Added facades for hosts functions

.gitignore

@@ -5,3 +5,4 @@
 vendor
 composer.lock
 jaeger-client-php.iml
+phpunit.xml

build/.gitignore

@@ -0,0 +1,2 @@
+*
+!.gitignore

composer.json

@@ -19,7 +19,7 @@
     },
     "autoload": {
         "psr-4": {
-            "Jaeger\\": "src\\Jaeger"
+            "Jaeger\\": "src/Jaeger/"
         },
         "files": [
             "./src/Jaeger/Constants.php"

phpunit.xml.dist

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="vendor/phpunit/phpunit/phpunit.xsd"
+         bootstrap="vendor/autoload.php"
+         colors="true"
+>
+    <filter>
+        <whitelist>
+            <directory suffix=".php">src/Jaeger</directory>
+            <exclude>
+                <directory suffix="Interface.php">src/</directory>
+                <file>src/Jaeger/Constants.php</file>
+                <file>src/Jaeger/Thrift/Agent/AgentIf.php</file>
+                <file>src/Jaeger/Thrift/Agent/AggregationValidatorIf.php</file>
+                <file>src/Jaeger/Thrift/Agent/BaggageRestrictionManagerIf.php</file>
+                <file>src/Jaeger/Thrift/Agent/DependencyIf.php</file>
+                <file>src/Jaeger/Thrift/Agent/SamplingManagerIf.php</file>
+                <file>src/Jaeger/Thrift/CollectorIf.php</file>
+                <file>src/Jaeger/Thrift/Crossdock/TracedServiceIf.php</file>
+            </exclude>
+        </whitelist>
+    </filter>
+
+    <testsuites>
+        <testsuite name="Jaeger Test Suite">
+            <directory suffix=".php">tests/Jaeger</directory>
+        </testsuite>
+    </testsuites>
+
+    <php>
+        <ini name="date.timezone" value="UTC"/>
+        <ini name="display_errors" value="on"/>
+        <ini name="display_startup_errors" value="on"/>
+    </php>
+
+    <logging>
+        <log
+            type="coverage-text"
+            target="php://stdout"
+            lowUpperBound="60"
+            highLowerBound="90"/>
+
+        <log
+            type="coverage-clover"
+            target="build/coverage.xml"/>
+    </logging>
+</phpunit>

src/Jaeger/Tracer.php

@@ -41,12 +41,11 @@ class Tracer implements OTTracer
      */
     private $sampler;
 
+    /**
+     * @var string
+     */
     private $ipAddress;
 
-    private $metricsFactory;
-
-    private $metrics;
-
     /**
      * @var string
      */
@@ -108,8 +107,6 @@ public function __construct(
         $this->logger = $logger ?? new NullLogger();
         $this->scopeManager = $scopeManager ?? new ScopeManager();
 
-        $this->ipAddress = gethostbyname(gethostname());
-
         $this->debugIdHeader = $debugIdHeader;
 
         $this->codecs = [
@@ -136,10 +133,10 @@ public function __construct(
             $this->tags = array_merge($this->tags, $tags);
         }
 
-        $hostname = gethostname();
-        if ($hostname === FALSE) {
-            $this->logger->error('Unable to determine host name');
-        } else {
+        $hostname = $this->getHostname();
+        $this->ipAddress = $this->getHostByName($hostname);
+
+        if (empty($hostname) != false) {
             $this->tags[JAEGER_HOSTNAME_TAG_KEY] = $hostname;
         }
     }
@@ -342,6 +339,34 @@ private function randomId(): string
         return (string) random_int(0, PHP_INT_MAX);
     }
 
+    /**
+     * The facade to get the host name.
+     *
+     * @return string
+     */
+    protected function getHostName()
+    {
+        return gethostname();
+    }
+
+    /**
+     * The facade to get IPv4 address corresponding to a given Internet host name.
+     *
+     * NOTE: DNS Resolution may take too long, and during this time your script is NOT being executed.
+     *
+     * @param string|null $hostname
+     * @return string
+     */
+    protected function getHostByName($hostname)
+    {
+        if (empty($hostname)) {
+            $this->logger->error('Unable to determine host name');
+            return '127.0.0.1';
+        }
+
+        return gethostbyname($hostname);
+    }
+
     /**
      * @param SamplerInterface $sampler
      * @return $this

tests/Jaeger/TracerTest.php

@@ -126,4 +126,23 @@ function testFlush()
 
         $this->tracer->flush();
     }
+
+    /** @test */
+    public function shouldHandleEmptyHostName()
+    {
+        $tracer = new \ReflectionClass(Tracer::class);
+
+        $getHostByName = $tracer->getMethod('getHostByName');
+        $getHostByName->setAccessible(true);
+
+        $stub = $this->getMockBuilder(Tracer::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+
+        $logger = $tracer->getProperty('logger');
+        $logger->setAccessible(true);
+        $logger->setValue($stub, $this->logger);
+
+        $this->assertEquals('127.0.0.1', $getHostByName->invokeArgs($stub, [null]));
+    }
 }