Implement TracerFactory

Signed-off-by: Juraci Paixão Kröhling <juraci@kroehling.de>

build.gradle

@@ -23,7 +23,7 @@ ext.apacheThriftVersion = getProperty('apacheThriftVersion','0.11.0')
 ext.jerseyVersion = getProperty('jerseyVersion','2.22.2')
 ext.slf4jVersion = getProperty('slf4jVersion','1.7.25')
 ext.gsonVersion = getProperty('gsonVersion','2.8.2')
-ext.tracerResolverVersion = getProperty('tracerResolverVersion','0.1.4')
+ext.tracerResolverVersion = getProperty('tracerResolverVersion','0.1.5')
 ext.micrometerVersion = getProperty('micrometerVersion','1.0.0')
 ext.okhttpVersion = getProperty('okhttpVersion','3.9.0')
 

jaeger-tracerresolver/README.md

@@ -1,8 +1,7 @@
 # Jaeger Tracer Resolver
 
-This module provides a Jaeger implementation for the [TracerResolver](https://github.com/opentracing-contrib/java-tracerresolver). This mechanism provides a vendor neutral approach for obtaining a `Tracer` using the JDK
-`ServiceLoader`.
-
+This module provides a Jaeger implementation for the [TracerResolver](https://github.com/opentracing-contrib/java-tracerresolver).
+This mechanism provides a vendor neutral approach for obtaining a `Tracer` using the JDK `ServiceLoader`.
 
 ## Maven Dependency
 ```xml

jaeger-tracerresolver/src/main/java/io/jaegertracing/tracerresolver/internal/JaegerTracerFactory.java

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2018, The Jaeger Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+
+package io.jaegertracing.tracerresolver.internal;
+
+import io.jaegertracing.Configuration;
+import io.jaegertracing.internal.JaegerTracer;
+import io.opentracing.Tracer;
+import io.opentracing.contrib.tracerresolver.TracerFactory;
+
+public class JaegerTracerFactory implements TracerFactory {
+    @Override
+    public Tracer getTracer() {
+        return getJaegerTracer();
+    }
+
+    public JaegerTracer getJaegerTracer() {
+        return Configuration.fromEnv().getTracer();
+    }
+}

jaeger-tracerresolver/src/main/java/io/jaegertracing/tracerresolver/internal/JaegerTracerResolver.java

@@ -14,15 +14,14 @@
 
 package io.jaegertracing.tracerresolver.internal;
 
-import io.jaegertracing.Configuration;
 import io.jaegertracing.internal.JaegerTracer;
 import io.opentracing.contrib.tracerresolver.TracerResolver;
 
 public class JaegerTracerResolver extends TracerResolver {
 
   @Override
   protected JaegerTracer resolve() {
-    return Configuration.fromEnv().getTracer();
+    return new JaegerTracerFactory().getJaegerTracer();
   }
 
 }

jaeger-tracerresolver/src/main/resources/META-INF/services/io.opentracing.contrib.tracerresolver.TracerFactory

@@ -0,0 +1 @@
+io.jaegertracing.tracerresolver.internal.JaegerTracerFactory

jaeger-tracerresolver/src/test/java/io/jaegertracing/tracerresolver/internal/JaegerTracerResolverTest.java

@@ -21,11 +21,14 @@
 import io.jaegertracing.Configuration;
 import io.jaegertracing.internal.JaegerTracer;
 import io.opentracing.Tracer;
+import io.opentracing.contrib.tracerresolver.TracerFactory;
 import io.opentracing.contrib.tracerresolver.TracerResolver;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
 
+import java.util.ServiceLoader;
+
 public class JaegerTracerResolverTest {
 
   @Before
@@ -48,4 +51,12 @@ public void testResolveTracerDefault() {
     assertTrue(tracer instanceof JaegerTracer);
   }
 
+  @Test
+  public void canFindTracerFactory() {
+    System.setProperty(Configuration.JAEGER_SERVICE_NAME, "canFindTracerFactory");
+    Tracer tracer = ServiceLoader.load(TracerFactory.class).iterator().next().getTracer();
+    assertNotNull(tracer);
+    assertTrue(tracer instanceof JaegerTracer);
+  }
+
 }