feat: Parse Host Service Name (#2300)

* refactor: Add transportchannelprovider's endpoint to EndpointContext

* chore: Add Endpoint tests for ClientContext

* chore: Resolve PR comments

* feat: Add HostServiceName to StubSettings

* chore: Add comments for hostservicename

* chore: Fix setEndpoint logic

* chore: Add InternalApi annotation to setDefaultHost in StubSettings

* fix: Expose HostServiceName in ClientContext

* chore: Add comments for hostservicename

* chore: Set hostServiceName to package private scope

* chore: Update integration tests

* chore: Resolve PR comments

* chore: Do not generate getServiceName if hostServiceName is empty

* chore: Add tests for parsing Host Service Name

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/comment/SettingsCommentComposer.java

@@ -57,6 +57,9 @@ public class SettingsCommentComposer {
 
   public static final CommentStatement DEFAULT_EXECUTOR_PROVIDER_BUILDER_METHOD_COMMENT =
       toSimpleComment("Returns a builder for the default ExecutorProvider for this service.");
+
+  public static final CommentStatement DEFAULT_SERVICE_NAME_METHOD_COMMENT =
+      toSimpleComment("Returns the default service name.");
   public static final CommentStatement DEFAULT_SERVICE_ENDPOINT_METHOD_COMMENT =
       toSimpleComment("Returns the default service endpoint.");
   public static final CommentStatement DEFAULT_SERVICE_MTLS_ENDPOINT_METHOD_COMMENT =

gapic-generator-java/src/main/java/com/google/api/generator/gapic/composer/common/AbstractServiceStubSettingsClassComposer.java

@@ -97,6 +97,7 @@
 import com.google.api.generator.gapic.model.Service;
 import com.google.api.generator.gapic.utils.JavaStyle;
 import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
@@ -1137,9 +1138,27 @@ private MethodDefinition createCreateStubMethod(Service service, TypeStore typeS
   private List<MethodDefinition> createDefaultHelperAndGetterMethods(
       Service service, TypeStore typeStore) {
     List<MethodDefinition> javaMethods = new ArrayList<>();
+    TypeNode returnType;
+
+    // Create the getServiceName method.
+    if (!Strings.isNullOrEmpty(service.hostServiceName())) {
+      returnType = TypeNode.STRING;
+      javaMethods.add(
+          MethodDefinition.builder()
+              .setHeaderCommentStatements(
+                  SettingsCommentComposer.DEFAULT_SERVICE_NAME_METHOD_COMMENT)
+              .setIsOverride(true)
+              .setScope(ScopeNode.PUBLIC)
+              .setIsStatic(false)
+              .setReturnType(returnType)
+              .setName("getServiceName")
+              .setReturnExpr(
+                  ValueExpr.withValue(StringObjectValue.withValue(service.hostServiceName())))
+              .build());
+    }
 
     // Create the defaultExecutorProviderBuilder method.
-    TypeNode returnType =
+    returnType =
         TypeNode.withReference(
             ConcreteReference.withClazz(InstantiatingExecutorProvider.Builder.class));
     javaMethods.add(

gapic-generator-java/src/main/java/com/google/api/generator/gapic/model/Service.java

@@ -52,6 +52,12 @@ public boolean hasDescription() {
     return !Strings.isNullOrEmpty(description());
   }
 
+  public String hostServiceName() {
+    // Host Service Name is guaranteed to exist and be non-null and non-empty
+    // Parser will fail if the default host is not supplied
+    return parseHostServiceName(defaultHost());
+  }
+
   public String apiShortName() {
     if (!Strings.isNullOrEmpty(defaultHost())) {
       return parseApiShortName(defaultHost());
@@ -184,6 +190,17 @@ private static String parseApiVersion(String protoPackage) {
     return apiVersion;
   }
 
+  // Parse the service name from the default host configured in the protos
+  // or service yaml file. For Google Cloud Services, the default host value
+  // is expected to contain `.googleapis.com`. Exceptions may exist (i.e. localhost),
+  // in which case we will return an empty string.
+  private static String parseHostServiceName(String defaultHost) {
+    if (defaultHost.contains(".googleapis.com")) {
+      return Iterables.getFirst(Splitter.on(".").split(defaultHost), defaultHost);
+    }
+    return "";
+  }
+
   // Parse defaultHost for apiShortName for the RegionTag. Need to account for regional default
   // endpoints like
   // "us-east1-pubsub.googleapis.com".

