[example] update dropwizard example

dd-trace-examples/dropwizard-mongo-client/README.md

@@ -12,15 +12,20 @@ We also demonstrate user cross-process tracing through the `TracedClient` exampl
 
 #### Prerequisites
 
-1. Make sure that you have a local mongo database running (hostname: `localhost`, port: `27017`).
-2. No process holding the 8080 and the 8081 port, they are used by the Dropwizard server.
-
-If you're using Docker, you can run a mongo instance as follow:
-
+Be sure to build the project so that the latest version of ``dd-trace-java`` components are used. You can build
+all libraries and examples launching from the ``dd-trace-java`` root folder:
 ```bash
-docker run -it --rm -p 27017:27017 --name mongo -d mongo
+./gradlew clean shadowJar
 ```
 
+Then you can start all services via Docker:
+```bash
+cd dd-trace-examples/dropwizard-mongo-client
+DD_API_KEY=<your_datadog_api_key> docker-compose up -d
+```
+
+A valid ``DD_API_KEY`` is required to post collected traces to the Datadog backend.
+
 #### Run the application
 
 If you want to enable tracing you have to launch the application with the Datadog java agent.
@@ -33,7 +38,6 @@ First, get the latest version of the dd-java-agent:
 wget -O dd-java-agent.jar 'https://search.maven.org/remote_content?g=com.datadoghq&a=dd-java-agent&v=LATEST'
 ```
 
-
 Then, build the app add the agent to the JVM. That can be done as follow:
 ```
 cd path/to/dd-trace-examples/dropwizard-mongo-client
@@ -42,14 +46,15 @@ java -javaagent:/path/to/dd-java-agent.jar -jar build/libs/dropwizard-mongo-clie
 ```
 ### Generate traces
 
-
 #### With your web browser
 
 Once the application runs. Go to the following url:
 
-* [http://localhost:8080/demo/add?title=some-book-title&isbn=1234&page=42]()
-* [http://localhost:8080/demo/]()
+* [http://localhost:8080/demo/add?title=some-book-title&isbn=1234&page=42][1]
+* [http://localhost:8080/demo/][2]
 
+[1]: http://localhost:8080/demo/add?title=some-book-title&isbn=1234&page=42
+[2]: http://localhost:8080/demo/
 
 Then get back to Datadog and wait a bit to see a trace coming.
 

dd-trace-examples/dropwizard-mongo-client/docker-compose.yml

@@ -0,0 +1,12 @@
+mongo:
+    image: mongo:3.2
+    ports:
+        - "127.0.0.1:27017:27017"
+
+ddagent:
+    image: datadog/docker-dd-agent
+    environment:
+        - DD_BIND_HOST=0.0.0.0
+        - DD_API_KEY
+    ports:
+        - "127.0.0.1:8126:8126"

dd-trace-examples/dropwizard-mongo-client/dropwizard-mongo-client.gradle

@@ -11,8 +11,8 @@ description = 'dropwizard-mongo-client'
 dependencies {
   compile project(':dd-trace-annotations')
 
-  compile group: 'io.opentracing', name: 'opentracing-api', version: '0.+'
-  compile group: 'io.opentracing', name: 'opentracing-util', version: '0.+'
+  compile group: 'io.opentracing', name: 'opentracing-api', version: '0.30.0'
+  compile group: 'io.opentracing', name: 'opentracing-util', version: '0.30.0'
 
   compile group: 'io.dropwizard', name: 'dropwizard-core', version: '0.9.2'
   compile group: 'org.mongodb', name: 'mongo-java-driver', version: '3.4.2'

dd-trace-examples/dropwizard-mongo-client/src/main/java/com/example/helloworld/resources/SimpleCrudResource.java

@@ -6,7 +6,7 @@ import com.google.common.base.Optional;
 import com.mongodb.MongoClient;
 import com.mongodb.client.MongoCursor;
 import com.mongodb.client.MongoDatabase;
-import io.opentracing.tag.StringTag;
+import io.opentracing.ActiveSpan;
 import io.opentracing.util.GlobalTracer;
 import java.util.ArrayList;
 import java.util.List;
@@ -91,33 +91,38 @@ public class SimpleCrudResource {
     }
 
     // The methodDB is traced (see below), this will be produced a new child span
-    beforeDB();
+    afterDB();
 
     return books;
   }
 
   /**
-   * The beforeDB is traced using the annotation @trace with a custom operationName and a custom
+   * The beforeDB is traced using the annotation @Trace with a custom operationName and a custom
    * tag.
    *
    * @throws InterruptedException
    */
-  @Trace(operationName = "Before DB")
+  @Trace(operationName = "database.before")
   public void beforeDB() throws InterruptedException {
-    new StringTag("mytag").set(GlobalTracer.get().activeSpan(), "myvalue");
-    Thread.sleep(333);
+    ActiveSpan currentSpan = GlobalTracer.get().activeSpan();
+    if (currentSpan != null) {
+      currentSpan.setTag("status", "started");
+      Thread.sleep(10);
+    }
   }
 
   /**
-   * The beforeDB is traced using the annotation @trace with a custom operationName and a custom
-   * tag.
+   * The afterDB is traced using the annotation @Trace with a custom operationName and a custom tag.
    *
    * @throws InterruptedException
    */
-  @Trace(operationName = "After DB")
+  @Trace(operationName = "database.after")
   public void afterDB() throws InterruptedException {
-    new StringTag("mytag").set(GlobalTracer.get().activeSpan(), "myvalue");
-    Thread.sleep(111);
+    ActiveSpan currentSpan = GlobalTracer.get().activeSpan();
+    if (currentSpan != null) {
+      currentSpan.setTag("status", "started");
+      Thread.sleep(10);
+    }
   }
 
   /** Flush resources */

dd-trace-examples/dropwizard-mongo-client/src/main/resources/dd-trace.yaml

@@ -1,8 +1,8 @@
 # Service name used if none is provided in the app
-defaultServiceName: java-app
+defaultServiceName: dropwizard-example
 
 # The writer to use.
-# Could be: LoggingWritter or DDAgentWriter (default)
+# Could be: LoggingWriter or DDAgentWriter (default)
 writer:
   # LoggingWriter: Spans are logged using the application configuration
   # DDAgentWriter: Spans are forwarding to a Datadog Agent