Draft: Selective api poc

gapic-generator-java/src/main/java/com/google/api/generator/gapic/protoparser/Parser.java

@@ -14,6 +14,7 @@
 
 package com.google.api.generator.gapic.protoparser;
 
+import com.google.api.ClientLibrarySettings;
 import com.google.api.ClientProto;
 import com.google.api.DocumentationRule;
 import com.google.api.FieldBehavior;
@@ -70,6 +71,7 @@
 import com.google.protobuf.Descriptors.FileDescriptor;
 import com.google.protobuf.Descriptors.MethodDescriptor;
 import com.google.protobuf.Descriptors.ServiceDescriptor;
+import com.google.protobuf.ProtocolStringList;
 import com.google.protobuf.compiler.PluginProtos.CodeGeneratorRequest;
 import java.util.ArrayList;
 import java.util.Arrays;
@@ -425,6 +427,66 @@ public static List<Service> parseService(
         Transport.GRPC);
   }
 
+  private static String getPakkageName(FileDescriptor fileDescriptor, ServiceDescriptor s,
+      Optional<GapicServiceConfig> serviceConfigOpt) {
+    String pakkage = TypeParser.getPackage(fileDescriptor);
+    // Override Java package with that specified in gapic.yaml.
+    // this override is deprecated and legacy support only
+    // see go/client-user-guide#configure-long-running-operation-polling-timeouts-optional
+    if (serviceConfigOpt.isPresent()
+        && serviceConfigOpt.get().getLanguageSettingsOpt().isPresent()) {
+      GapicLanguageSettings languageSettings =
+          serviceConfigOpt.get().getLanguageSettingsOpt().get();
+      pakkage = languageSettings.pakkage();
+    }
+    return pakkage;
+  }
+
+  private static String getOverriddenServiceName(FileDescriptor fileDescriptor, ServiceDescriptor s,
+      Optional<GapicServiceConfig> serviceConfigOpt) {
+    String serviceName = s.getName();
+    String overriddenServiceName = serviceName;
+    String pakkage = TypeParser.getPackage(fileDescriptor);
+    // Override Java package with that specified in gapic.yaml.
+    // this override is deprecated and legacy support only
+    // see go/client-user-guide#configure-long-running-operation-polling-timeouts-optional
+    if (serviceConfigOpt.isPresent()
+        && serviceConfigOpt.get().getLanguageSettingsOpt().isPresent()) {
+      GapicLanguageSettings languageSettings =
+          serviceConfigOpt.get().getLanguageSettingsOpt().get();
+      overriddenServiceName =
+          languageSettings.getJavaServiceName(fileDescriptor.getPackage(), s.getName());
+    }
+    return overriddenServiceName;
+  }
+  private static boolean shouldIncludeMethod(
+      MethodDescriptor method, Optional<com.google.api.Service> serviceYamlProtoOpt) {
+    method.getInputType().getFullName();
+    // default to include all when no service yaml or no library setting section.
+    if (!serviceYamlProtoOpt.isPresent()
+        || serviceYamlProtoOpt.get().getPublishing().getLibrarySettingsCount() == 0) {
+      return true;
+    }
+    List<ClientLibrarySettings> librarySettingsList =
+        serviceYamlProtoOpt.get().getPublishing().getLibrarySettingsList();
+    // TODO: verify if get(0) is reliable. may need to use package version.
+    // should be okay since it's cut per version. no harm in verifying.
+    // library settings version (required): http://google3/google/api/client.proto;l=29-32;rcl=651426419
+    ProtocolStringList includeMethodsList =
+        librarySettingsList
+            .get(0)
+            .getJavaSettings()
+            .getCommon()
+            .getSelectiveGapicGeneration()
+            .getMethodsList();
+    // default to include all when nothing specified.
+    if (includeMethodsList.isEmpty()) {
+      return true;
+    }
+    // may need to preprocess method name with override package name
+    return includeMethodsList.contains(method.getFullName());
+  }
+
   public static List<Service> parseService(
       FileDescriptor fileDescriptor,
       Map<String, Message> messageTypes,
@@ -438,13 +500,20 @@ public static List<Service> parseService(
         .filter(
             serviceDescriptor -> {
               List<MethodDescriptor> methodsList = serviceDescriptor.getMethods();
-              if (methodsList.isEmpty()) {
+              List<MethodDescriptor> methodListSelected =
+                  methodsList.stream()
+                      .filter(
+                          method -> {
+                            return shouldIncludeMethod(method, serviceYamlProtoOpt);
+                          })
+                      .collect(Collectors.toList());
+              if (methodListSelected.isEmpty()) {
                 LOGGER.warning(
                     String.format(
                         "Service %s has no RPC methods and will not be generated",
                         serviceDescriptor.getName()));
               }
-              return !methodsList.isEmpty();
+              return !methodListSelected.isEmpty();
             })
         .map(
             s -> {
@@ -498,6 +567,8 @@ public static List<Service> parseService(
               String pakkage = TypeParser.getPackage(fileDescriptor);
               String originalJavaPackage = pakkage;
               // Override Java package with that specified in gapic.yaml.
+              // this override is deprecated and legacy support only
+              // see go/client-user-guide#configure-long-running-operation-polling-timeouts-optional
               if (serviceConfigOpt.isPresent()
                   && serviceConfigOpt.get().getLanguageSettingsOpt().isPresent()) {
                 GapicLanguageSettings languageSettings =
@@ -723,6 +794,9 @@ static List<Method> parseMethods(
         parseAutoPopulatedMethodsAndFields(serviceYamlProtoOpt);
 
