From 197a7a4c2ca848e1e71c4ec1188f7491ce6d9acc Mon Sep 17 00:00:00 2001
From: Brett McBride <brett.a.mcbride@gmail.com>
Date: Thu, 31 Aug 2023 09:23:20 +1000
Subject: [PATCH] optional internal metrics (#1106)

adding a configuration option OTEL_PHP_INTERNAL_METRICS_ENABLED which
controls whether the SDK will emit its own metrics (eg batch processor
state).
---
 examples/enabling_internal_metrics.php      | 24 +++++++++++++++++++++
 rector.php                                  |  1 -
 src/SDK/Common/Configuration/Defaults.php   |  1 +
 src/SDK/Common/Configuration/ValueTypes.php |  1 +
 src/SDK/Common/Configuration/Variables.php  |  1 +
 src/SDK/SdkAutoloader.php                   |  5 +++--
 tests/Unit/Context/ScopeTest.php            |  2 +-
 7 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 examples/enabling_internal_metrics.php

diff --git a/examples/enabling_internal_metrics.php b/examples/enabling_internal_metrics.php
new file mode 100644
index 000000000..ea3588a43
--- /dev/null
+++ b/examples/enabling_internal_metrics.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Example;
+
+use OpenTelemetry\API\Globals;
+
+/**
+ * The OpenTelemetry SDK is able to emit some metrics about its internal state. For example,
+ * batch span and log processor state.
+ * This feature can be enabled via the OTEL_PHP_INTERNAL_METRICS_ENABLED setting.
+ */
+
+putenv('OTEL_PHP_INTERNAL_METRICS_ENABLED=true');
+putenv('OTEL_PHP_AUTOLOAD_ENABLED=true');
+putenv('OTEL_TRACES_EXPORTER=console');
+putenv('OTEL_METRICS_EXPORTER=console');
+putenv('OTEL_LOGS_EXPORTER=console');
+
+require __DIR__ . '/../vendor/autoload.php';
+
+$tracerProvider = Globals::tracerProvider();
+$tracerProvider->getTracer('demo')->spanBuilder('root')->startSpan()->end();
diff --git a/rector.php b/rector.php
index e550e3de5..347905025 100644
--- a/rector.php
+++ b/rector.php
@@ -27,7 +27,6 @@
         FlipTypeControlToUseExclusiveTypeRector::class,
         \Rector\Strict\Rector\Empty_\DisallowedEmptyRuleFixerRector::class,
         \Rector\CodeQuality\Rector\If_\ExplicitBoolCompareRector::class,
-        \Rector\RemovingStatic\Rector\ClassMethod\LocallyCalledStaticMethodToNonStaticRector::class,
         \Rector\CodeQuality\Rector\ClassMethod\LocallyCalledStaticMethodToNonStaticRector::class,
     ]);
 };
diff --git a/src/SDK/Common/Configuration/Defaults.php b/src/SDK/Common/Configuration/Defaults.php
index e144de074..3ad59a63e 100644
--- a/src/SDK/Common/Configuration/Defaults.php
+++ b/src/SDK/Common/Configuration/Defaults.php
@@ -113,6 +113,7 @@ interface Defaults
     public const OTEL_PHP_TRACES_PROCESSOR = 'batch';
     public const OTEL_PHP_DETECTORS = 'all';
     public const OTEL_PHP_AUTOLOAD_ENABLED = 'false';
+    public const OTEL_PHP_INTERNAL_METRICS_ENABLED = 'false';
     public const OTEL_PHP_DISABLED_INSTRUMENTATIONS = [];
     public const OTEL_PHP_LOGS_PROCESSOR = 'batch';
 }
diff --git a/src/SDK/Common/Configuration/ValueTypes.php b/src/SDK/Common/Configuration/ValueTypes.php
index 96dce43d9..81f6b0142 100644
--- a/src/SDK/Common/Configuration/ValueTypes.php
+++ b/src/SDK/Common/Configuration/ValueTypes.php
@@ -119,5 +119,6 @@ interface ValueTypes
     public const OTEL_PHP_TRACES_PROCESSOR = VariableTypes::ENUM;
     public const OTEL_PHP_DETECTORS = VariableTypes::LIST;
     public const OTEL_PHP_AUTOLOAD_ENABLED = VariableTypes::BOOL;
+    public const OTEL_PHP_INTERNAL_METRICS_ENABLED = VariableTypes::BOOL;
     public const OTEL_PHP_DISABLED_INSTRUMENTATIONS = VariableTypes::LIST;
 }
diff --git a/src/SDK/Common/Configuration/Variables.php b/src/SDK/Common/Configuration/Variables.php
index 705c212aa..797c1651c 100644
--- a/src/SDK/Common/Configuration/Variables.php
+++ b/src/SDK/Common/Configuration/Variables.php
@@ -135,5 +135,6 @@ interface Variables
     public const OTEL_PHP_LOGS_PROCESSOR = 'OTEL_PHP_LOGS_PROCESSOR';
     public const OTEL_PHP_DETECTORS = 'OTEL_PHP_DETECTORS';
     public const OTEL_PHP_AUTOLOAD_ENABLED = 'OTEL_PHP_AUTOLOAD_ENABLED';
+    public const OTEL_PHP_INTERNAL_METRICS_ENABLED = 'OTEL_PHP_INTERNAL_METRICS_ENABLED'; //whether the SDK should emit its own metrics
     public const OTEL_PHP_DISABLED_INSTRUMENTATIONS = 'OTEL_PHP_DISABLED_INSTRUMENTATIONS';
 }
diff --git a/src/SDK/SdkAutoloader.php b/src/SDK/SdkAutoloader.php
index a426d1712..53079a915 100644
--- a/src/SDK/SdkAutoloader.php
+++ b/src/SDK/SdkAutoloader.php
@@ -40,16 +40,17 @@ public static function autoload(): bool
                 //@see https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/sdk-environment-variables.md#general-sdk-configuration
                 return $configurator->withPropagator($propagator);
             }
+            $emitMetrics = Configuration::getBoolean(Variables::OTEL_PHP_INTERNAL_METRICS_ENABLED);
 
