feat: REST GAPIC (REGAPIC) Support for Java (#3275)

rules_gapic/gapic.bzl

@@ -40,11 +40,13 @@ def _gapic_srcjar_impl(ctx):
         _set_args(attr.service_yaml, "--service_yaml=", arguments, inputs)
         _set_args(attr.package_yaml2, "--package_yaml2=", arguments, inputs)
         _set_args(attr.grpc_service_config, "--grpc_service_config=", arguments, inputs)
+        _set_args(attr.transport, "--transport=", arguments)
     else:
         _set_args(attr.language, "--language=", arguments)
         _set_args(attr.src, "--descriptor=", arguments, inputs)
         _set_args(attr.package, "--package=", arguments)
         _set_args(attr.grpc_service_config, "--grpc_service_config=", arguments, inputs)
+        _set_args(attr.transport, "--transport=", arguments)
 
     gapic_generator = ctx.executable.gapic_generator
     ctx.actions.run(
@@ -72,6 +74,7 @@ gapic_srcjar = rule(
         "package": attr.string(mandatory = False),
         "output_suffix": attr.string(mandatory = False, default = ".srcjar"),
         "grpc_service_config": attr.label(mandatory = False, allow_single_file = True),
+        "transport": attr.string(mandatory = False),
         "gapic_generator": attr.label(
             default = Label("//:gapic_generator"),
             executable = True,

rules_gapic/java/java_gapic.bzl

@@ -78,6 +78,7 @@ def java_gapic_srcjar(
         package = None,
         service_yaml = None,
         grpc_service_config = None,
+        transport = None,
         **kwargs):
     raw_srcjar_name = "%s_raw" % name
 
@@ -90,6 +91,7 @@ def java_gapic_srcjar(
         language = "java",
         package = package,
         grpc_service_config = grpc_service_config,
+        transport = transport,
         **kwargs
     )
 
@@ -132,6 +134,7 @@ def java_gapic_library(
         package = None,
         gen_resource_name = True,
         grpc_service_config = None,
+        transport = None,
         deps = [],
         test_deps = [],
         **kwargs):
@@ -144,6 +147,7 @@ def java_gapic_library(
         artifact_type = "GAPIC_CODE",
         package = package,
         grpc_service_config = grpc_service_config,
+        transport = transport,
         **kwargs
     )
 
@@ -162,10 +166,7 @@ def java_gapic_library(
         "@com_google_protobuf//:protobuf_java",
         "@com_google_api_api_common//jar",
         "@com_google_api_gax_java//gax:gax",
-        "@com_google_api_gax_java//gax-grpc:gax_grpc",
         "@com_google_guava_guava//jar",
-        "@io_grpc_grpc_java//core:core",
-        "@io_grpc_grpc_java//protobuf:protobuf",
         "@com_google_code_findbugs_jsr305//jar",
         "@org_threeten_threetenbp//jar",
         "@io_opencensus_opencensus_api//jar",
@@ -175,6 +176,17 @@ def java_gapic_library(
         "@javax_annotation_javax_annotation_api//jar",
     ]
 
+    if transport == "rest":
+        actual_deps += [
+            "@com_google_api_gax_java//gax-httpjson:gax_httpjson",
+        ]
+    else:
+        actual_deps += [
+            "@com_google_api_gax_java//gax-grpc:gax_grpc",
+            "@io_grpc_grpc_java//core:core",
+            "@io_grpc_grpc_java//protobuf:protobuf",
+        ]
+
     native.java_library(
         name = name,
         srcs = [":%s.srcjar" % srcjar_name],
@@ -183,16 +195,24 @@ def java_gapic_library(
     )
 
     actual_test_deps = test_deps + [
-        "@com_google_api_gax_java//gax-grpc:gax_grpc_testlib",
         "@com_google_api_gax_java//gax:gax_testlib",
         "@com_google_code_gson_gson//jar",
-        "@io_grpc_grpc_java//auth:auth",
-        "@io_grpc_grpc_netty_shaded//jar",
-        "@io_grpc_grpc_java//stub:stub",
-        "@io_opencensus_opencensus_contrib_grpc_metrics//jar",
         "@junit_junit//jar",
     ]
 
