feat: Parse Host Service Name

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

@@ -155,6 +155,8 @@ public abstract class AbstractServiceStubSettingsClassComposer implements ClassC
   protected static final VariableExpr DEFAULT_SERVICE_SCOPES_VAR_EXPR =
       createDefaultServiceScopesVarExpr();
 
+  private static final VariableExpr HOST_SERVICE_NAME_VAR_EXPR = createHostServiceNameVarExpr();
+
   protected AbstractServiceStubSettingsClassComposer(TransportContext transportContext) {
     this.transportContext = transportContext;
   }
@@ -492,6 +494,23 @@ private static List<Statement> createClassStatements(
     Function<Expr, Statement> exprToStatementFn = e -> ExprStatement.withExpr(e);
     List<Statement> statements = new ArrayList<>();
 
+    VariableExpr hostServiceNameVarExpr =
+        HOST_SERVICE_NAME_VAR_EXPR
+            .toBuilder()
+            .setIsDecl(true)
+            .setScope(ScopeNode.PRIVATE)
+            .setIsStatic(true)
+            .setIsFinal(true)
+            .build();
+
+    statements.add(
+        exprToStatementFn.apply(
+            AssignmentExpr.builder()
+                .setVariableExpr(hostServiceNameVarExpr)
+                .setValueExpr(
+                    ValueExpr.withValue(StringObjectValue.withValue(service.hostServiceName())))
+                .build()));
+
     // Assign DEFAULT_SERVICE_SCOPES.
     statements.add(SettingsCommentComposer.DEFAULT_SCOPES_COMMENT);
     VariableExpr defaultServiceScopesDeclVarExpr =
@@ -1899,6 +1918,12 @@ protected MethodDefinition createNestedClassCreateDefaultMethod(
                 ValueExpr.withValue(
                     PrimitiveValue.builder().setType(TypeNode.BOOLEAN).setValue("true").build()))
             .build());
+    bodyExprs.add(
+        MethodInvocationExpr.builder()
+            .setExprReferenceExpr(builderVarExpr)
+            .setMethodName("setHostServiceName")
+            .setArguments(HOST_SERVICE_NAME_VAR_EXPR)
+            .build());
     bodyStatements.addAll(
         bodyExprs.stream().map(e -> ExprStatement.withExpr(e)).collect(Collectors.toList()));
     bodyStatements.add(EMPTY_LINE_STATEMENT);
@@ -2190,6 +2215,11 @@ private static VariableExpr createNestedRetryParamDefinitionsVarExpr() {
             .build());
   }
 
+  private static VariableExpr createHostServiceNameVarExpr() {
+    return VariableExpr.withVariable(
+        Variable.builder().setName("HOST_SERVICE_NAME").setType(TypeNode.STRING).build());
+  }
+
   private static String getPagedResponseTypeName(String methodName) {
     return String.format(PAGED_RESPONSE_TYPE_NAME_PATTERN, JavaStyle.toUpperCamelCase(methodName));
   }

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() {
+    // Default Host 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/DeprecatedServiceStubSettings.golden

@@ -69,6 +69,7 @@ import org.threeten.bp.Duration;
 @Deprecated
 @Generated("by gapic-generator-java")
 public class DeprecatedServiceStubSettings extends StubSettings<DeprecatedServiceStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().add("https://www.googleapis.com/auth/cloud-platform").build();
@@ -238,6 +239,7 @@ public class DeprecatedServiceStubSettings extends StubSettings<DeprecatedServic
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

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

@@ -91,6 +91,7 @@ import org.threeten.bp.Duration;
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoStubSettings extends StubSettings<EchoStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().add("https://www.googleapis.com/auth/cloud-platform").build();
@@ -487,6 +488,7 @@ public class EchoStubSettings extends StubSettings<EchoStubSettings> {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

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

@@ -98,6 +98,7 @@ import org.threeten.bp.Duration;
  */
 @Generated("by gapic-generator-java")
 public class LoggingServiceV2StubSettings extends StubSettings<LoggingServiceV2StubSettings> {
+  private static final String HOST_SERVICE_NAME = "logging";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder()
@@ -623,6 +624,7 @@ public class LoggingServiceV2StubSettings extends StubSettings<LoggingServiceV2S
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

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

@@ -98,6 +98,7 @@ import org.threeten.bp.Duration;
  */
 @Generated("by gapic-generator-java")
 public class PublisherStubSettings extends StubSettings<PublisherStubSettings> {
+  private static final String HOST_SERVICE_NAME = "pubsub";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder()
@@ -664,6 +665,7 @@ public class PublisherStubSettings extends StubSettings<PublisherStubSettings> {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/EchoStubSettings.golden

@@ -96,6 +96,7 @@ import org.threeten.bp.Duration;
 @BetaApi
 @Generated("by gapic-generator-java")
 public class EchoStubSettings extends StubSettings<EchoStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().add("https://www.googleapis.com/auth/cloud-platform").build();
@@ -515,6 +516,7 @@ public class EchoStubSettings extends StubSettings<EchoStubSettings> {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }
@@ -528,6 +530,7 @@ public class EchoStubSettings extends StubSettings<EchoStubSettings> {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/grpcrest/goldens/WickedStubSettings.golden

@@ -65,6 +65,7 @@ import javax.annotation.Generated;
 @BetaApi
 @Generated("by gapic-generator-java")
 public class WickedStubSettings extends StubSettings<WickedStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().build();
@@ -234,6 +235,7 @@ public class WickedStubSettings extends StubSettings<WickedStubSettings> {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/rest/goldens/ComplianceStubSettings.golden