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/LoggingServiceV2StubSettings.golden

@@ -422,6 +422,12 @@ public class LoggingServiceV2StubSettings extends StubSettings<LoggingServiceV2S
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "logging";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpc/goldens/PublisherStubSettings.golden

@@ -431,6 +431,12 @@ public class PublisherStubSettings extends StubSettings<PublisherStubSettings> {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "pubsub";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

gapic-generator-java/src/test/java/com/google/api/generator/gapic/model/ServiceTest.java

@@ -177,4 +177,17 @@ public void hasAnyEnabledMethodsForTransport_shouldThrowExceptionForGRPCRESTTran
     Service testService = testServiceBuilder.build();
     testService.hasAnyEnabledMethodsForTransport(Transport.GRPC_REST);
   }
+
+  @Test
+  public void hostServiceName_googleApisDefaultHost() {
+    Service service = testServiceBuilder.setDefaultHost("test.googleapis.com").build();
+    assertThat(service.hostServiceName()).isEqualTo("test");
+  }
+
+  @Test
+  public void hostServiceName_nonGoogleApisDefaultHost() {
+    // Default Host is localhost:7469
+    Service service = testServiceBuilder.build();
+    assertThat(service.hostServiceName()).isEqualTo("");
+  }
 }

gax-java/gax/src/main/java/com/google/api/gax/rpc/ClientContext.java

@@ -100,6 +100,10 @@ public abstract class ClientContext {
   @Nonnull
   public abstract Duration getStreamWatchdogCheckInterval();
 
+  // Package-Private scope for internal use only. Shared between StubSettings and ClientContext
+  @Nullable
+  abstract String getServiceName();
+
   @Nullable
   public abstract String getEndpoint();
 
@@ -202,6 +206,7 @@ public static ClientContext create(StubSettings settings) throws IOException {
     }
     EndpointContext endpointContext =
         EndpointContext.newBuilder()
+            .setServiceName(settings.getServiceName())
             .setClientSettingsEndpoint(settings.getEndpoint())
             .setTransportChannelProviderEndpoint(
                 settings.getTransportChannelProvider().getEndpoint())
@@ -258,6 +263,7 @@ public static ClientContext create(StubSettings settings) throws IOException {
         .setInternalHeaders(ImmutableMap.copyOf(settings.getInternalHeaderProvider().getHeaders()))
         .setClock(clock)
         .setDefaultCallContext(defaultCallContext)
+        .setServiceName(settings.getServiceName())
         .setEndpoint(settings.getEndpoint())
         .setQuotaProjectId(settings.getQuotaProjectId())
         .setStreamWatchdog(watchdog)
@@ -323,6 +329,9 @@ public abstract static class Builder {
 
     public abstract Builder setDefaultCallContext(ApiCallContext defaultCallContext);
 
+    // Package-Private scope for internal use only. Shared between StubSettings and ClientContext
+    abstract Builder setServiceName(String serviceName);
+
     public abstract Builder setEndpoint(String endpoint);
 
     public abstract Builder setQuotaProjectId(String QuotaProjectId);

gax-java/gax/src/main/java/com/google/api/gax/rpc/EndpointContext.java

@@ -40,6 +40,14 @@
 @InternalApi
 @AutoValue
 public abstract class EndpointContext {
+  /**
+   * ServiceName is host URI for Google Cloud Services. It follows the format of
+   * `{ServiceName}.googleapis.com`. For example, speech.googleapis.com would have a ServiceName of
+   * speech and cloudasset.googleapis.com would have a ServiceName of cloudasset.
+   */
+  @Nullable
+  public abstract String serviceName();
+
   /**
    * ClientSettingsEndpoint is the endpoint value set via the ClientSettings/StubSettings classes.
    */
@@ -117,6 +125,13 @@ public String getResolvedEndpoint() {
 
   @AutoValue.Builder
   public abstract static class Builder {
+    /**
+     * ServiceName is host URI for Google Cloud Services. It follows the format of
+     * `{ServiceName}.googleapis.com`. For example, speech.googleapis.com would have a ServiceName
+     * of speech and cloudasset.googleapis.com would have a ServiceName of cloudasset.
+     */
+    public abstract Builder setServiceName(String serviceName);
+
     /**
      * ClientSettingsEndpoint is the endpoint value set via the ClientSettings/StubSettings classes.
      */

gax-java/gax/src/main/java/com/google/api/gax/rpc/StubSettings.java

@@ -32,6 +32,7 @@
 import com.google.api.core.ApiClock;
 import com.google.api.core.ApiFunction;
 import com.google.api.core.BetaApi;
+import com.google.api.core.InternalApi;
 import com.google.api.core.NanoClock;
 import com.google.api.gax.core.CredentialsProvider;
 import com.google.api.gax.core.ExecutorProvider;
@@ -70,6 +71,7 @@ public abstract class StubSettings<SettingsT extends StubSettings<SettingsT>> {
   private final HeaderProvider internalHeaderProvider;
   private final TransportChannelProvider transportChannelProvider;
   private final ApiClock clock;
+  private final String serviceName;
   private final String endpoint;
   private final String mtlsEndpoint;
   private final String quotaProjectId;
@@ -96,6 +98,7 @@ protected StubSettings(Builder builder) {
     this.headerProvider = builder.headerProvider;
     this.internalHeaderProvider = builder.internalHeaderProvider;
     this.clock = builder.clock;
+    this.serviceName = builder.serviceName;
     this.endpoint = builder.endpoint;
     this.mtlsEndpoint = builder.mtlsEndpoint;
     this.switchToMtlsEndpointAllowed = builder.switchToMtlsEndpointAllowed;
@@ -137,6 +140,13 @@ public final ApiClock getClock() {
     return clock;
   }
 
