From 1510539dd03e354745731b468308bac5bb0c324c Mon Sep 17 00:00:00 2001
From: Tobias Bachert <git@b-privat.de>
Date: Tue, 29 Nov 2022 23:57:11 +0100
Subject: [PATCH] Add PSR18 http client auto instrumentation (#78)

* Add PSR18 http client auto instrumentation
* Update for API changes
---
 examples/instrumentation/Psr18/request.php    |  38 +++++++
 .../Psr18/HeadersPropagator.php               |  24 ++++
 src/Instrumentation/Psr18/client_tracing.php  | 105 ++++++++++++++++++
 3 files changed, 167 insertions(+)
 create mode 100644 examples/instrumentation/Psr18/request.php
 create mode 100644 src/Instrumentation/Psr18/HeadersPropagator.php
 create mode 100644 src/Instrumentation/Psr18/client_tracing.php

diff --git a/examples/instrumentation/Psr18/request.php b/examples/instrumentation/Psr18/request.php
new file mode 100644
index 00000000..663198de
--- /dev/null
+++ b/examples/instrumentation/Psr18/request.php
@@ -0,0 +1,38 @@
+<?php
+
+declare(strict_types=1);
+
+use GuzzleHttp\Client;
+use GuzzleHttp\Psr7\Request;
+use OpenTelemetry\API\Common\Instrumentation;
+use OpenTelemetry\API\Trace\Propagation\TraceContextPropagator;
+use OpenTelemetry\SDK\Common\Time\ClockFactory;
+use OpenTelemetry\SDK\Resource\ResourceInfoFactory;
+use OpenTelemetry\SDK\Trace\Sampler\AlwaysOnSampler;
+use OpenTelemetry\SDK\Trace\SpanExporter\ConsoleSpanExporter;
+use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessor;
+use OpenTelemetry\SDK\Trace\TracerProvider;
+
+require_once dirname(__DIR__, 3) . '/vendor/autoload.php';
+require_once dirname(__DIR__, 3) . '/src/Instrumentation/Psr18/client_tracing.php';
+
+$tracerProvider =  new TracerProvider(
+    new BatchSpanProcessor(new ConsoleSpanExporter(), ClockFactory::getDefault()),
+    new AlwaysOnSampler(),
+    ResourceInfoFactory::emptyResource(),
+);
+
+$scope = Instrumentation\Configurator::create()
+    ->withTracerProvider($tracerProvider)
+    ->withPropagator(TraceContextPropagator::getInstance())
+    ->activate();
+
+try {
+    $client = new Client();
+
+    $response = $client->sendRequest(new Request('GET', 'https://postman-echo.com/get'));
+    echo json_encode(json_decode($response->getBody()->getContents()), JSON_PRETTY_PRINT), PHP_EOL;
+} finally {
+    $scope->detach();
+    $tracerProvider->shutdown();
+}
diff --git a/src/Instrumentation/Psr18/HeadersPropagator.php b/src/Instrumentation/Psr18/HeadersPropagator.php
new file mode 100644
index 00000000..25ba14da
--- /dev/null
+++ b/src/Instrumentation/Psr18/HeadersPropagator.php
@@ -0,0 +1,24 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Instrumentation\Psr18;
+
+use function assert;
+use OpenTelemetry\Context\Propagation\PropagationSetterInterface;
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * @internal
+ */
+enum HeadersPropagator implements PropagationSetterInterface
+{
+    case Instance;
+
+    public function set(&$carrier, string $key, string $value): void
+    {
+        assert($carrier instanceof RequestInterface);
+
+        $carrier = $carrier->withAddedHeader($key, $value);
+    }
+}
diff --git a/src/Instrumentation/Psr18/client_tracing.php b/src/Instrumentation/Psr18/client_tracing.php
new file mode 100644
index 00000000..7197767b
--- /dev/null
+++ b/src/Instrumentation/Psr18/client_tracing.php
@@ -0,0 +1,105 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Instrumentation\Psr18;
+
+use function get_cfg_var;
+use OpenTelemetry\API\Common\Instrumentation;
+use OpenTelemetry\API\Common\Instrumentation\CachedInstrumentation;
+use OpenTelemetry\API\Trace\Span;
+use OpenTelemetry\API\Trace\SpanKind;
+use OpenTelemetry\API\Trace\StatusCode;
+use OpenTelemetry\Context\Context;
+use function OpenTelemetry\Instrumentation\hook;
+use OpenTelemetry\SemConv\TraceAttributes;
+use Psr\Http\Client\ClientInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+use function sprintf;
+use function strtolower;
+use Throwable;
+
+hook(
+    ClientInterface::class,
+    'sendRequest',
