Support setting library header in grpc services (#1078)

- add libraryName() and libraryVersion() to ServiceOptions
- use setClientLibHeader in DefaultPubSubRpc

Author: mziccard

gcloud-java-core/src/main/java/com/google/cloud/ServiceOptions.java

@@ -68,9 +68,11 @@ public abstract class ServiceOptions<ServiceT extends Service<OptionsT>, Service
   private static final String MANIFEST_ARTIFACT_ID_KEY = "artifactId";
   private static final String MANIFEST_VERSION_KEY = "Implementation-Version";
   private static final String ARTIFACT_ID = "gcloud-java-core";
-  private static final String APPLICATION_BASE_NAME = "gcloud-java";
-  private static final String APPLICATION_NAME = getApplicationName();
-  private static final long serialVersionUID = -6410263550484023006L;
+  private static final String LIBRARY_NAME = "gcloud-java";
+  private static final String LIBRARY_VERSION = getLibraryVersion();
+  private static final String APPLICATION_NAME =
+      LIBRARY_VERSION == null ? LIBRARY_NAME : LIBRARY_NAME + "/" + LIBRARY_VERSION;
+  private static final long serialVersionUID = 3049375916337507361L;
 
   private final String projectId;
   private final String host;
@@ -439,6 +441,20 @@ public String applicationName() {
     return APPLICATION_NAME;
   }
 
+  /**
+   * Returns the library's name, {@code gcloud-java}, as a string.
+   */
+  public String libraryName() {
+    return LIBRARY_NAME;
+  }
+
+  /**
+   * Returns the library's version as a string.
+   */
+  public String libraryVersion() {
+    return LIBRARY_VERSION;
+  }
+
   protected int baseHashCode() {
     return Objects.hash(projectId, host, authCredentialsState, retryParams, serviceFactoryClassName,
         serviceRpcFactoryClassName, clock);
@@ -491,7 +507,7 @@ static <T> T getFromServiceLoader(Class<? extends T> clazz, T defaultInstance) {
     return Iterables.getFirst(ServiceLoader.load(clazz), defaultInstance);
   }
 
-  private static String getApplicationName() {
+  private static String getLibraryVersion() {
     String version = null;
     try {
       Enumeration<URL> resources =
@@ -507,6 +523,6 @@ private static String getApplicationName() {
     } catch (IOException e) {
       // ignore
     }
-    return version != null ? APPLICATION_BASE_NAME + "/" + version : APPLICATION_BASE_NAME;
+    return version;
   }
 }

gcloud-java-core/src/test/java/com/google/cloud/ServiceOptionsTest.java

@@ -30,6 +30,7 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.Set;
+import java.util.regex.Pattern;
 
 public class ServiceOptionsTest {
   private static final String JSON_KEY =
@@ -80,6 +81,9 @@ public class ServiceOptionsTest {
   private static final TestServiceOptions DEFAULT_OPTIONS =
       TestServiceOptions.builder().projectId("project-id").build();
   private static final TestServiceOptions OPTIONS_COPY = OPTIONS.toBuilder().build();
+  private static final String LIBRARY_NAME = "gcloud-java";
+  private static final Pattern APPLICATION_NAME_PATTERN =
+      Pattern.compile(LIBRARY_NAME + "(/[0-9]+.[0-9]+.[0-9]+)?");
 
   private static class TestClock extends Clock {
     @Override
@@ -214,6 +218,16 @@ public void testBaseEquals() {
     assertNotEquals(DEFAULT_OPTIONS, OPTIONS);
   }
 
+  @Test
+  public void testLibraryName() {
+    assertEquals(LIBRARY_NAME, OPTIONS.libraryName());
+  }
+
+  @Test
+  public void testApplicationName() {
+    assertTrue(APPLICATION_NAME_PATTERN.matcher(OPTIONS.applicationName()).matches());
+  }
+
   @Test
   public void testBaseHashCode() {
     assertEquals(OPTIONS.hashCode(), OPTIONS_COPY.hashCode());

gcloud-java-pubsub/src/main/java/com/google/cloud/pubsub/spi/DefaultPubSubRpc.java

@@ -16,6 +16,8 @@
 
 package com.google.cloud.pubsub.spi;
 
+import static com.google.common.base.MoreObjects.firstNonNull;
+
 import com.google.api.gax.core.RetrySettings;
 import com.google.api.gax.grpc.ApiCallSettings;
 import com.google.api.gax.grpc.ApiException;
@@ -118,11 +120,15 @@ public void onFailure(Throwable error) {
   public DefaultPubSubRpc(PubSubOptions options) throws IOException {
     executorFactory = new InternalPubSubOptions(options).executorFactory();
     executor = executorFactory.get();
+    String libraryName = options.libraryName();
+    String libraryVersion = firstNonNull(options.libraryVersion(), "");
     try {
-      PublisherSettings.Builder pubBuilder =
-          PublisherSettings.defaultBuilder().provideExecutorWith(executor, false);
-      SubscriberSettings.Builder subBuilder =
-          SubscriberSettings.defaultBuilder().provideExecutorWith(executor, false);
+      PublisherSettings.Builder pubBuilder = PublisherSettings.defaultBuilder()
+          .provideExecutorWith(executor, false)
+          .setClientLibHeader(libraryName, libraryVersion);
+      SubscriberSettings.Builder subBuilder = SubscriberSettings.defaultBuilder()
+          .provideExecutorWith(executor, false)
+          .setClientLibHeader(libraryName, libraryVersion);
       // todo(mziccard): PublisherSettings should support null/absent credentials for testing
       if (options.host().contains("localhost")
           || options.authCredentials().equals(AuthCredentials.noAuth())) {