Adding Span Grpc Health Check Service (#91)

Author: keshavpeswani

agent-providers/span/src/main/java/com/expedia/www/haystack/agent/span/service/SpanGrpcHealthService.java

@@ -0,0 +1,15 @@
+package com.expedia.www.haystack.agent.span.service;
+
+import io.grpc.health.v1.HealthCheckRequest;
+import io.grpc.health.v1.HealthCheckResponse;
+import io.grpc.health.v1.HealthGrpc;
+import io.grpc.stub.StreamObserver;
+
+public class SpanGrpcHealthService extends HealthGrpc.HealthImplBase {
+
+    @Override
+    public void check(HealthCheckRequest request, StreamObserver<HealthCheckResponse> responseObserver) {
+        responseObserver.onNext(HealthCheckResponse.newBuilder().setStatus(HealthCheckResponse.ServingStatus.SERVING).build());
+        responseObserver.onCompleted();
+    }
+}

agent-providers/span/src/main/java/com/expedia/www/haystack/agent/span/spi/SpanAgent.java

@@ -20,6 +20,7 @@
 import com.expedia.www.haystack.agent.core.BaseAgent;
 import com.expedia.www.haystack.agent.span.enricher.Enricher;
 import com.expedia.www.haystack.agent.span.service.SpanAgentGrpcService;
+import com.expedia.www.haystack.agent.span.service.SpanGrpcHealthService;
 import com.typesafe.config.Config;
 import io.grpc.Server;
 import io.grpc.netty.NettyServerBuilder;
@@ -55,6 +56,7 @@ public void initialize(final Config config) throws IOException {
                 .permitKeepAliveWithoutCalls(true)
                 .permitKeepAliveTime(KEEP_ALIVE_TIME_IN_SECONDS, TimeUnit.SECONDS)
                 .addService(new SpanAgentGrpcService(dispatchers, enrichers))
+                .addService(new SpanGrpcHealthService())
                 .build()
                 .start();
 

api/pom.xml

@@ -22,6 +22,10 @@
             <groupId>io.grpc</groupId>
             <artifactId>grpc-all</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.grpc</groupId>
+            <artifactId>grpc-services</artifactId>
+        </dependency>
     </dependencies>
 
     <build>

pom.xml

@@ -124,6 +124,12 @@
                 <version>${grpc.version}</version>
             </dependency>
 
+            <dependency>
+                <groupId>io.grpc</groupId>
+                <artifactId>grpc-services</artifactId>
+                <version>${grpc.version}</version>
+            </dependency>
+
             <dependency>
                 <groupId>com.google.protobuf</groupId>
                 <artifactId>protobuf-java-util</artifactId>