Added silencer

spec/BalancerBuilderSpec.php

@@ -19,6 +19,7 @@ function it_can_build_the_balancer(Monitor $monitor, LoggerInterface $logger)
     {
         $this->withLogger($logger)->shouldReturnAnInstanceOf(BalancerBuilder::class);
         $this->withMonitor($monitor, "foo")->shouldReturnAnInstanceOf(BalancerBuilder::class);
+        $this->withoutExceptions()->shouldReturnAnInstanceOf(BalancerBuilder::class);
         $this->create([
             "feature_1" => ["foo" => 50, "off" => 50],
             "feature_2" => ["bar" => 20, "rab" => 40, "arb" => 40]

spec/Decorator/ExceptionSilencerDecoratorSpec.php

@@ -0,0 +1,29 @@
+<?php
+
+namespace spec\Cmp\FeatureBalancer\Decorator;
+
+use Cmp\FeatureBalancer\BalancerInterface;
+use Cmp\FeatureBalancer\Exception\OutOfBoundsException;
+use PhpSpec\ObjectBehavior;
+use Psr\Log\LoggerInterface;
+
+class ExceptionSilencerDecoratorSpec extends ObjectBehavior
+{
+    function let(BalancerInterface $balancer, LoggerInterface $logger)
+    {
+        $this->beConstructedWith($balancer, $logger);
+    }
+
+    function it_silences_exceptions(BalancerInterface $balancer, LoggerInterface $logger)
+    {
+        $exception = new OutOfBoundsException("feature foo is not set");
+        $balancer->get("foo", 123456)->willThrow($exception);
+
+        $this->get("foo", 123456)->shouldBe("");
+
+        $logger->error("Exception thrown balancing feature 'foo'", [
+            "feature"   => "foo",
+            "exception" => $exception,
+        ])->shouldHaveBeenCalled();
+    }
+}

src/BalancerBuilder.php

@@ -3,6 +3,7 @@
 namespace Cmp\FeatureBalancer;
 
 use Cmp\FeatureBalancer\Config\Identifier;
+use Cmp\FeatureBalancer\Decorator\ExceptionSilencerDecorator;
 use Cmp\FeatureBalancer\Decorator\LoggerDecorator;
 use Cmp\FeatureBalancer\Decorator\MonitoringDecorator;
 use Cmp\Monitoring\Monitor;
@@ -31,6 +32,11 @@ class BalancerBuilder
      */
     private $logLevel;
 
+    /**
+     * @var bool
+     */
+    private $exceptions = true;
+
     /**
      * @param array $config
      *
@@ -49,6 +55,10 @@ public function create(array $config = [])
             $balancer = new LoggerDecorator($balancer, $this->logger, $this->logLevel);
         }
 
+        if (!$this->exceptions) {
+            $balancer = new ExceptionSilencerDecorator($balancer, $this->logger);
+        }
+
         return $balancer;
     }
 
@@ -80,6 +90,16 @@ public function withLogger(LoggerInterface $logger, $logLevel = LogLevel::INFO)
         return $this;
     }
 
+    /**
+     * @return $this
+     */
+    public function withoutExceptions()
+    {
+        $this->exceptions = false;
+
+        return $this;
+    }
+
     /**
      * Add the features to the balancer
      *

src/Decorator/ExceptionSilencerDecorator.php

@@ -0,0 +1,43 @@
+<?php
+
+namespace Cmp\FeatureBalancer\Decorator;
+
+use Cmp\FeatureBalancer\BalancerInterface;
+use Cmp\FeatureBalancer\Exception\BalancerException;
+use Psr\Log\LoggerInterface;
+use Psr\Log\NullLogger;
+
+class ExceptionSilencerDecorator extends BalancerDecorator implements BalancerInterface
+{
+    /**
+     * @var LoggerInterface
+     */
+    private $logger;
+
+    /**
+     * @param BalancerInterface    $balancer
+     * @param LoggerInterface|null $logger
+     */
+    public function __construct(BalancerInterface $balancer, LoggerInterface $logger = null)
+    {
+        parent::__construct($balancer);
+        $this->logger = $logger ?: new NullLogger();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function get($feature, $seed = null)
+    {
+        try {
+            return $this->balancer->get($feature, $seed);
+        } catch (BalancerException $exception) {
+            $this->logger->error("Exception thrown balancing feature '$feature'", [
+                "feature"   => $feature,
+                "exception" => $exception,
+            ]);
+        }
+
+        return "";
+    }
+}