Ability to add extra service information (WIP)

dd-trace/src/main/java/com/datadoghq/trace/DDTracer.java

@@ -7,13 +7,19 @@ import com.datadoghq.trace.sampling.AllSampler;
 import com.datadoghq.trace.sampling.Sampler;
 import com.datadoghq.trace.writer.LoggingWriter;
 import com.datadoghq.trace.writer.Writer;
+import com.fasterxml.jackson.annotation.JsonIgnore;
 import io.opentracing.ActiveSpan;
 import io.opentracing.ActiveSpanSource;
 import io.opentracing.BaseSpan;
 import io.opentracing.SpanContext;
 import io.opentracing.propagation.Format;
 import io.opentracing.util.ThreadLocalActiveSpanSource;
-import java.util.*;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Queue;
 import java.util.concurrent.ThreadLocalRandom;
 import lombok.extern.slf4j.Slf4j;
 
@@ -37,6 +43,7 @@ public class DDTracer extends ThreadLocalActiveSpanSource implements io.opentrac
   private final Map<String, List<AbstractDecorator>> spanContextDecorators = new HashMap<>();
 
   private final CodecRegistry registry;
+  private final List<Service> services = new ArrayList<>();
 
   /** Default constructor, trace/spans are logged, no trace/span dropped */
   public DDTracer() {
@@ -137,6 +144,33 @@ public class DDTracer extends ThreadLocalActiveSpanSource implements io.opentrac
     return "DDTracer{" + "writer=" + writer + ", sampler=" + sampler + '}';
   }
 
+  /**
+   * Register additional information about a service. Service additional information are a Datadog
+   * feature only. Services are reported through a specific Datadog endpoint.
+   *
+   * @param service additional service information
+   */
+  public void addServiceInfo(final Service service) {
+    services.add(service);
+    // Update the write
+    try {
+      // We don't bother to send multiple times the list of services at this time
+      writer.writeServices(services);
+    } catch (final Throwable ex) {
+      log.warn("Failed to report additional service information, reason: {}", ex.getMessage());
+    }
+  }
+
+  /**
+   * Return the list of additional service information registered
+   *
+   * @return the list of additional service information
+   */
+  @JsonIgnore
+  public List<Service> getServiceInfo() {
+    return services;
+  }
+
   private static class CodecRegistry {
 
     private final Map<Format<?>, Codec<?>> codecs = new HashMap<>();

dd-trace/src/main/java/com/datadoghq/trace/Service.java

@@ -0,0 +1,47 @@
+package com.datadoghq.trace;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class Service {
+
+  private final String name;
+  private final String appName;
+  private final Service.AppType appType;
+
+  public Service(final String name, final String appName, final AppType appType) {
+    this.name = name;
+    this.appName = appName;
+    this.appType = appType;
+  }
+
+  @JsonProperty("service")
+  public String getName() {
+    return name;
+  }
+
+  @JsonProperty("app")
+  public String getAppName() {
+    return appName;
+  }
+
+  @JsonProperty("app_type")
+  public AppType getAppType() {
+    return appType;
+  }
+
+  public enum AppType {
+    WEB("web"),
+    DB("db"),
+    CUSTOM("custom");
+
+    private final String type;
+
+    AppType(final String type) {
+      this.type = type;
+    }
+
+    public String toString() {
+      return type;
+    }
+  }
+}

dd-trace/src/main/java/com/datadoghq/trace/writer/DDAgentWriter.java

@@ -1,6 +1,7 @@
 package com.datadoghq.trace.writer;
 
 import com.datadoghq.trace.DDBaseSpan;
+import com.datadoghq.trace.Service;
 import com.google.auto.service.AutoService;
 import java.util.List;
 import java.util.concurrent.Callable;
@@ -80,6 +81,9 @@ public class DDAgentWriter implements Writer {
     queueFullReported = false;
   }
 