             $exporter = (new ExporterFactory())->create();
             $meterProvider = (new MeterProviderFactory())->create();
-            $spanProcessor = (new SpanProcessorFactory())->create($exporter, $meterProvider);
+            $spanProcessor = (new SpanProcessorFactory())->create($exporter, $emitMetrics ? $meterProvider : null);
             $tracerProvider = (new TracerProviderBuilder())
                 ->addSpanProcessor($spanProcessor)
                 ->setSampler((new SamplerFactory())->create())
                 ->build();
 
-            $loggerProvider = (new LoggerProviderFactory())->create($meterProvider);
+            $loggerProvider = (new LoggerProviderFactory())->create($emitMetrics ? $meterProvider : null);
 
             ShutdownHandler::register([$tracerProvider, 'shutdown']);
             ShutdownHandler::register([$meterProvider, 'shutdown']);
diff --git a/tests/Unit/Context/ScopeTest.php b/tests/Unit/Context/ScopeTest.php
index 7f0c2b0ce..08149ada5 100644
--- a/tests/Unit/Context/ScopeTest.php
+++ b/tests/Unit/Context/ScopeTest.php
@@ -116,7 +116,7 @@ public function test_scope_local_storage_is_preserved_between_attach_and_scope()
         $scope['key'] = 'value';
         $scope = $storage->scope();
         $this->assertNotNull($scope);
-        $this->assertArrayHasKey('key', $scope); /** @phpstan-ignore-line */
+        $this->assertArrayHasKey('key', $scope);
         $this->assertSame('value', $scope['key']);
 
         unset($scope['key']);