Record exception with stack trace on log records (open-telemetry#410)

* Update LogWatcher.php

* add test coverage

* removes exception from context

Author: ol1s

src/Instrumentation/Laravel/src/Watchers/LogWatcher.php

@@ -10,6 +10,8 @@
 use OpenTelemetry\API\Instrumentation\CachedInstrumentation;
 use OpenTelemetry\API\Logs\LogRecord;
 use OpenTelemetry\API\Logs\Severity;
+use OpenTelemetry\SDK\Common\Exception\StackTraceFormatter;
+use Throwable;
 use TypeError;
 
 class LogWatcher extends Watcher
@@ -52,8 +54,21 @@ public function recordLog(MessageLogged $log): void
             // Should this fail, we should continue to emit the LogRecord.
         }
 
+        $contextToEncode = array_filter($log->context);
+
+        $exception = $this->getExceptionFromContext($log->context);
+
+        if ($exception !== null) {
+            unset($contextToEncode['exception']);
+        }
+
         $attributes = [
-            'context' => json_encode(array_filter($log->context)),
+            'context' => json_encode($contextToEncode),
+            ...$exception !== null ? [
+                'exception.type' => $exception::class,
+                'exception.message' => $exception->getMessage(),
+                'exception.stacktrace' => StackTraceFormatter::format($exception),
+            ] : [],
         ];
 
         $logger = $this->instrumentation->logger();
@@ -65,4 +80,16 @@ public function recordLog(MessageLogged $log): void
 
         $logger->emit($record);
     }
+
+    private function getExceptionFromContext(array $context): ?Throwable
+    {
+        if (
+            ! isset($context['exception']) ||
+            ! $context['exception'] instanceof Throwable
+        ) {
+            return null;
+        }
+
+        return $context['exception'];
+    }
 }

src/Instrumentation/Laravel/tests/Integration/LaravelInstrumentationTest.php

@@ -4,6 +4,7 @@
 
 namespace OpenTelemetry\Tests\Contrib\Instrumentation\Laravel\Integration;
 
+use Exception;
 use Illuminate\Routing\Router;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Http;
@@ -106,6 +107,16 @@ public function test_route_span_name_if_not_found(): void
         $this->assertSame('GET', $span->getName());
     }
 
+    public function test_records_exception_in_logs(): void
+    {
+        $this->router()->get('/exception', fn () => throw new Exception('Test exception'));
+        $this->call('GET', '/exception');
+        $logRecord = $this->storage[0];
+        $this->assertEquals(Exception::class, $logRecord->getAttributes()->get(TraceAttributes::EXCEPTION_TYPE));
+        $this->assertEquals('Test exception', $logRecord->getAttributes()->get(TraceAttributes::EXCEPTION_MESSAGE));
+        $this->assertNotNull($logRecord->getAttributes()->get(TraceAttributes::EXCEPTION_STACKTRACE));
+    }
+
     private function router(): Router
     {
         /** @psalm-suppress PossiblyNullReference */