Remove sampler factory (#72)

* Remove SamplerFactory

* Remove documentation mentioning the SamplerFactory

Author: chingor13

src/Trace/Sampler/SamplerFactory.php

@@ -19,7 +19,7 @@
 
 use OpenCensus\Core\Scope;
 use OpenCensus\Trace\Span;
-use OpenCensus\Trace\Sampler\SamplerFactory;
+use OpenCensus\Trace\Sampler\AlwaysSampleSampler;
 use OpenCensus\Trace\Sampler\SamplerInterface;
 use OpenCensus\Trace\Exporter\ExporterInterface;
 use OpenCensus\Trace\Propagator\PropagatorInterface;
@@ -57,19 +57,7 @@
  * The above uses a query-per-second sampler at 0.1 requests/second. The implementation
  * requires a PSR-6 cache. See {@see OpenCensus\Trace\Sampler\QpsSampler} for more information.
  * You may provide your own implementation of {@see OpenCensus\Trace\Sampler\SamplerInterface}
- * or use one of the provided. You may provide a configuration array for the sampler instead. See
- * {@see OpenCensus\Trace\Sampler\SamplerFactory::build()} for builder options:
- *
- * ```
- * // $cache is a PSR-6 cache implementation
- * Tracer::start($reporter, [
- *     'sampler' => [
- *         'type' => 'qps',
- *         'rate' => 0.1,
- *         'cache' => $cache
- *     ]
- * ]);
- * ```
+ * or use one of the provided.
  *
  * To trace code, you can use static {@see OpenCensus\Trace\Tracer::inSpan()} helper function:
  *
@@ -120,8 +108,8 @@ class Tracer
      *      Configuration options. See
      *      {@see OpenCensus\Trace\Span::__construct()} for the other available options.
      *
-     *      @type SamplerInterface|array $sampler Sampler or sampler factory build arguments. See
-     *          {@see OpenCensus\Trace\Sampler\SamplerFactory::build()} for the available options.
+     *      @type SamplerInterface $sampler Sampler that defines the sampling rules.
+     *            **Defaults to** a new `AlwaysSampleSampler`.
      *      @type PropagatorInterface $propagator SpanContext propagator. **Defaults to**
      *            a new `HttpHeaderPropagator` instance
      *      @type array $headers Optional array of headers to use in place of $_SERVER
@@ -130,13 +118,11 @@ class Tracer
      */
     public static function start(ExporterInterface $reporter, array $options = [])
     {
-        $samplerOptions = array_key_exists('sampler', $options) ? $options['sampler'] : [];
+        $sampler = array_key_exists('sampler', $options)
+            ? $options['sampler']
+            : new AlwaysSampleSampler();
         unset($options['sampler']);
 
-        $sampler = ($samplerOptions instanceof SamplerInterface)
-            ? $samplerOptions
-            : SamplerFactory::build($samplerOptions);
-
         $propagator = array_key_exists('propagator', $options)
             ? $options['propagator']
             : new HttpHeaderPropagator();

src/Trace/Tracer.php

@@ -18,6 +18,8 @@
 namespace OpenCensus\Tests\Unit\Trace;
 
 use OpenCensus\Trace\Exporter\ExporterInterface;
+use OpenCensus\Trace\Sampler\AlwaysSampleSampler;
+use OpenCensus\Trace\Sampler\NeverSampleSampler;
 use OpenCensus\Trace\Tracer;
 use OpenCensus\Trace\Tracer\NullTracer;
 
@@ -36,7 +38,7 @@ public function setUp()
     public function testForceDisabled()
     {
         $rt = Tracer::start($this->reporter->reveal(), [
-            'sampler' => ['type' => 'disabled']
+            'sampler' => new NeverSampleSampler()
         ]);
         $tracer = $rt->tracer();
 
@@ -47,7 +49,7 @@ public function testForceDisabled()
     public function testForceEnabled()
     {
         $rt = Tracer::start($this->reporter->reveal(), [
-            'sampler' => ['type' => 'enabled']
+            'sampler' => new AlwaysSampleSampler()
         ]);
         $tracer = $rt->tracer();