remove global configuration resolver (#1118)

Exposing it through Globals can cause a race condition. If something (eg, a contrib module)
retrieves the configuration resolver from Globals too early during autoloading, then it
causes the rest of the objects from Globals to be initialized. This can happen before all
required modules have been registered (depending on autoload->files execution order, which
is variable). Instead, create a simple API config resolver which does the basics of what the
SDK one does (without all the type checking and validation).

Author: brettmc

Behavior/Internal/LogWriterFactory.php

@@ -9,7 +9,7 @@
 use OpenTelemetry\API\Behavior\Internal\LogWriter\NoopLogWriter;
 use OpenTelemetry\API\Behavior\Internal\LogWriter\Psr3LogWriter;
 use OpenTelemetry\API\Behavior\Internal\LogWriter\StreamLogWriter;
-use OpenTelemetry\API\Globals;
+use OpenTelemetry\API\Instrumentation\ConfigurationResolver;
 use OpenTelemetry\API\LoggerHolder;
 
 class LogWriterFactory
@@ -18,16 +18,7 @@ class LogWriterFactory
 
     public function create(): LogWriterInterface
     {
-        $dest = Globals::configurationResolver()->getEnum(self::OTEL_PHP_LOG_DESTINATION);
-        //we might not have an SDK, so attempt to get from environment
-        if (!$dest) {
-            $dest = array_key_exists(self::OTEL_PHP_LOG_DESTINATION, $_SERVER)
-                ? $_SERVER[self::OTEL_PHP_LOG_DESTINATION]
-                : getenv(self::OTEL_PHP_LOG_DESTINATION);
-        }
-        if (!$dest) {
-            $dest = ini_get(self::OTEL_PHP_LOG_DESTINATION);
-        }
+        $dest = (new ConfigurationResolver())->getString(self::OTEL_PHP_LOG_DESTINATION);
         $logger = LoggerHolder::get();
 
         switch ($dest) {

Globals.php

@@ -7,7 +7,6 @@
 use function assert;
 use Closure;
 use const E_USER_WARNING;
-use OpenTelemetry\API\Instrumentation\ConfigurationResolverInterface;
 use OpenTelemetry\API\Instrumentation\Configurator;
 use OpenTelemetry\API\Instrumentation\ContextKeys;
 use OpenTelemetry\API\Logs\LoggerProviderInterface;
@@ -32,20 +31,17 @@ final class Globals
     private MeterProviderInterface $meterProvider;
     private TextMapPropagatorInterface $propagator;
     private LoggerProviderInterface $loggerProvider;
-    private ConfigurationResolverInterface $configurationResolver;
 
     public function __construct(
         TracerProviderInterface $tracerProvider,
         MeterProviderInterface $meterProvider,
         LoggerProviderInterface $loggerProvider,
-        TextMapPropagatorInterface $propagator,
-        ConfigurationResolverInterface $configurationResolver
+        TextMapPropagatorInterface $propagator
     ) {
         $this->tracerProvider = $tracerProvider;
         $this->meterProvider = $meterProvider;
         $this->loggerProvider = $loggerProvider;
         $this->propagator = $propagator;
-        $this->configurationResolver = $configurationResolver;
     }
 
     public static function tracerProvider(): TracerProviderInterface
@@ -68,11 +64,6 @@ public static function loggerProvider(): LoggerProviderInterface
         return Context::getCurrent()->get(ContextKeys::loggerProvider()) ?? self::globals()->loggerProvider;
     }
 
-    public static function configurationResolver(): ConfigurationResolverInterface
-    {
-        return Context::getCurrent()->get(ContextKeys::configurationResolver()) ?? self::globals()->configurationResolver;
-    }
-
     /**
      * @param Closure(Configurator): Configurator $initializer
      *
@@ -113,11 +104,10 @@ private static function globals(): self
         $meterProvider = $context->get(ContextKeys::meterProvider());
         $propagator = $context->get(ContextKeys::propagator());
         $loggerProvider = $context->get(ContextKeys::loggerProvider());
-        $configurationResolver = $context->get(ContextKeys::configurationResolver());
 
-        assert(isset($tracerProvider, $meterProvider, $loggerProvider, $propagator, $configurationResolver));
+        assert(isset($tracerProvider, $meterProvider, $loggerProvider, $propagator));
 
