[example] create restspark package to build it with gradlew

dd-trace-examples/rest-spark/rest-spark.gradle

@@ -1,3 +1,7 @@
+plugins {
+  id "com.github.johnrengelman.shadow" version "2.0.1"
+}
+
 apply from: "${rootDir}/gradle/java.gradle"
 apply from: "${rootDir}/gradle/jacoco.gradle"
 
@@ -8,16 +12,29 @@ sourceCompatibility = 1.8
 targetCompatibility = 1.8
 
 dependencies {
-
-//  compile fileTree(dir: 'libs', include: ['*.jar'])
   compile project(':dd-trace')
+
   compile 'com.sparkjava:spark-core:2.6.0'
   compile 'org.mongodb:mongodb-driver:3.4.2'
+
   compile 'io.opentracing:opentracing-api:0.30.0'
   compile 'io.opentracing:opentracing-util:0.30.0'
-  compile 'io.opentracing.contrib:opentracing-mongo-driver:0.0.2'
+  compile 'io.opentracing.contrib:opentracing-mongo-driver:0.0.3'
+
   compile group: 'ch.qos.logback', name: 'logback-classic', version: '1.2.3'
   compile group: 'org.slf4j', name: 'slf4j-api', version: '1.7.25'
-
-
+}
+
+jar {
+  manifest {
+    attributes 'Main-Class': 'com.datadoghq.example.restspark.SparkApplication'
+  }
+}
+
+shadowJar {
+  mergeServiceFiles()
+}
+
+task wrapper(type: Wrapper) {
+  gradleVersion = '4.0'
 }

dd-trace-examples/rest-spark/src/main/java/com/datadoghq/example/restspark/MongoDriver.java

@@ -1,3 +1,5 @@
+package com.datadoghq.example.restspark;
+
 import com.mongodb.MongoClient;
 import com.mongodb.MongoClientURI;
 import com.mongodb.client.MongoDatabase;

dd-trace-examples/rest-spark/src/main/java/com/datadoghq/example/restspark/SparkApplication.java

@@ -1,3 +1,5 @@
+package com.datadoghq.example.restspark;
+
 import static spark.Spark.get;
 
 import com.mongodb.client.MongoCollection;
@@ -7,7 +9,7 @@ import io.opentracing.Tracer;
 import java.util.Arrays;
 import org.bson.Document;
 
-public class Hello {
+public class SparkApplication {
   private static MongoDatabase mDatabase;
   private static Tracer mTracer;
 

dd-trace-examples/rest-spark/src/main/resources/dd-trace.yaml

@@ -1,34 +1,9 @@
-# Main service name for the app
 defaultServiceName: rest-spark
 
-# The writer to use.
-# Could be: LoggingWritter or DDAgentWriter (default)
 writer:
-  # LoggingWriter: Spans are logged using the application configuration
-  # DDAgentWriter: Spans are forwarding to a Datadog trace Agent
-  #  - Param 'host': the hostname where the DD trace Agent is running (default: localhost)
-  #  - Param 'port': the port to reach the DD trace Agent (default: 8126)
   type: DDAgentWriter
   host: localhost
   port: 8126
 
-# The sampler to use.
-# Could be: AllSampler (default) or RateSampler
 sampler:
-  # AllSampler: all spans are reported to the writer
-  # RateSample: only a portion of spans are reported to the writer
-  #  - Param 'rate': the portion of spans to keep
   type: AllSampler
-  # Skip some traces if the root span tag values matches some regexp patterns
-  # skipTagsPatterns: {"http.url": ".*/demo/add.*"}
-
-# Enable custom tracing (Custom annotations for now)
-# enableCustomAnnotationTracingOver: ["io","org","com"]
-
-# Disable some instrumentations
-# disabledInstrumentations: ["opentracing-apache-httpclient", "opentracing-mongo-driver", "opentracing-web-servlet-filter"]
-
-decorators:
-  - type: DBComponent
-    matchingValue: java-mongo
-    setValue: mongo-spark