Add rule_psr and limit_psr metrics to improve trace ingestion rate (#45)

Author: mrz

lib/spandex_datadog/api_server.ex

@@ -177,7 +177,9 @@ defmodule SpandexDatadog.ApiServer do
       meta: meta(span),
       metrics:
         metrics(span, %{
-          _sampling_priority_v1: priority
+          _sampling_priority_v1: priority,
+          "_dd.rule_psr": 1.0,
+          "_dd.limit_psr": 1.0
         })
     }
   end

test/api_server_test.exs

@@ -178,7 +178,9 @@ defmodule SpandexDatadog.ApiServerTest do
             "zyx" => "[xyz: {1, 2}]"
           },
           "metrics" => %{
-            "_sampling_priority_v1" => 1
+            "_sampling_priority_v1" => 1,
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0
           },
           "name" => "foo",
           "resource" => "foo",
@@ -194,7 +196,9 @@ defmodule SpandexDatadog.ApiServerTest do
             "env" => "local"
           },
           "metrics" => %{
-            "_sampling_priority_v1" => 1
+            "_sampling_priority_v1" => 1,
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0
           },
           "name" => "bar",
           "resource" => "bar",
@@ -211,7 +215,9 @@ defmodule SpandexDatadog.ApiServerTest do
           },
           "metrics" => %{
             "_dd1.sr.eausr" => 1,
-            "_sampling_priority_v1" => 1
+            "_sampling_priority_v1" => 1,
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0
           },
           "name" => "bar",
           "resource" => "bar",
@@ -262,7 +268,9 @@ defmodule SpandexDatadog.ApiServerTest do
             "zyx" => "[xyz: {1, 2}]"
           },
           "metrics" => %{
-            "_sampling_priority_v1" => 1
+            "_sampling_priority_v1" => 1,
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0
           },
           "name" => "foo",
           "resource" => "foo",
@@ -278,7 +286,9 @@ defmodule SpandexDatadog.ApiServerTest do
             "env" => "local"
           },
           "metrics" => %{
-            "_sampling_priority_v1" => 1
+            "_sampling_priority_v1" => 1,
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0
           },
           "name" => "bar",
           "resource" => "bar",
@@ -294,6 +304,8 @@ defmodule SpandexDatadog.ApiServerTest do
             "env" => "local"
           },
           "metrics" => %{
+            "_dd.rule_psr" => 1.0,
+            "_dd.limit_psr" => 1.0,
             "_dd1.sr.eausr" => 1,
             "_sampling_priority_v1" => 1
           },