-        return self::$globals = new self($tracerProvider, $meterProvider, $loggerProvider, $propagator, $configurationResolver);
+        return self::$globals = new self($tracerProvider, $meterProvider, $loggerProvider, $propagator);
     }
 
     /**

Instrumentation/ConfigurationResolver.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\API\Instrumentation;
+
+class ConfigurationResolver implements ConfigurationResolverInterface
+{
+    public function has(string $name): bool
+    {
+        return $this->getVariable($name) !== null;
+    }
+
+    public function getString(string $name): ?string
+    {
+        return $this->getVariable($name);
+    }
+
+    public function getBoolean(string $name): ?bool
+    {
+        $value = $this->getVariable($name);
+        if ($value === null) {
+            return null;
+        }
+
+        return ($value === 'true');
+    }
+
+    public function getInt(string $name): ?int
+    {
+        $value = $this->getVariable($name);
+        if ($value === null) {
+            return null;
+        }
+        if (filter_var($value, FILTER_VALIDATE_INT) === false) {
+            //log warning
+            return null;
+        }
+
+        return (int) $value;
+    }
+
+    public function getList(string $name): array
+    {
+        $value = $this->getVariable($name);
+        if ($value === null) {
+            return [];
+        }
+
+        return explode(',', $value);
+    }
+
+    private function getVariable(string $name): ?string
+    {
+        $value = $_SERVER[$name] ?? null;
+        if ($value !== false && !self::isEmpty($value)) {
+            assert(is_string($value));
+
+            return $value;
+        }
+        $value = getenv($name);
+        if ($value !== false && !self::isEmpty($value)) {
+            return $value;
+        }
+        $value = ini_get($name);
+        if ($value !== false && !self::isEmpty($value)) {
+            return $value;
+        }
+
+        return null;
+    }
+
+    private static function isEmpty($value): bool
+    {
+        return $value === false || $value === null || $value === '';
+    }
+}

Instrumentation/ConfigurationResolverInterface.php

@@ -11,5 +11,4 @@ public function getString(string $name): ?string;
     public function getBoolean(string $name): ?bool;
     public function getInt(string $name): ?int;
     public function getList(string $name): array;
-    public function getEnum(string $name): ?string;
 }

Instrumentation/Configurator.php

@@ -28,7 +28,6 @@ final class Configurator implements ImplicitContextKeyedInterface
     private ?MeterProviderInterface $meterProvider = null;
     private ?TextMapPropagatorInterface $propagator = null;
     private ?LoggerProviderInterface $loggerProvider = null;
-    private ?ConfigurationResolverInterface $configurationResolver = null;
 
     private function __construct()
     {
@@ -52,7 +51,6 @@ public static function createNoop(): Configurator
             ->withMeterProvider(new NoopMeterProvider())
             ->withPropagator(new NoopTextMapPropagator())
             ->withLoggerProvider(new NoopLoggerProvider())
-            ->withConfigurationResolver(new NoopConfigurationResolver())
         ;
     }
 
@@ -77,9 +75,6 @@ public function storeInContext(?ContextInterface $context = null): ContextInterf
         if ($this->loggerProvider !== null) {
             $context = $context->with(ContextKeys::loggerProvider(), $this->loggerProvider);
         }
-        if ($this->configurationResolver !== null) {
-            $context = $context->with(ContextKeys::configurationResolver(), $this->configurationResolver);
-        }
 
         return $context;
     }
@@ -115,12 +110,4 @@ public function withLoggerProvider(?LoggerProviderInterface $loggerProvider): Co
 
         return $self;
     }
-
-    public function withConfigurationResolver(?ConfigurationResolverInterface $configurationResolver): Configurator
-    {
-        $self = clone $this;
-        $self->configurationResolver = $configurationResolver;
-
-        return $self;
-    }
 }

Instrumentation/ContextKeys.php

@@ -55,14 +55,4 @@ public static function loggerProvider(): ContextKeyInterface
 
         return $instance ??= Context::createKey(LoggerProviderInterface::class);
     }
-
-    /**
-     * @return ContextKeyInterface<ConfigurationResolverInterface>
-     */
-    public static function configurationResolver(): ContextKeyInterface
-    {
-        static $instance;
-
-        return $instance ??= Context::createKey(ConfigurationResolverInterface::class);
-    }
 }