+    static function (ClientInterface $client, array $params, string $class, string $function, ?string $filename, ?int $lineno): ?array {
+        $request = $params[0] ?? null;
+        if (!$request instanceof RequestInterface) {
+            Context::storage()->attach(Context::getCurrent());
+
+            return null;
+        }
+
+        static $instrumentation;
+        $instrumentation ??= new CachedInstrumentation('io.opentelemetry.contrib.php.psr18', schemaUrl: TraceAttributes::SCHEMA_URL);
+        $propagator = Instrumentation\Globals::propagator();
+        $parentContext = Context::getCurrent();
+
+        $spanBuilder = $instrumentation
+            ->tracer()
+            ->spanBuilder(sprintf('HTTP %s', $request->getMethod()))
+            ->setParent($parentContext)
+            ->setSpanKind(SpanKind::KIND_CLIENT)
+            ->setAttribute(TraceAttributes::HTTP_URL, (string) $request->getUri())
+            ->setAttribute(TraceAttributes::HTTP_METHOD, $request->getMethod())
+            ->setAttribute(TraceAttributes::HTTP_FLAVOR, $request->getProtocolVersion())
+            ->setAttribute(TraceAttributes::HTTP_USER_AGENT, $request->getHeaderLine('User-Agent'))
+            ->setAttribute(TraceAttributes::HTTP_REQUEST_CONTENT_LENGTH, $request->getHeaderLine('Content-Length'))
+            ->setAttribute(TraceAttributes::NET_PEER_NAME, $request->getUri()->getHost())
+            ->setAttribute(TraceAttributes::NET_PEER_PORT, $request->getUri()->getPort())
+            ->setAttribute(TraceAttributes::CODE_FUNCTION, $function)
+            ->setAttribute(TraceAttributes::CODE_NAMESPACE, $class)
+            ->setAttribute(TraceAttributes::CODE_FILEPATH, $filename)
+            ->setAttribute(TraceAttributes::CODE_LINENO, $lineno)
+        ;
+
+        foreach ($propagator->fields() as $field) {
+            $request = $request->withoutHeader($field);
+        }
+        foreach ((array) (get_cfg_var('otel.instrumentation.http.request_headers') ?: []) as $header) {
+            if ($request->hasHeader($header)) {
+                $spanBuilder->setAttribute(sprintf('http.request.header.%s', strtr(strtolower($header), ['-' => '_'])), $request->getHeader($header));
+            }
+        }
+
+        $span = $spanBuilder->startSpan();
+        $context = $span->storeInContext($parentContext);
+        $propagator->inject($request, HeadersPropagator::Instance, $context);
+
+        Context::storage()->attach($context);
+
+        return [$request];
+    },
+    static function (ClientInterface $client, array $params, ?ResponseInterface $response, ?Throwable $exception): void {
+        $scope = Context::storage()->scope();
+        $scope?->detach();
+
+        if (!$scope || $scope->context() === Context::getCurrent()) {
+            return;
+        }
+
+        $span = Span::fromContext($scope->context());
+
+        if ($response) {
+            $span->setAttribute(TraceAttributes::HTTP_STATUS_CODE, $response->getStatusCode());
+            $span->setAttribute(TraceAttributes::HTTP_FLAVOR, $response->getProtocolVersion());
+            $span->setAttribute(TraceAttributes::HTTP_RESPONSE_CONTENT_LENGTH, $response->getHeaderLine('Content-Length'));
+
+            foreach ((array) (get_cfg_var('otel.instrumentation.http.response_headers') ?: []) as $header) {
+                if ($response->hasHeader($header)) {
+                    $span->setAttribute(sprintf('http.response.header.%s', strtr(strtolower($header), ['-' => '_'])), $response->getHeader($header));
+                }
+            }
+            if ($response->getStatusCode() >= 400 && $response->getStatusCode() < 600) {
+                $span->setStatus(StatusCode::STATUS_ERROR);
+            }
+        }
+        if ($exception) {
+            $span->recordException($exception, [TraceAttributes::EXCEPTION_ESCAPED => true]);
+            $span->setStatus(StatusCode::STATUS_ERROR, $exception->getMessage());
+        }
+
+        $span->end();
+    },
+);