feat(laravel): adds laravel instrumentation.

composer.json

@@ -27,13 +27,15 @@
     },
     "require-dev": {
         "guzzlehttp/psr7": "^1.6",
+        "illuminate/http": "^7.20",
+        "illuminate/routing": "^7.20",
         "jcchavezs/httptest": "~0.2",
+        "middlewares/fast-route": "^1.2.1",
+        "middlewares/request-handler": "^1.4.0",
         "phpstan/phpstan": "~0.12.28",
         "phpunit/phpunit": "~7.5.20",
         "psr/http-client": "^1.0",
         "psr/http-server-middleware": "^1.0",
-        "middlewares/fast-route": "^1.2.1",
-        "middlewares/request-handler": "^1.4.0",
         "squizlabs/php_codesniffer": "3.*"
     },
     "config": {
@@ -76,4 +78,4 @@
             "dev-master": "2.0.x-dev"
         }
     }
-}
+}

src/Zipkin/Instrumentation/Laravel/DefaultParser.php

@@ -0,0 +1,43 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zipkin\Instrumentation\Laravel;
+
+use Zipkin\Tags;
+use Zipkin\SpanCustomizer;
+use Zipkin\Propagation\TraceContext;
+use Zipkin\Instrumentation\Http\Server\Parser;
+use Illuminate\Http\Response;
+use Illuminate\Http\Request;
+
+class DefaultParser implements Parser
+{
+    /**
+     * @param Request $request
+     */
+    public function spanName($request): string
+    {
+        return $request->route()->getName();
+    }
+
+    /**
+     * @param Request $request
+     */
+    public function request($request, TraceContext $context, SpanCustomizer $span): void
+    {
+        $span->tag(Tags\HTTP_METHOD, $request->method());
+        $span->tag(Tags\HTTP_PATH, $request->path());
+    }
+
+    /**
+     * @param Response $response
+     */
+    public function response($response, TraceContext $context, SpanCustomizer $span): void
+    {
+        $span->tag(Tags\HTTP_STATUS_CODE, (string) $response->getStatusCode());
+        if ($response->getStatusCode() > 399) {
+            $span->tag(Tags\ERROR, (string) $response->getStatusCode());
+        }
+    }
+}

src/Zipkin/Instrumentation/Laravel/Middleware.php

@@ -0,0 +1,107 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zipkin\Instrumentation\Laravel;
+
+use Zipkin\Tracing;
+use Zipkin\Tracer;
+use Zipkin\SpanCustomizerShield;
+use Zipkin\Span;
+use Zipkin\Propagation\TraceContext;
+use Zipkin\Propagation\SamplingFlags;
+use Zipkin\Propagation\DefaultSamplingFlags;
+use Zipkin\Kind;
+use Zipkin\Instrumentation\Laravel\Propagation\RequestHeaders;
+use Zipkin\Instrumentation\Http\Server\HttpServerTracing;
+use Throwable;
+use Illuminate\Http\Request;
+use Closure;
+
+class Middleware
+{
+    /**
+     * @var Tracer
+     */
+    private $tracer;
+
+    /**
+     * @var callable(array):?bool
+     */
+    private $extractor;
+
+    /**
+     * @var Parser
+     */
+    private $parser;
+
+    /**
+     * @var (callable(Request):?bool)|null
+     */
+    private $requestSampler;
+
+    public function __construct(HttpServerTracing $tracing)
+    {
+        $this->tracer = $tracing->getTracing()->getTracer();
+        $this->extractor = $tracing->getTracing()->getPropagation()->getExtractor(new RequestHeaders());
+        $this->parser = $tracing->getParser();
+        $this->requestSampler = $tracing->getRequestSampler();
+    }
+
+    public static function createFromTracing(Tracing $tracing): self
+    {
+        return new self(new HttpServerTracing($tracing, new DefaultParser));
+    }
+
+    public function handle(Request $request, Closure $next)
+    {
+        $extractedContext = ($this->extractor)($request);
+
+        $span = $this->nextSpan($extractedContext, $request);
+        $scopeCloser = $this->tracer->openScope($span);
+
+        if ($span->isNoop()) {
+            try {
+                return $next($request);
+            } finally {
+                $span->finish();
+                $scopeCloser();
+            }
+        }
+
+        $span->setKind(Kind\SERVER);
+        $spanCustomizer = new SpanCustomizerShield($span);
+        $span->setName($this->parser->spanName($request));
+        $this->parser->request($request, $span->getContext(), $spanCustomizer);
+
+        try {
+            $response = $next($request);
+            $this->parser->response($response, $span->getContext(), $spanCustomizer);
+            return $response;
+        } catch (Throwable $e) {
+            $span->setError($e);
+            throw $e;
+        } finally {
+            $span->finish();
+            $scopeCloser();
+        }
+    }
+
+    private function nextSpan(?SamplingFlags $extractedContext, Request $request): Span
+    {
+        if ($extractedContext instanceof TraceContext) {
+            return $this->tracer->joinSpan($extractedContext);
+        }
+
+        $extractedContext = $extractedContext ?? DefaultSamplingFlags::createAsEmpty();
+        if ($this->requestSampler === null) {
+            return $this->tracer->nextSpan($extractedContext);
+        }
+
+        return $this->tracer->nextSpanWithSampler(
+            $this->requestSampler,
+            [$request],
+            $extractedContext
+        );
+    }
+}

src/Zipkin/Instrumentation/Laravel/Propagation/RequestHeaders.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Zipkin\Instrumentation\Laravel\Propagation;
+
+use Zipkin\Propagation\Getter;
+use Illuminate\Http\Request;
+
+final class RequestHeaders implements Getter
+{
+    /**
+     * {@inheritdoc}
+     *
+     * @param Request $carrier
+     */
+    public function get($carrier, string $key): ?string
+    {
+        return $carrier->hasHeader($key) ? $carrier->header($key)[0] : null;
+    }
+}