Merge branch 'dev' into gpolaert/dev

# Conflicts:
#	src/main/java/com/datadoghq/trace/impl/DDTracer.java

src/main/java/com/datadoghq/trace/impl/DDSpan.java

@@ -196,7 +196,7 @@ public class DDSpan implements io.opentracing.Span {
      * @see io.opentracing.Span#log(java.lang.String, java.lang.Object)
      */
     public Span log(String s) {
-        logger.debug("`log` method is not implemented. Doing nothing");
+        logger.debug("`log` method is not implemented. Provided log: {}",s);
         return this;
     }
 
@@ -204,7 +204,7 @@ public class DDSpan implements io.opentracing.Span {
      * @see io.opentracing.Span#log(java.lang.String, java.lang.Object)
      */
     public Span log(long l, String s) {
-        logger.debug("`log` method is not implemented. Doing nothing");
+        logger.debug("`log` method is not implemented. Provided log: {}",s);
         return this;
     }
 
@@ -212,7 +212,7 @@ public class DDSpan implements io.opentracing.Span {
      * @see io.opentracing.Span#log(java.lang.String, java.lang.Object)
      */
     public Span log(String s, Object o) {
-        logger.debug("`log` method is not implemented. Doing nothing");
+        logger.debug("`log` method is not implemented. Provided log: {}",s);
         return this;
     }
 
@@ -220,7 +220,7 @@ public class DDSpan implements io.opentracing.Span {
      * @see io.opentracing.Span#log(long, java.lang.String, java.lang.Object)
      */
     public Span log(long l, String s, Object o) {
-        logger.debug("`log` method is not implemented. Doing nothing");
+        logger.debug("`log` method is not implemented. Provided log: {}",s);
         return this;
     }
 
@@ -314,8 +314,8 @@ public class DDSpan implements io.opentracing.Span {
         return this;
     }
 
-    public Span setType(String type) {
-        this.context().setType(type);
+    public Span setSpanType(String type) {
+        this.context().setSpanType(type);
         return this;
     }
 }

src/main/java/com/datadoghq/trace/impl/DDSpanContext.java

@@ -1,7 +1,11 @@
 package com.datadoghq.trace.impl;
 
 
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 
@@ -76,7 +80,7 @@ public class DDSpanContext implements io.opentracing.SpanContext {
         this.parentId = parentId;
 
         if (baggageItems == null) {
-            this.baggageItems = Collections.emptyMap();
+            this.baggageItems = new HashMap<String, String>();
         } else {
             this.baggageItems = baggageItems;
         }
@@ -128,9 +132,6 @@ public class DDSpanContext implements io.opentracing.SpanContext {
     }
 
     public void setBaggageItem(String key, String value) {
-        if (this.baggageItems.isEmpty()) {
-            this.baggageItems = new HashMap<String, String>();
-        }
         this.baggageItems.put(key, value);
     }
 
@@ -166,14 +167,23 @@ public class DDSpanContext implements io.opentracing.SpanContext {
      * @param value the value of the value
      * @return the builder instance
      */
-    public void setTag(String tag, Object value) {
+    public synchronized void setTag(String tag, Object value) {
         if (this.tags.isEmpty()) {
             this.tags = new HashMap<String, Object>();
         }
         this.tags.put(tag, value);
+        
+        //Call decorators
+        for(DDSpanContextDecorator decorator:tracer.getSpanContextDecorators()){
+        	decorator.afterSetTag(this, tag, value);
+        }
     }
 
-    @Override
+    public synchronized Map<String, Object> getTags() {
+	    return Collections.unmodifiableMap(tags);
+	}
+
+	@Override
     public String toString() {
         return "Span [traceId=" + traceId
                 + ", spanId=" + spanId
@@ -188,10 +198,6 @@ public class DDSpanContext implements io.opentracing.SpanContext {
         return operationName;
     }
 
-    public Map<String, Object> getTags() {
-        return tags;
-    }
-
     public void setServiceName(String serviceName) {
         this.serviceName = serviceName;
     }
@@ -200,7 +206,7 @@ public class DDSpanContext implements io.opentracing.SpanContext {
         this.resourceName = resourceName;
     }
 
-    public void setType(String type) {
-        this.spanType = type;
+    public void setSpanType(String spanType) {
+        this.spanType = spanType;
     }
 }

src/main/java/com/datadoghq/trace/impl/DDSpanContextDecorator.java

@@ -0,0 +1,17 @@
+package com.datadoghq.trace.impl;
+
+/**
+ * Span decorators are called when new tags are written and proceed to various remappings and enrichments
+ */
+public interface DDSpanContextDecorator {
+
+	/**
+	 * A tag was just added to the context. The decorator provides a way to enrich the context a bit more.
+	 * 
+	 * @param context the target context to decorate
+	 * @param tag The tag set
+	 * @param value the value assigned to the tag
+	 */
+	public void afterSetTag(DDSpanContext context , String tag, Object value);
+	
+}

src/main/java/com/datadoghq/trace/impl/DDTracer.java

@@ -1,18 +1,24 @@
 package com.datadoghq.trace.impl;
 