@@ -66,6 +66,7 @@ import javax.annotation.Generated;
 @BetaApi
 @Generated("by gapic-generator-java")
 public class ComplianceStubSettings extends StubSettings<ComplianceStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().build();
@@ -305,6 +306,7 @@ public class ComplianceStubSettings extends StubSettings<ComplianceStubSettings>
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }

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 getHostServiceName();
+
   @Nullable
   public abstract String getEndpoint();
 
@@ -202,6 +206,7 @@ public static ClientContext create(StubSettings settings) throws IOException {
     }
     EndpointContext endpointContext =
         EndpointContext.newBuilder()
+            .setHostServiceName(settings.getHostServiceName())
             .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)
+        .setHostServiceName(settings.getHostServiceName())
         .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 setHostServiceName(String hostServiceName);
+
     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 +40,15 @@
 @InternalApi
 @AutoValue
 public abstract class EndpointContext {
+  /**
+   * HostServiceName is HostName for Google Cloud Services. It follows the format of
+   * `{HostServiceName}.googleapis.com`. For example, speech.googleapis.com would have a
+   * HostServiceName of speech and cloudasset.googleapis.com would have a HostServiceName of
+   * cloudasset.
+   */
+  @Nullable
+  public abstract String hostServiceName();
+
   /**
    * ClientSettingsEndpoint is the endpoint value set via the ClientSettings/StubSettings classes.
    */
@@ -117,6 +126,14 @@ public String getResolvedEndpoint() {
 
   @AutoValue.Builder
   public abstract static class Builder {
+    /**
+     * HostServiceName is HostName for Google Cloud Services. It follows the format of
+     * `{HostServiceName}.googleapis.com`. For example, speech.googleapis.com would have a
+     * HostServiceName of speech and cloudasset.googleapis.com would have a HostServiceName of
+     * cloudasset.
+     */
+    public abstract Builder setHostServiceName(String hostServiceName);
+
     /**
      * 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 hostServiceName;
   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.hostServiceName = builder.hostServiceName;
     this.endpoint = builder.endpoint;
     this.mtlsEndpoint = builder.mtlsEndpoint;
     this.switchToMtlsEndpointAllowed = builder.switchToMtlsEndpointAllowed;
@@ -137,6 +140,11 @@ public final ApiClock getClock() {
     return clock;
   }
 
+  // Package-Private scope for internal use only. Shared between StubSettings and ClientContext
+  final String getHostServiceName() {
+    return hostServiceName;
+  }
+
   public final String getEndpoint() {
     return endpoint;
   }
@@ -211,6 +219,7 @@ public abstract static class Builder<
     private HeaderProvider internalHeaderProvider;
     private TransportChannelProvider transportChannelProvider;
     private ApiClock clock;
+    private String hostServiceName;
     private String endpoint;
     private String mtlsEndpoint;
     private String quotaProjectId;
@@ -236,6 +245,7 @@ protected Builder(StubSettings settings) {
       this.headerProvider = settings.headerProvider;
       this.internalHeaderProvider = settings.internalHeaderProvider;
       this.clock = settings.clock;
+      this.hostServiceName = settings.hostServiceName;
       this.endpoint = settings.endpoint;
       this.mtlsEndpoint = settings.mtlsEndpoint;
       this.switchToMtlsEndpointAllowed = settings.switchToMtlsEndpointAllowed;
@@ -272,6 +282,7 @@ protected Builder(ClientContext clientContext) {
         this.headerProvider = new NoHeaderProvider();
         this.internalHeaderProvider = new NoHeaderProvider();
         this.clock = NanoClock.getDefaultClock();
+        this.hostServiceName = null;
         this.endpoint = null;
         this.mtlsEndpoint = null;
         this.quotaProjectId = null;
@@ -292,6 +303,7 @@ protected Builder(ClientContext clientContext) {
         this.internalHeaderProvider =
             FixedHeaderProvider.create(clientContext.getInternalHeaders());
         this.clock = clientContext.getClock();
+        this.hostServiceName = clientContext.getHostServiceName();
         this.endpoint = clientContext.getEndpoint();
         if (this.endpoint != null) {
           this.mtlsEndpoint = this.endpoint.replace("googleapis.com", "mtls.googleapis.com");
@@ -414,6 +426,14 @@ public B setClock(ApiClock clock) {
       return self();
     }
 
+    // This meant to be used internally by GAPIC clients to configure an endpoint.
+    // Users should avoid settings this as it could change their endpoint.
+    @InternalApi
+    public B setHostServiceName(String hostServiceName) {
+      this.hostServiceName = hostServiceName;
+      return self();
+    }
+
     public B setEndpoint(String endpoint) {
       this.endpoint = endpoint;
       this.switchToMtlsEndpointAllowed = false;

showcase/gapic-showcase/src/main/java/com/google/showcase/v1beta1/stub/ComplianceStubSettings.java

@@ -103,6 +103,7 @@
 @BetaApi
 @Generated("by gapic-generator-java")
 public class ComplianceStubSettings extends StubSettings<ComplianceStubSettings> {
+  private static final String HOST_SERVICE_NAME = "";
   /** The default scopes of the service. */
   private static final ImmutableList<String> DEFAULT_SERVICE_SCOPES =
       ImmutableList.<String>builder().build();
@@ -519,6 +520,7 @@ private static Builder createDefault() {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }
@@ -532,6 +534,7 @@ private static Builder createHttpJsonDefault() {
       builder.setEndpoint(getDefaultEndpoint());
       builder.setMtlsEndpoint(getDefaultMtlsEndpoint());
       builder.setSwitchToMtlsEndpointAllowed(true);
+      builder.setHostServiceName(HOST_SERVICE_NAME);
 
       return initDefaults(builder);
     }