interfaces improvements (#36)

* add SpanProcessorInterface, rename ExporterInterface and TransportInterface, add getDescription on SampleInterface as described in specifications

* fix failing tests and improve Dockerfile for phan and test in order to use docker caching

.dockerignore

@@ -0,0 +1,2 @@
+/vendor
+/.git

composer.json

@@ -22,9 +22,8 @@
     },
     "autoload-dev": {
         "psr-4": {
-            "": "tests"
-        },
-        "classmap": ["tests"]
+            "Opentelemetry\\Tests\\": "test/"
+        }
     },
     "require-dev": {
         "phpunit/phpunit": "^7.5.16",

resources/Dockerfile.phan

@@ -5,7 +5,13 @@ mv composer.phar /usr/local/bin/composer && \
 chmod +x /usr/local/bin/composer && \
 pecl install ast-1.0.4 && \
 echo "extension=ast.so" >> /usr/local/etc/php/conf.d/docker-php-ext-ast.ini
-COPY . /usr/src/myapp
+
 WORKDIR /usr/src/myapp
+
+COPY ./composer.json ./
+COPY ./composer.lock ./
 RUN composer install
+
+COPY . ./
+
 ENTRYPOINT ["./vendor/bin/phan"]

resources/Dockerfile.test

@@ -5,7 +5,13 @@ mv composer.phar /usr/local/bin/composer && \
 chmod +x /usr/local/bin/composer && \
 pecl install ast-1.0.4 && \
 echo "extension=ast.so" >> /usr/local/etc/php/conf.d/docker-php-ext-ast.ini
-COPY . /usr/src/myapp
+
 WORKDIR /usr/src/myapp
+
+COPY ./composer.json ./
+COPY ./composer.lock ./
 RUN composer install
+
+COPY . ./
+
 ENTRYPOINT ["./vendor/phpunit/phpunit/phpunit", "--colors=always"]

src/Exporter/BasisExporter.php

@@ -4,10 +4,10 @@ declare(strict_types=1);
 
 namespace OpenTelemetry\Exporter;
 
-use OpenTelemetry\Exporter;
+use OpenTelemetry\Exporter\ExporterInterface;
 use OpenTelemetry\Tracing\Span;
 
-class BasisExporter extends Exporter
+class BasisExporter implements ExporterInterface
 {
     public function convertSpan(Span $span) : array
     {
@@ -20,4 +20,9 @@ class BasisExporter extends Exporter
             'body' => serialize($span),
         ];
     }
+
+    public function export(iterable $spans): int
+    {
+        return ExporterInterface::SUCCESS;
+    }
 }

src/Exporter/ExporterInterface.php

@@ -2,17 +2,16 @@
 
 declare(strict_types=1);
 
-namespace OpenTelemetry;
+namespace OpenTelemetry\Exporter;
 
 use OpenTelemetry\Tracing\Span;
-use OpenTelemetry\Tracing\Tracer;
 
 /**
  * A simple Exporter interface
  *
  * @package OpenTelemetry
  */
-interface Exporter
+interface ExporterInterface
 {
     /**
      * Possible return values as outlined in the OpenTelemetry spec

src/Exporter/ZipkinExporter.php

@@ -4,18 +4,18 @@ declare(strict_types=1);
 
 namespace OpenTelemetry\Exporter;
 
-use OpenTelemetry\Exporter;
+use OpenTelemetry\Exporter\ExporterInterface;
 use OpenTelemetry\Tracing\Span;
 
 /**
  * Class ZipkinExporter - implements the export interface for data transfer via Zipkin protocol
  * @package OpenTelemetry\Exporter
  */
-class ZipkinExporter implements Exporter
+class ZipkinExporter implements ExporterInterface
 {
 
     /**
-     * @var endpoint to send Spans to
+     * @var $endpoint array to send Spans to
      */
     private $endpoint;
 
@@ -35,6 +35,8 @@ class ZipkinExporter implements Exporter
         /* todo: format into JSON paylod for zipkin:
          * @see https://github.com/census-ecosystem/opencensus-php-exporter-zipkin/blob/master/src/ZipkinExporter.php#L143
          */
+
+        return ExporterInterface::SUCCESS;
     }
 
     /**
@@ -83,9 +85,9 @@ class ZipkinExporter implements Exporter
     /**
      * Gets the configured endpoint for the Zipkin exporter
      *
-     * @return endpoint
+     * @return array |null
      */
-    public function getEndpoint()
+    public function getEndpoint(): ?array
     {
         return $this->endpoint;
     }

src/SpanProcessorInterface.php

@@ -0,0 +1,26 @@
+<?php
+
+namespace OpenTelemetry;
+
+use OpenTelemetry\Tracing\Span;
+
+interface SpanProcessorInterface
+{
+    /**
+     * This method is called when a span is started.
+     * This method is called synchronously on the thread that started the span,
+     * therefore it should not block or throw exceptions.
+     */
+    public function onStart(Span $span): void;
+
+    /**
+     * This method  is called when a span is ended.
+     * This method is called synchronously on the execution thread,
+     * therefore it should not block or throw an exception.
+     */
+    public function onEnd(Span $span): void;
+
+    /* The spec mentions a shutdown() function. We don't see this as necessary;
+    * if an Exporter needs to clean up, it can use a destructor.
+    */
+}

src/Tracing/Sampler/AlwaysOffSampler.php

@@ -1,5 +1,6 @@
 <?php
 namespace OpenTelemetry\Tracing\Sampler;
+
 /**
  * This implementation of the SamplerInterface always returns false.
  * Example:
@@ -15,8 +16,13 @@ class AlwaysOffSampler implements SamplerInterface
      *
      * @return bool
      */
-    public function shouldSample()
+    public function shouldSample(): bool
     {
         return false;
     }
-} 
+
+    public function getDescription(): string
+    {
+        return self::class;
+    }
+}