+  // Intended for Internal Use and Overriden by generated ServiceStubSettings classes.
+  // Meant to be shared between StubSettings and ClientContext.
+  @InternalApi
+  public String getServiceName() {
+    return "";
+  }
+
   public final String getEndpoint() {
     return endpoint;
   }
@@ -211,6 +221,7 @@ public abstract static class Builder<
     private HeaderProvider internalHeaderProvider;
     private TransportChannelProvider transportChannelProvider;
     private ApiClock clock;
+    private String serviceName;
     private String endpoint;
     private String mtlsEndpoint;
     private String quotaProjectId;
@@ -236,6 +247,7 @@ protected Builder(StubSettings settings) {
       this.headerProvider = settings.headerProvider;
       this.internalHeaderProvider = settings.internalHeaderProvider;
       this.clock = settings.clock;
+      this.serviceName = settings.serviceName;
       this.endpoint = settings.endpoint;
       this.mtlsEndpoint = settings.mtlsEndpoint;
       this.switchToMtlsEndpointAllowed = settings.switchToMtlsEndpointAllowed;
@@ -272,6 +284,7 @@ protected Builder(ClientContext clientContext) {
         this.headerProvider = new NoHeaderProvider();
         this.internalHeaderProvider = new NoHeaderProvider();
         this.clock = NanoClock.getDefaultClock();
+        this.serviceName = null;
         this.endpoint = null;
         this.mtlsEndpoint = null;
         this.quotaProjectId = null;
@@ -292,6 +305,7 @@ protected Builder(ClientContext clientContext) {
         this.internalHeaderProvider =
             FixedHeaderProvider.create(clientContext.getInternalHeaders());
         this.clock = clientContext.getClock();
+        this.serviceName = clientContext.getServiceName();
         this.endpoint = clientContext.getEndpoint();
         if (this.endpoint != null) {
           this.mtlsEndpoint = this.endpoint.replace("googleapis.com", "mtls.googleapis.com");

test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/ConnectionServiceStubSettings.java

@@ -182,6 +182,12 @@ public ConnectionServiceStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "apigeeconnect";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/apigeeconnect/src/com/google/cloud/apigeeconnect/v1/stub/TetherStubSettings.java

@@ -102,6 +102,12 @@ public TetherStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "apigeeconnect";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/asset/src/com/google/cloud/asset/v1/stub/AssetServiceStubSettings.java

@@ -571,6 +571,12 @@ public AssetServiceStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "cloudasset";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/bigtable/src/com/google/cloud/bigtable/data/v2/stub/BigtableStubSettings.java

@@ -166,6 +166,12 @@ public BigtableStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "bigtable";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/AddressesStubSettings.java

@@ -289,6 +289,12 @@ public AddressesStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "compute";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/compute/src/com/google/cloud/compute/v1small/stub/RegionOperationsStubSettings.java

@@ -114,6 +114,12 @@ public RegionOperationsStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "compute";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/credentials/src/com/google/cloud/iam/credentials/v1/stub/IamCredentialsStubSettings.java

@@ -140,6 +140,12 @@ public IamCredentialsStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "iamcredentials";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/iam/src/com/google/iam/v1/stub/IAMPolicyStubSettings.java

@@ -119,6 +119,12 @@ public IAMPolicyStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "iam-meta-api";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/kms/src/com/google/cloud/kms/v1/stub/KeyManagementServiceStubSettings.java

@@ -639,6 +639,12 @@ public KeyManagementServiceStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "cloudkms";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();

test/integration/goldens/library/src/com/google/cloud/example/library/v1/stub/LibraryServiceStubSettings.java

@@ -306,6 +306,12 @@ public LibraryServiceStub createStub() throws IOException {
             "Transport not supported: %s", getTransportChannelProvider().getTransportName()));
   }
 
+  /** Returns the default service name. */
+  @Override
+  public String getServiceName() {
+    return "library-example";
+  }
+
   /** Returns a builder for the default ExecutorProvider for this service. */
   public static InstantiatingExecutorProvider.Builder defaultExecutorProviderBuilder() {
     return InstantiatingExecutorProvider.newBuilder();