1 files changed, 216 insertions, 0 deletions
diff --git a/classes/Tracer.php b/classes/Tracer.php
new file mode 100644
index 000000000..7163adb90
--- /dev/null
+++ b/classes/Tracer.php
@@ -0,0 +1,216 @@
+<?php
+
+use OpenTelemetry\API\Trace\Propagation\TraceContextPropagator;
+use OpenTelemetry\API\Trace\SpanContextInterface;
+use OpenTelemetry\API\Trace\SpanInterface;
+use OpenTelemetry\API\Trace\SpanKind;
+use OpenTelemetry\API\Trace\TraceFlags;
+use OpenTelemetry\API\Trace\TraceStateInterface;
+use OpenTelemetry\Context\ContextInterface;
+use OpenTelemetry\Context\ContextKey;
+use OpenTelemetry\Context\ContextKeyInterface;
+use OpenTelemetry\Context\ImplicitContextKeyedInterface;
+use OpenTelemetry\Context\ScopeInterface;
+use OpenTelemetry\Contrib\Otlp\OtlpHttpTransportFactory;
+use OpenTelemetry\Contrib\Otlp\SpanExporter;
+use OpenTelemetry\SDK\Common\Attribute\Attributes;
+use OpenTelemetry\SDK\Resource\ResourceInfo;
+use OpenTelemetry\SDK\Resource\ResourceInfoFactory;
+use OpenTelemetry\SDK\Trace\Sampler\AlwaysOnSampler;
+use OpenTelemetry\SDK\Trace\Sampler\ParentBased;
+use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+use OpenTelemetry\SemConv\ResourceAttributes;
+
+class DummyContextInterface implements ContextInterface {
+
+	/** @var DummyContextInterface */
+	private static $instance;
+
+	public function __construct() {
+		self::$instance = $this;
+	}
+
+	/** @phpstan-ignore-next-line */
+	public static function createKey(string $key): ContextKeyInterface { return new ContextKey(); }
+
+	public static function getCurrent(): ContextInterface { return self::$instance; }
+
+	public function activate(): ScopeInterface { return new DummyScopeInterface(); }
+
+	public function with(ContextKeyInterface $key, $value): ContextInterface { return $this; }
+
+	public function withContextValue(ImplicitContextKeyedInterface $value): ContextInterface { return $this; }
+
+	public function get(ContextKeyInterface $key) { return new ContextKey(); }
+
+}
+
+class DummySpanContextInterface implements SpanContextInterface {
+
+	/** @var DummySpanContextInterface $instance */
+	private static $instance;
+
+	public function __construct() {
+		self::$instance = $this;
+	}
+
+	public static function createFromRemoteParent(string $traceId, string $spanId, int $traceFlags = TraceFlags::DEFAULT, ?TraceStateInterface $traceState = null): SpanContextInterface { return self::$instance; }
+
+	public static function getInvalid(): SpanContextInterface { return self::$instance; }
+
+	public static function create(string $traceId, string $spanId, int $traceFlags = TraceFlags::DEFAULT, ?TraceStateInterface $traceState = null): SpanContextInterface { return self::$instance; }
+
+	public function getTraceId(): string { return ""; }
+
+	public function getTraceIdBinary(): string { return ""; }
+
+	public function getSpanId(): string { return ""; }
+
+	public function getSpanIdBinary(): string { return ""; }
+
+	public function getTraceFlags(): int { return 0; }
+
+	public function getTraceState(): ?TraceStateInterface { return null; }
+
+	public function isValid(): bool { return false; }
+
+	public function isRemote(): bool { return false; }
+
+	public function isSampled(): bool { return false; }
+}
+
+class DummyScopeInterface implements ScopeInterface {
+	public function detach(): int { return 0; }
+}
+
+class DummySpanInterface implements SpanInterface {
+
+	/** @var DummySpanInterface $instance */
+	private static $instance;
+
+	public function __construct() {
+		self::$instance = $this;
+	}
+
+	public static function fromContext(ContextInterface $context): SpanInterface { return self::$instance; }
+
+	public static function getCurrent(): SpanInterface { return self::$instance; }
+
+	public static function getInvalid(): SpanInterface { return self::$instance; }
