From 548da527e4199f62b5f53fd30e5dc1eaf30e9bcd Mon Sep 17 00:00:00 2001
From: Bryan Naegele <bryan@fourthtime.com>
Date: Mon, 22 Jul 2024 20:51:10 -0600
Subject: [PATCH] Add semconv stability opt-in fun

---
 .../lib/sem_conv.ex                           | 15 ++++++++++
 .../mix.exs                                   |  1 -
 .../src/opentelemetry_sem_conv.erl            | 26 +++++++++++++++++
 .../semantic_conventions/sem_conv_test.exs    | 29 +++++++++++++++++++
 4 files changed, 70 insertions(+), 1 deletion(-)
 create mode 100644 apps/opentelemetry_semantic_conventions/src/opentelemetry_sem_conv.erl
 create mode 100644 apps/opentelemetry_semantic_conventions/test/open_telemetry/semantic_conventions/sem_conv_test.exs

diff --git a/apps/opentelemetry_semantic_conventions/lib/sem_conv.ex b/apps/opentelemetry_semantic_conventions/lib/sem_conv.ex
index ca3e58da..4211434e 100644
--- a/apps/opentelemetry_semantic_conventions/lib/sem_conv.ex
+++ b/apps/opentelemetry_semantic_conventions/lib/sem_conv.ex
@@ -115,4 +115,19 @@ defmodule OpenTelemetry.SemConv do
   attributes of both stability levels will have two modules in this case.
 
   """
+
+  @typedoc """
+  Stability opt-in value
+  """
+  @type stability_option() :: String.t()
+
+  @doc """
+  List of stability opt-ins defined by the `OTEL_SEMCONV_STABILITY_OPT_IN` env var.
+
+  Current valid options:
+
+  * [http](migration-guide.md)
+  """
+  @spec stability_opt_in() :: [stability_option()]
+  defdelegate stability_opt_in(), to: :opentelemetry_sem_conv
 end
diff --git a/apps/opentelemetry_semantic_conventions/mix.exs b/apps/opentelemetry_semantic_conventions/mix.exs
index 360a4e40..bf92ca10 100644
--- a/apps/opentelemetry_semantic_conventions/mix.exs
+++ b/apps/opentelemetry_semantic_conventions/mix.exs
@@ -100,6 +100,5 @@ defmodule OpenTelemetry.SemanticConventions.MixProject do
                  "guides/attributes-registry/signalr.md"
                ] ++ Path.wildcard("guides/dotnet/*") ++ Path.wildcard("guides/mobile/*"))
     end)
-    |> IO.inspect()
   end
 end
diff --git a/apps/opentelemetry_semantic_conventions/src/opentelemetry_sem_conv.erl b/apps/opentelemetry_semantic_conventions/src/opentelemetry_sem_conv.erl
new file mode 100644
index 00000000..ae6ae001
--- /dev/null
+++ b/apps/opentelemetry_semantic_conventions/src/opentelemetry_sem_conv.erl
@@ -0,0 +1,26 @@
+-module(opentelemetry_sem_conv).
+
+-export([stability_opt_in/0]).
+
+-export_type([stability_option/0]).
+
+-type stability_option() :: binary().
+
+-spec stability_opt_in() -> [stability_option()].
+stability_opt_in() ->
+  OptInsList = string:split(os:getenv("OTEL_SEMCONV_STABILITY_OPT_IN", ""), ","),
+  HttpStability = http_stability(OptInsList),
+  OptIns = [HttpStability],
+  lists:filter(fun(Opt) -> (Opt =/= undefined) end, OptIns).
+
+http_stability(OptIns) ->
+  Dup = lists:member("http/dup", OptIns),
+  Http = lists:member("http", OptIns),
+  case {Dup, Http} of
+    {true, _} ->
+      <<"http/dup">>;
+    {_, true} ->
+      <<"http">>;
+    _ ->
+      undefined
+  end.
diff --git a/apps/opentelemetry_semantic_conventions/test/open_telemetry/semantic_conventions/sem_conv_test.exs b/apps/opentelemetry_semantic_conventions/test/open_telemetry/semantic_conventions/sem_conv_test.exs
new file mode 100644
index 00000000..7620497d
--- /dev/null
+++ b/apps/opentelemetry_semantic_conventions/test/open_telemetry/semantic_conventions/sem_conv_test.exs
@@ -0,0 +1,29 @@
+defmodule OpenTelemetry.SemConvTest do
+  use ExUnit.Case, async: false
+
+  alias OpenTelemetry.SemConv
+
+  describe "stability_opt_in" do
+    test "http" do
+      assert SemConv.stability_opt_in() == []
+
+      System.put_env("OTEL_SEMCONV_STABILITY_OPT_IN", "")
+      assert SemConv.stability_opt_in() == []
+
+      System.put_env("OTEL_SEMCONV_STABILITY_OPT_IN", "unsupported")
+      assert SemConv.stability_opt_in() == []
+
+      System.put_env("OTEL_SEMCONV_STABILITY_OPT_IN", "http")
+      assert SemConv.stability_opt_in() == ["http"]
+
+      System.put_env("OTEL_SEMCONV_STABILITY_OPT_IN", "http/dup,http")
+      assert SemConv.stability_opt_in() == ["http/dup"]
+
+      # dup takes precedence
+      System.put_env("OTEL_SEMCONV_STABILITY_OPT_IN", "http,http/dup")
+      assert SemConv.stability_opt_in() == ["http/dup"]
+
+      System.delete_env("OTEL_SEMCONV_STABILITY_OPT_IN")
+    end
+  end
+end