From 350177df3949bf884d38e133a3048d582a50efdb Mon Sep 17 00:00:00 2001
From: Andrew Dolgov <fox@fakecake.org>
Date: Fri, 20 Oct 2023 23:39:30 +0300
Subject: [PATCH] add placeholder instrumentation for public

---
 backend.php        |  8 ++------
 classes/tracer.php | 30 ++++++++++++++++++++++--------
 index.php          |  1 -
 public.php         | 11 ++++++++++-
 4 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/backend.php b/backend.php
index b4e118d62..c316bcc44 100644
--- a/backend.php
+++ b/backend.php
@@ -30,12 +30,6 @@
 	$op = (string)clean($op);
 	$method = (string)clean($method);
 
-	$span = Tracer::start(__FILE__);
-
-	register_shutdown_function(function() use ($span) {
-	 	$span->end();
-	});
-
 	startup_gettext();
 
 	$script_started = microtime(true);
@@ -44,6 +38,8 @@
 		return;
 	}
 
+	$span = OpenTelemetry\API\Trace\Span::getCurrent();
+
 	header("Content-Type: text/json; charset=utf-8");
 
 	if (Config::get(Config::SINGLE_USER_MODE)) {
diff --git a/classes/tracer.php b/classes/tracer.php
index e36b9f947..e8f6a0378 100644
--- a/classes/tracer.php
+++ b/classes/tracer.php
@@ -5,18 +5,23 @@ use OpenTelemetry\Contrib\Otlp\SpanExporter;
 use OpenTelemetry\SDK\Trace\SpanProcessor\SimpleSpanProcessor;
 use OpenTelemetry\SDK\Trace\TracerProvider;
 use OpenTelemetry\API\Trace\Propagation\TraceContextPropagator;
-use OpenTelemetry\API\Trace\Span;
+use OpenTelemetry\API\Trace\SpanKind;
 use OpenTelemetry\SDK\Trace\SpanExporter\InMemoryExporter;
 
 use OpenTelemetry\SDK\Resource\ResourceInfoFactory;
 use OpenTelemetry\SDK\Resource\ResourceInfo;
 use OpenTelemetry\SDK\Common\Attribute\Attributes;
 use OpenTelemetry\SemConv\ResourceAttributes;
+use OpenTelemetry\SDK\Trace\Sampler\AlwaysOnSampler;
+use OpenTelemetry\SDK\Trace\Sampler\ParentBased;
+
 
 class Tracer {
 	/** @var Tracer $instance */
 	private static $instance;
 
+	private $tracerProvider;
+
 	/** @var OpenTelemetry\API\Trace\TracerInterface $tracer */
 	private $tracer;
 
@@ -36,23 +41,29 @@ class Tracer {
 			), ResourceAttributes::SCHEMA_URL),
 		);
 
-		$tracerProvider =  new TracerProvider(new SimpleSpanProcessor($exporter), null, $resource);
+		$this->tracerProvider = TracerProvider::builder()
+			->addSpanProcessor(new SimpleSpanProcessor($exporter))
+			->setResource($resource)
+			->setSampler(new ParentBased(new AlwaysOnSampler()))
+			->build();
 
-		$this->tracer = $tracerProvider->getTracer('io.opentelemetry.contrib.php');
+		$this->tracer = $this->tracerProvider->getTracer('io.opentelemetry.contrib.php');
 
 		$context = TraceContextPropagator::getInstance()->extract(getallheaders());
+
 		$span = $this->tracer->spanBuilder('root')
 			->setParent($context)
-			->setAttribute('http.request', json_encode($_REQUEST))
+			->setSpanKind(SpanKind::KIND_SERVER)
+			->setAttribute('php.request', json_encode($_REQUEST))
+			->setAttribute('php.server', json_encode($_SERVER))
 			->startSpan();
 
 		$scope = $span->activate();
 
-		register_shutdown_function(function() use ($span, $tracerProvider, $scope) {
+		register_shutdown_function(function() use ($span, $scope) {
 			$span->end();
 			$scope->detach();
-
-			$tracerProvider->shutdown();
+			$this->tracerProvider->shutdown();
 		});
 	}
 
@@ -61,7 +72,10 @@ class Tracer {
 	 * @return OpenTelemetry\API\Trace\SpanInterface
 	 */
 	private function _start(string $name) {
-		$span = $this->tracer->spanBuilder($name)->startSpan();
+		$span = $this->tracer
+			->spanBuilder($name)
+			->setSpanKind(SpanKind::KIND_SERVER)
+			->startSpan();
 
 		$span->activate();
 
diff --git a/index.php b/index.php
index 276b79ec3..b7c039d7a 100644
--- a/index.php
+++ b/index.php
@@ -16,7 +16,6 @@
 
 	Config::sanity_check();
 
-
 	if (!init_plugins()) return;
 
 	UserHelper::login_sequence();
diff --git a/public.php b/public.php
index f44a94c01..6d9bc4b0c 100644
--- a/public.php
+++ b/public.php
@@ -14,6 +14,8 @@
 
 	if (!init_plugins()) return;
 
+	$span = OpenTelemetry\API\Trace\Span::getCurrent();
+
 	$method = (string)clean($_REQUEST["op"]);
 
 	// shortcut syntax for public (exposed) methods (?op=plugin--pmethod&...params)
@@ -39,27 +41,34 @@
 		user_error("Refusing to invoke method $method which starts with underscore.", E_USER_WARNING);
 		header("Content-Type: text/json");
 		print Errors::to_json(Errors::E_UNAUTHORIZED);
+		$span->setAttribute('error', Errors::E_UNAUTHORIZED);
 		return;
 	}
 
 	if (implements_interface($handler, "IHandler") && $handler->before($method)) {
+		$span->addEvent("construct/$method");
 		if ($method && method_exists($handler, $method)) {
 			$reflection = new ReflectionMethod($handler, $method);
 
 			if ($reflection->getNumberOfRequiredParameters() == 0) {
+				$span->addEvent("invoke/$method");
 				$handler->$method();
 			} else {
 				user_error("Refusing to invoke method $method which has required parameters.", E_USER_WARNING);
 				header("Content-Type: text/json");
 				print Errors::to_json(Errors::E_UNAUTHORIZED);
+				$span->setAttribute('error', Errors::E_UNAUTHORIZED);
 			}
 		} else if (method_exists($handler, 'index')) {
+			$span->addEvent("index");
 			$handler->index();
 		}
+		$span->addEvent("after/$method");
 		$handler->after();
 		return;
 	}
 
 	header("Content-Type: text/plain");
 	print Errors::to_json(Errors::E_UNKNOWN_METHOD);
-?>
+	$span->setAttribute('error', Errors::E_UNKNOWN_METHOD);
+