Atoms are preferred
+    # for memory efficiency.
+    Tracer.with_span :start_link do
+      # Span name rules also apply to events
+      Tracer.add_event("Nice operation!", %{"bogons" => 100})
+
+      # Attributes can be a map or a keyword list
+      Tracer.set_attributes(%{another_key: "yes"})
+
+      # Any attributes that can be known before starting a span
+      # should be passed on span creation so that they can be
+      # available for sampling decisions
+      Tracer.with_span "Sub operation...", %{attributes: [lemons_key: "five"]} do
+        Tracer.add_event("Sub span event!", [])
+      end
+    end
+  end
+
+  defp perform_in_one_second do
+    one_second = 1_000
+    Process.send_after(self(), :perform, one_second)
+  end
+
+  defp otlp_exporter_initialized?,
+    do: :persistent_term.get({:otel_batch_processor, :enabled_key, :otel_batch_processor_global})
 end