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
 import com.datadoghq.trace.Codec;
 import com.datadoghq.trace.Sampler;
 import com.datadoghq.trace.Writer;
 import com.datadoghq.trace.propagation.impl.HTTPCodec;
 import com.datadoghq.trace.writer.impl.LoggingWritter;
+
 import io.opentracing.Span;
 import io.opentracing.SpanContext;
 import io.opentracing.propagation.Format;
-import io.opentracing.propagation.TextMap;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
-import java.util.*;
 
 /**
  * DDTracer makes it easy to send traces and span to DD using the OpenTracing instrumentation.
@@ -28,6 +34,11 @@ public class DDTracer implements io.opentracing.Tracer {
      */
     private final Sampler sampler;
 
+    /**
+     * Span context decorators
+     */
+    private final List<DDSpanContextDecorator> spanContextDecorators = new ArrayList<DDSpanContextDecorator>();
+
 
     private final static Logger logger = LoggerFactory.getLogger(DDTracer.class);
     private final CodecRegistry registry;
@@ -46,7 +57,25 @@ public class DDTracer implements io.opentracing.Tracer {
         registry.register(Format.Builtin.HTTP_HEADERS, new HTTPCodec());
     }
 
-    public DDSpanBuilder buildSpan(String operationName) {
+    /**
+     * Returns the list of span context decorators
+     *
+     * @return the list of span context decorators
+     */
+    public List<DDSpanContextDecorator> getSpanContextDecorators() {
+		return Collections.unmodifiableList(spanContextDecorators);
+	}
+
+    /**
+     * Add a new decorator in the list ({@link DDSpanContextDecorator})
+     *
+     * @param decorator The decorator in the list
+     */
+    public void addDecorator(DDSpanContextDecorator decorator){
+    	spanContextDecorators.add(decorator);
+    }
+
+	public DDSpanBuilder buildSpan(String operationName) {
         return new DDSpanBuilder(operationName);
     }
 
@@ -236,7 +265,7 @@ public class DDTracer implements io.opentracing.Tracer {
                     serviceName,
                     this.operationName,
                     this.resourceName,
-                    this.parent == null ? Collections.<String, String>emptyMap() : p.getBaggageItems(),
+                    this.parent == null ? new HashMap<String, String>() : p.getBaggageItems(),
                     errorFlag,
                     spanType,
                     this.tags,

src/main/java/com/datadoghq/trace/impl/MapperDecorator.java

@@ -0,0 +1,38 @@
+package com.datadoghq.trace.impl;
+
+import java.util.Map;
+
+/**
+ * Remap some tags to other tags
+ */
+public class MapperDecorator implements DDSpanContextDecorator {
+
+	public static final String SPAN_TYPE = "spanType";
+	public static final String SERVICE_NAME = "serviceName";
+	public static final String RESOURCE_NAME = "resourceName";
+	
+	private final Map<String,String> mappings;
+	
+	public MapperDecorator(Map<String, String> mappings) {
+		super();
+		this.mappings = mappings;
+	}
+
+	@Override
+	public void afterSetTag(DDSpanContext context, String tag, Object value) {
+		String toAssign = mappings.get(tag);
+		if(toAssign != null){
+			if(toAssign.equals(SPAN_TYPE)){
+				context.setSpanType(String.valueOf(value));
+			}else if(toAssign.equals(SERVICE_NAME)){
+				context.setServiceName(String.valueOf(value));
+			}else if(toAssign.equals(RESOURCE_NAME)){
+				context.setResourceName(String.valueOf(value));
+			}else{
+				//General remap
+				context.setTag(toAssign, value);
+			}
+		}
+	}
+	
+}

src/test/java/com/datadoghq/trace/impl/DDSpanTest.java

@@ -1,10 +1,10 @@
 package com.datadoghq.trace.impl;
 
-import org.junit.Test;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import java.util.Collections;
 
-import static org.assertj.core.api.Assertions.assertThat;
+import org.junit.Test;
 
 
 public class DDSpanTest {
@@ -44,7 +44,7 @@ public class DDSpanTest {
         assertThat(span.getResourceName()).isEqualTo(expected);
 
         expected = "type";
-        span.setType(expected);
+        span.setSpanType(expected);
         assertThat(span.getType()).isEqualTo(expected);
 
     }