+  @Override
+  public void writeServices(final List<Service> services) {}
+
   /* (non-Javadoc)
    * @see com.datadoghq.trace.writer.Writer#start()
    */

dd-trace/src/main/java/com/datadoghq/trace/writer/ListWriter.java

@@ -1,8 +1,10 @@
 package com.datadoghq.trace.writer;
 
 import com.datadoghq.trace.DDBaseSpan;
+import com.datadoghq.trace.Service;
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
+import sun.reflect.generics.reflectiveObjects.NotImplementedException;
 
 /** List writer used by tests mostly */
 public class ListWriter extends CopyOnWriteArrayList<List<DDBaseSpan<?>>> implements Writer {
@@ -20,6 +22,11 @@ public class ListWriter extends CopyOnWriteArrayList<List<DDBaseSpan<?>>> implem
     add(trace);
   }
 
+  @Override
+  public void writeServices(final List<Service> services) {
+    throw new NotImplementedException();
+  }
+
   @Override
   public void start() {
     clear();

dd-trace/src/main/java/com/datadoghq/trace/writer/LoggingWriter.java

@@ -1,6 +1,7 @@
 package com.datadoghq.trace.writer;
 
 import com.datadoghq.trace.DDBaseSpan;
+import com.datadoghq.trace.Service;
 import com.google.auto.service.AutoService;
 import java.util.List;
 import lombok.extern.slf4j.Slf4j;
@@ -14,6 +15,11 @@ public class LoggingWriter implements Writer {
     log.info("write(trace): {}", trace);
   }
 
+  @Override
+  public void writeServices(final List<Service> services) {
+    log.info("additional service information: {}", services);
+  }
+
   @Override
   public void close() {
     log.info("close()");

dd-trace/src/main/java/com/datadoghq/trace/writer/Writer.java

@@ -1,6 +1,7 @@
 package com.datadoghq.trace.writer;
 
 import com.datadoghq.trace.DDBaseSpan;
+import com.datadoghq.trace.Service;
 import java.util.List;
 
 /** A writer is responsible to send collected spans to some place */
@@ -13,6 +14,13 @@ public interface Writer {
    */
   void write(List<DDBaseSpan<?>> trace);
 
+  /**
+   * Report additional service information to the endpoint
+   *
+   * @param services a list of extra information about services
+   */
+  void writeServices(List<Service> services);
+
   /** Start the writer */
   void start();
 

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

@@ -0,0 +1,63 @@
+package com.datadoghq.trace
+
+import com.datadoghq.trace.sampling.AllSampler
+import com.datadoghq.trace.writer.DDAgentWriter
+import org.mockito.Mockito
+import spock.lang.Specification
+
+class ServiceTest extends Specification {
+
+
+  def "getter/setter"() {
+
+    setup:
+    def service = new Service("service-name", "app-name", Service.AppType.CUSTOM)
+
+    expect:
+    service.getName() == "service-name"
+    service.getAppName() == "app-name"
+    service.getAppType() == Service.AppType.CUSTOM
+
+  }
+
+  def "enum"() {
+
+    expect:
+    Service.AppType.values().size() == 3
+    Service.AppType.DB.toString() == "db"
+    Service.AppType.WEB.toString() == "web"
+    Service.AppType.CUSTOM.toString() == "custom"
+
+  }
+
+  def "add extra info about a specific service"() {
+
+    setup:
+    def tracer = new DDTracer()
+    def service = new Service("service-name", "app-name", Service.AppType.CUSTOM)
+
+    when:
+    tracer.addServiceInfo(service)
+
+    then:
+    tracer.getServiceInfo().size() == 1
+    tracer.getServiceInfo().get(0) == service
+
+  }
+
+  def "add a extra info is reported to the writer"() {
+
+    setup:
+    def writer = Mockito.spy(new DDAgentWriter())
+    def tracer = new DDTracer(writer, new AllSampler())
+
+
+    when:
+    tracer.addServiceInfo(new Service("service-name", "app-name", Service.AppType.CUSTOM))
+
+    then:
+    Mockito.verify(writer, Mockito.times(1)).writeServices(Mockito.any(List.class))
+
+  }
+
+}