src/Tracing/Sampler/AlwaysOnSampler.php

@@ -1,5 +1,6 @@
 <?php
 namespace OpenTelemetry\Tracing\Sampler;
+
 /**
  * This implementation of the SamplerInterface always returns true.
  * Example:
@@ -15,8 +16,13 @@ class AlwaysOnSampler implements SamplerInterface
      *
      * @return bool
      */
-    public function shouldSample()
+    public function shouldSample(): bool
     {
         return true;
     }
+
+    public function getDescription(): string
+    {
+        return self::class;
+    }
 } 

src/Tracing/Sampler/SamplerInterface.php

@@ -1,14 +1,25 @@
 <?php
 namespace OpenTelemetry\Tracing\Sampler;
+
 /**
  * This interface is used to organize sampling logic.
  */
 interface SamplerInterface
 {
+    const FLAG_SAMPLED = 1;
+
     /**
      * Returns true if we should sample the request.
      *
      * @return bool
      */
-    public function shouldSample();
+    public function shouldSample(): bool;
+
+    /**
+     * Returns the sampler name or short description with the configuration.
+     * This may be displayed on debug pages or in the logs.
+     * Example: "ProbabilitySampler{0.000100}"
+     * @return string
+     */
+    public function getDescription(): string;
 } 

src/Tracing/Span.php

@@ -19,6 +19,7 @@ class Span
 
     private $attributes = [];
     private $events = [];
+    private $link = [];
 
     // todo: missing span kind
     // https://github.com/open-telemetry/opentelemetry-specification/blob/master/specification/api-tracing.md#spankind
@@ -44,7 +45,7 @@ class Span
         $this->start = microtime(true);
         $this->statusCode = Status::OK;
         $this->statusDescription = null;
-        $this->link = addLinks();
+        $this->link = $this->addLinks();
     }
 
     public function getContext(): SpanContext
@@ -58,8 +59,9 @@ class Span
         return $this->parentSpanContext !== null ? clone $this->parentSpanContext : null;
     }
 
-    public function addLinks()
-    {;
+    public function addLinks(): array
+    {
+        return [];
     }
 
 

src/Tracing/SpanContext.php

@@ -28,6 +28,11 @@ class SpanContext
         return self::restore($traceId, bin2hex(random_bytes(8)));
     }
 
+    public static function restore(string $traceId, string $spanId)
+    {
+        return new self($traceId, $spanId, '', []);
+    }
+
     public function __construct(string $traceId, string $spanId, string $traceFlags, array $traceState)
     {
         $this->traceId = $traceId;

src/TransportInterface.php

@@ -4,7 +4,7 @@ declare(strict_types=1);
 
 namespace OpenTelemetry;
 
-interface Transport
+interface TransportInterface
 {
     public function write(array $data) : bool;
 }

tests/TracingTest.php

@@ -2,6 +2,8 @@
 
 declare(strict_types=1);
 
+namespace OpenTelemetry\Tests;
+
 use OpenTelemetry\Exporter\BasisExporter;
 use OpenTelemetry\Exporter\ZipkinExporter;
 use OpenTelemetry\Tracing\Builder;
@@ -10,6 +12,7 @@ use OpenTelemetry\Tracing\Status;
 use OpenTelemetry\Tracing\Tracer;
 use OpenTelemetry\Transport\TarantoolQueueTransport;
 use PHPUnit\Framework\TestCase;
+use ReflectionMethod;
 
 class TracingTest extends TestCase
 {
@@ -188,9 +191,7 @@ class TracingTest extends TestCase
     public function testBuilder()
     {
         $spanContext = SpanContext::generate();
-        $tracer = Builder::create()
-            ->setSpanContext($spanContext)
-            ->getTracer();
+        $tracer = new Tracer($spanContext);
 
         $this->assertInstanceOf(Tracer::class, $tracer);
         $this->assertEquals($tracer->getActiveSpan()->getContext(), $spanContext);
@@ -267,8 +268,12 @@ class TracingTest extends TestCase
         $event = $span->addEvent('validators.list', [ 'job' => 'stage.updateTime' ]);
         $span->end();
 
+        $method = new ReflectionMethod(ZipkinExporter::class, 'convertSpan');
+        $method->setAccessible(true);
+
         $exporter = new ZipkinExporter();
-        $row = $exporter->convertSpan($span);
+
+        $row = $method->invokeArgs($exporter, ['span' => $span]);
         $this->assertSame($row['name'], $span->getName());
 
         $this->assertSame($row['tags'], $span->getAttributes());

tests/unit/Tracing/Sampler/AlwaysOffSamplerTest.php

@@ -1,5 +1,6 @@
 <?php
-require __DIR__.'/../../../../vendor/autoload.php';
+namespace OpenTelemetry\Tests\Unit\Tracing\Sampler;
+
 use OpenTelemetry\Tracing\Sampler\AlwaysOffSampler;
 use PHPUnit\Framework\TestCase;
 class AlwaysOffSamplerTest extends TestCase

tests/unit/Tracing/Sampler/AlwaysOnSamplerTest.php

@@ -1,7 +1,10 @@
 <?php
-require __DIR__.'/../../../../vendor/autoload.php';
+
+namespace OpenTelemetry\Tests\Unit\Tracing\Sampler;
+
 use OpenTelemetry\Tracing\Sampler\AlwaysOnSampler;
 use PHPUnit\Framework\TestCase;
+
 class AlwaysOnTest extends TestCase
 {
     public function testAlwaysOnSampler()