+
+	public static function wrap(SpanContextInterface $spanContext): SpanInterface { return self::$instance; }
+
+	public function getContext(): SpanContextInterface { return new DummySpanContextInterface(); }
+
+	public function isRecording(): bool { return false; }
+
+	/** @phpstan-ignore-next-line */
+	public function setAttribute(string $key, $value): SpanInterface { return self::$instance; }
+
+	/** @phpstan-ignore-next-line */
+	public function setAttributes(iterable $attributes): SpanInterface { return self::$instance; }
+
+	/** @phpstan-ignore-next-line */
+	public function addEvent(string $name, iterable $attributes = [], ?int $timestamp = null): SpanInterface { return $this; }
+
+	/** @phpstan-ignore-next-line */
+	public function recordException(Throwable $exception, iterable $attributes = []): SpanInterface { return $this; }
+
+	public function updateName(string $name): SpanInterface { return $this; }
+
+	public function setStatus(string $code, ?string $description = null): SpanInterface { return $this; }
+
+	public function end(?int $endEpochNanos = null): void { }
+
+	public function activate(): ScopeInterface { return new DummyScopeInterface(); }
+
+	public function storeInContext(ContextInterface $context): ContextInterface { return new DummyContextInterface(); }
+
+}
+
+class Tracer {
+	/** @var Tracer $instance */
+	private static $instance = null;
+
+	/** @var OpenTelemetry\SDK\Trace\TracerProviderInterface $tracerProvider */
+	private $tracerProvider = null;
+
+	/** @var OpenTelemetry\API\Trace\TracerInterface $tracer */
+	private $tracer = null;
+
+	public function __construct() {
+		$OPENTELEMETRY_ENDPOINT = Config::get(Config::OPENTELEMETRY_ENDPOINT);
+
+		if ($OPENTELEMETRY_ENDPOINT) {
+			$transport = (new OtlpHttpTransportFactory())->create($OPENTELEMETRY_ENDPOINT, 'application/x-protobuf');
+			$exporter = new SpanExporter($transport);
+
+			$resource = ResourceInfoFactory::emptyResource()->merge(
+				ResourceInfo::create(Attributes::create(
+					[ResourceAttributes::SERVICE_NAME => Config::get(Config::OPENTELEMETRY_SERVICE)]
+				), ResourceAttributes::SCHEMA_URL),
+			);
+
+			$this->tracerProvider = TracerProvider::builder()
+				->addSpanProcessor(new SimpleSpanProcessor($exporter))
+				->setResource($resource)
+				->setSampler(new ParentBased(new AlwaysOnSampler()))
+				->build();
+
+			$this->tracer = $this->tracerProvider->getTracer('io.opentelemetry.contrib.php');
+
+			$context = TraceContextPropagator::getInstance()->extract(getallheaders());
+
+			$span = $this->tracer->spanBuilder($_SESSION['name'] ?? 'not logged in')
+				->setParent($context)
+				->setSpanKind(SpanKind::KIND_SERVER)
+				->setAttribute('php.request', json_encode($_REQUEST))
+				->setAttribute('php.server', json_encode($_SERVER))
+				->setAttribute('php.session', json_encode($_SESSION ?? []))
+				->startSpan();
+
+			$scope = $span->activate();
+
+			register_shutdown_function(function() use ($span, $scope) {
+				$span->end();
+				$scope->detach();
+				$this->tracerProvider->shutdown();
+			});
+		}
+	}
+
+	/**
+	 * @param string $name
+	 * @return OpenTelemetry\API\Trace\SpanInterface
+	 */
+	private function _start(string $name) {
+		if ($this->tracer != null) {
+			$span = $this->tracer
+				->spanBuilder($name)
+				->setSpanKind(SpanKind::KIND_SERVER)
+				->startSpan();
+
+			$span->activate();
+		} else {
+			$span = new DummySpanInterface();
+		}
+
+		return $span;
+	}
+
+	/**
+	 * @param string $name
+	 * @return OpenTelemetry\API\Trace\SpanInterface
+	 */
+	public static function start(string $name) {
+		return self::get_instance()->_start($name);
+	}
+
+	public static function get_instance() : Tracer {
+		if (self::$instance == null)
+			self::$instance = new self();
+
+		return self::$instance;
+	}
+}