Fixing issue with the tracer factory (decorators aren't loaded)

dd-trace/src/main/java/com/datadoghq/trace/resolver/DDTracerFactory.java

@@ -1,6 +1,7 @@
 package com.datadoghq.trace.resolver;
 
 import com.datadoghq.trace.DDTracer;
+import com.datadoghq.trace.integration.DDSpanContextDecorator;
 import com.datadoghq.trace.sampling.AbstractSampler;
 import com.datadoghq.trace.sampling.AllSampler;
 import com.datadoghq.trace.sampling.RateSampler;
@@ -9,6 +10,8 @@ import com.datadoghq.trace.writer.DDAgentWriter;
 import com.datadoghq.trace.writer.DDApi;
 import com.datadoghq.trace.writer.LoggingWriter;
 import com.datadoghq.trace.writer.Writer;
+
+import java.util.List;
 import java.util.Map;
 import java.util.regex.Pattern;
 import lombok.extern.slf4j.Slf4j;
@@ -99,6 +102,12 @@ public class DDTracerFactory {
       tracer = DDTracerFactory.create(tracerConfig);
     }
 
+    //Create decorators from resource files
+    final List<DDSpanContextDecorator> decorators = DDDecoratorsFactory.createFromResources();
+    for (final DDSpanContextDecorator decorator : decorators) {
+      tracer.addDecorator(decorator);
+    }
+
     return tracer;
   }
 }

dd-trace/src/main/java/com/datadoghq/trace/resolver/DDTracerResolver.java

@@ -23,11 +23,7 @@ public class DDTracerResolver extends TracerResolver {
     //Create tracer from resource files
     tracer = DDTracerFactory.createFromConfigurationFile();
 
-    //Create decorators from resource files
-    final List<DDSpanContextDecorator> decorators = DDDecoratorsFactory.createFromResources();
-    for (final DDSpanContextDecorator decorator : decorators) {
-      tracer.addDecorator(decorator);
-    }
+
 
     return tracer;
   }

dd-trace/src/test/groovy/com/datadoghq/trace/SpanFactory.groovy

@@ -17,4 +17,21 @@ class SpanFactory {
       null)
     return new DDSpan(timestampMicro, context)
   }
+
+  static newSpanTracer(DDTracer tracer) {
+    def context = new DDSpanContext(
+      1L,
+      1L,
+      0L,
+      "fakeService",
+      "fakeOperation",
+      "fakeResource",
+      Collections.emptyMap(),
+      false,
+      "fakeType",
+      Collections.emptyMap(),
+      null,
+      tracer)
+    return new DDSpan(0, context)
+  }
 }

dd-trace/src/test/groovy/com/datadoghq/trace/integration/SpanDecoratorTest.groovy

@@ -0,0 +1,36 @@
+package com.datadoghq.trace.integration
+
+import com.datadoghq.trace.DDSpanContext
+import com.datadoghq.trace.DDTracer
+import com.datadoghq.trace.SpanFactory
+import io.opentracing.tag.StringTag
+import spock.lang.Specification
+
+class SpanDecoratorTest extends Specification {
+
+  def "adding span personalisation using Decorators"() {
+    setup:
+    def tracer = new DDTracer()
+    def decorator = new DDSpanContextDecorator() {
+
+      @Override
+      boolean afterSetTag(DDSpanContext context, String tag, Object value) {
+        return super.afterSetTag(context, tag, value)
+      }
+
+    }
+    decorator.setMatchingTag("foo")
+    decorator.setMatchingValue("bar")
+    decorator.setSetTag("newFoo")
+    decorator.setSetValue("newBar")
+    tracer.addDecorator(decorator)
+
+    def span = SpanFactory.newSpanTracer(tracer)
+    new StringTag("foo").set(span, "bar")
+
+    expect:
+    span.getTags().containsKey("newFoo")
+    ((String) span.getTags().get("newFoo")) == "newBar"
+
+  }
+}