     for (MethodDescriptor protoMethod : serviceDescriptor.getMethods()) {
+      if (!shouldIncludeMethod(protoMethod, serviceYamlProtoOpt)) {
+        continue;
+      }
       // Parse the method.
       TypeNode inputType = TypeParser.parseType(protoMethod.getInputType());
       Method.Builder methodBuilder = Method.builder();

gapic-generator-java/src/test/java/com/google/api/generator/gapic/composer/ComposerTest.java

@@ -20,6 +20,8 @@
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 import com.google.api.generator.engine.ast.ClassDefinition;
+import com.google.api.generator.engine.ast.IdentifierNode;
+import com.google.api.generator.engine.ast.MethodDefinition;
 import com.google.api.generator.engine.ast.ScopeNode;
 import com.google.api.generator.engine.writer.JavaWriterVisitor;
 import com.google.api.generator.gapic.composer.comment.CommentComposer;
@@ -172,6 +174,49 @@ void testComposePackageInfo_emptyGapicContext_returnsNull() {
     assertNull(Composer.composePackageInfo(GapicContext.EMPTY));
   }
 
+  @Test
+  void testComposeSelectively_shouldComposeOnlyOneHelperResource() {
+    GapicContext context = GrpcTestProtoLoader.instance().parseSelectiveGenerationTesting();
+    List<GapicClass> resourceNameHelperClasses = Composer.generateResourceNameHelperClasses(context);
+    assertEquals(1, resourceNameHelperClasses.size());
+    for (GapicClass clazz: resourceNameHelperClasses) {
+      String className = clazz.classDefinition().classIdentifier().name();
+      Assert.assertGoldenClass(this.getClass(), clazz,
+          "SelectiveGenerated" + className + ".golden");
+    }
+  }
+
+  @Test
+  void testComposeSelectively_serviceClientShouldOnlyContainSelectedMethods() {
+    GapicContext context = GrpcTestProtoLoader.instance().parseSelectiveGenerationTesting();
+    List<GapicClass> serviceClasses = Composer.composeServiceClasses(context);
+    assertEquals(10, serviceClasses.size());
+    for (GapicClass clazz: serviceClasses) {
+      if (clazz
+          .classDefinition()
+          .classIdentifier()
+          .name()
+          .equals("EchoServiceShouldGeneratePartialClient")) {
+        assertEquals(25, clazz.classDefinition().methods().size());
+        for (MethodDefinition method : clazz.classDefinition().methods()) {
+          String methodName = method.methodIdentifier().name();
+          if (method.isConstructor()) {
+            continue;
+          }
+          assertTrue(
+              methodName.startsWith("echo")
+                  || methodName.startsWith("chat")
+                  || methodName.startsWith("create")
+                  || methodName.startsWith("get")
+                  || methodName.startsWith("close")
+                  || methodName.startsWith("shutdown")
+                  || methodName.startsWith("is")
+                  || methodName.startsWith("awaitTermination"));
+        }
+      }
+    }
+  }
+
   private List<GapicClass> getTestClassListFromService(Service testService) {
     GapicClass testClass =
         GrpcServiceCallableFactoryClassComposer.instance()