adding batch span processor builder (#1046)

examples/sdk_builder.php

@@ -18,7 +18,7 @@ use OpenTelemetry\SDK\Sdk;
 use OpenTelemetry\SDK\Trace\Sampler\AlwaysOnSampler;
 use OpenTelemetry\SDK\Trace\Sampler\ParentBased;
 use OpenTelemetry\SDK\Trace\SpanExporter\InMemoryExporter;
-use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessorBuilder;
+use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessor;
 use OpenTelemetry\SDK\Trace\TracerProvider;
 
 require __DIR__ . '/../vendor/autoload.php';
@@ -50,7 +50,7 @@ $loggerProvider = LoggerProvider::builder()
 
 $tracerProvider = TracerProvider::builder()
     ->addSpanProcessor(
-        (new BatchSpanProcessorBuilder($spanExporter))
+        BatchSpanProcessor::builder($spanExporter)
             ->setMeterProvider($meterProvider)
             ->build()
     )

src/SDK/Trace/ExporterFactory.php

@@ -18,7 +18,6 @@ class ExporterFactory
     public function create(): ?SpanExporterInterface
     {
         $exporters = Configuration::getList(Variables::OTEL_TRACES_EXPORTER);
-        //TODO "The SDK MAY accept a comma-separated list to enable setting multiple exporters"
         if (1 !== count($exporters)) {
             throw new InvalidArgumentException(sprintf('Configuration %s requires exactly 1 exporter', Variables::OTEL_TRACES_EXPORTER));
         }

src/SDK/Trace/SpanProcessor/BatchSpanProcessor.php

@@ -198,6 +198,11 @@ class BatchSpanProcessor implements SpanProcessorInterface
         return $this->flush(__FUNCTION__, $cancellation);
     }
 
+    public static function builder(SpanExporterInterface $exporter): BatchSpanProcessorBuilder
+    {
+        return new BatchSpanProcessorBuilder($exporter);
+    }
+
     private function flush(?string $flushMethod = null, ?CancellationInterface $cancellation = null): bool
     {
         if ($flushMethod !== null) {

tests/Unit/SDK/Trace/SpanProcessor/BatchSpanProcessorBuilderTest.php

@@ -0,0 +1,33 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OpenTelemetry\Tests\Unit\SDK\Trace\SpanProcessor;
+
+use OpenTelemetry\API\Metrics\MeterInterface;
+use OpenTelemetry\SDK\Metrics\MeterProviderInterface;
+use OpenTelemetry\SDK\Trace\SpanExporterInterface;
+use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessor;
+use PHPUnit\Framework\TestCase;
+
+/**
+ * @covers \OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessorBuilder
+ */
+class BatchSpanProcessorBuilderTest extends TestCase
+{
+    public function test_build(): void
+    {
+        $exporter = $this->createMock(SpanExporterInterface::class);
+        $meterProvider = $this->createMock(MeterProviderInterface::class);
+        $meter = $this->createMock(MeterInterface::class);
+        $meterProvider->expects($this->once())->method('getMeter')->willReturn($meter);
+        $processor = BatchSpanProcessor::builder($exporter)
+            ->setMeterProvider($meterProvider)
+            ->build();
+        $reflection = new \ReflectionClass($processor);
+        $property = $reflection->getProperty('exporter');
+        $property->setAccessible(true);
+
+        $this->assertSame($exporter, $property->getValue($processor));
+    }
+}

tests/Unit/SDK/Trace/SpanProcessor/BatchSpanProcessorTest.php

@@ -27,6 +27,7 @@ use OpenTelemetry\SDK\Trace\ReadWriteSpanInterface;
 use OpenTelemetry\SDK\Trace\SpanDataInterface;
 use OpenTelemetry\SDK\Trace\SpanExporterInterface;
 use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessor;
+use OpenTelemetry\SDK\Trace\SpanProcessor\BatchSpanProcessorBuilder;
 use OpenTelemetry\SDK\Trace\SpanProcessorInterface;
 use OpenTelemetry\Tests\Unit\SDK\Util\TestClock;
 use Psr\Log\LoggerInterface;
@@ -542,6 +543,12 @@ class BatchSpanProcessorTest extends MockeryTestCase
         new BatchSpanProcessor($exporter, $this->testClock, 2, 5000, 30000, 3);
     }
 
+    public function test_get_builder(): void
+    {
+        $exporter = $this->createMock(SpanExporterInterface::class);
+        $this->assertInstanceOf(BatchSpanProcessorBuilder::class, BatchSpanProcessor::builder($exporter));
+    }
+
     private function createSampledSpanMock()
     {
         $spanContext = $this->createConfiguredMock(API\SpanContextInterface::class, ['isSampled' => true]);