+    if transport == "rest":
+        actual_test_deps += [
+            "@com_google_api_gax_java//gax-httpjson:gax_httpjson_testlib",
+        ]
+    else:
+        actual_test_deps += [
+            "@com_google_api_gax_java//gax-grpc:gax_grpc_testlib",
+            "@io_grpc_grpc_java//auth:auth",
+            "@io_grpc_grpc_netty_shaded//jar",
+            "@io_grpc_grpc_java//stub:stub",
+            "@io_opencensus_opencensus_contrib_grpc_metrics//jar",
+        ]
+
     native.java_library(
         name = "%s_test" % name,
         srcs = [":%s-test.srcjar" % srcjar_name],

rules_gapic/java/java_gapic_pkg.bzl

@@ -160,6 +160,7 @@ def java_gapic_assembly_gradle_pkg(
         name,
         deps,
         assembly_name = None,
+        transport = None,
         **kwargs):
     package_dir = name
     if assembly_name:
@@ -206,9 +207,14 @@ def java_gapic_assembly_gradle_pkg(
         grpc_target_dep = ["%s" % grpc_target]
 
     if client_deps:
+        if transport == "rest":
+            template_label = Label("//rules_gapic/java:resources/gradle/client_disco.gradle.tmpl")
+        else:
+            template_label = Label("//rules_gapic/java:resources/gradle/client.gradle.tmpl")
+
         _java_gapic_gradle_pkg(
             name = client_target,
-            template_label = Label("//rules_gapic/java:resources/gradle/client.gradle.tmpl"),
+            template_label = template_label,
             deps = proto_target_dep + client_deps,
             test_deps = grpc_target_dep + client_test_deps,
             **kwargs

src/main/java/com/google/api/codegen/GeneratorMain.java

@@ -149,6 +149,17 @@ public class GeneratorMain {
           .argName("GRPC-SERVICE-CONFIG")
           .required(false)
           .build();
+  private static final Option TRANSPORT =
+      Option.builder()
+          .longOpt("transport")
+          .desc(
+              "List of transports to support. Valid transport names ('grpc' or 'rest') are"
+                  + " separated by '+'. Default is 'grpc'. NOTE: for now, GAPICs support only"
+                  + " the first transport in the list.")
+          .hasArg()
+          .argName("TRANSPORT")
+          .required(false)
+          .build();
 
   public static void printAvailableCommands() {
     System.err.println("  Available artifact types:");
@@ -249,6 +260,7 @@ public static void gapicGeneratorMain(ArtifactType artifactType, String[] args)
     options.addOption(OUTPUT_OPTION);
     options.addOption(SAMPLE_YAML_NONREQUIRED_OPTION);
     options.addOption(GRPC_SERVICE_CONFIG_OPTION);
+    options.addOption(TRANSPORT);
     Option enabledArtifactsOption =
         Option.builder()
             .longOpt("enabled_artifacts")
@@ -299,6 +311,9 @@ public static void gapicGeneratorMain(ArtifactType artifactType, String[] args)
 
     checkFile(toolOptions.get(ToolOptions.DESCRIPTOR_SET));
 
+    if (cl.getOptionValue(TRANSPORT.getLongOpt()) != null) {
+      toolOptions.set(GapicGeneratorApp.TRANSPORT, cl.getOptionValue(TRANSPORT.getLongOpt()));
+    }
     if (cl.getOptionValues(SERVICE_YAML_NONREQUIRED_OPTION.getLongOpt()) != null) {
       toolOptions.set(
           ToolOptions.CONFIG_FILES,
@@ -346,6 +361,7 @@ public static ToolOptions createCodeGeneratorOptionsFromProtoc(String[] args)
     options.addOption(DESCRIPTOR_SET_OPTION);
     options.addOption(LANGUAGE_OPTION);
     options.addOption(TARGET_API_PROTO_PACKAGE);
+    options.addOption(TRANSPORT);
 
     CommandLine cl = (new DefaultParser()).parse(options, args);
 

src/main/java/com/google/api/codegen/config/GapicInterfaceContext.java

@@ -246,8 +246,7 @@ public List<MethodModel> getPublicMethods() {
 
   @Override
   public boolean isSupported(MethodModel method) {
-    boolean supported = true;
-    supported &=
+    boolean supported =
         getFeatureConfig().enableGrpcStreaming() || !MethodConfig.isGrpcStreamingMethod(method);
     supported &= getMethodConfig(method).getVisibility() != VisibilityConfig.DISABLED;
     return supported;

src/main/java/com/google/api/codegen/config/GapicProductConfig.java

@@ -135,7 +135,7 @@ public GapicProductConfig withPackageName(String packageName) {
   @Nullable
   public static GapicProductConfig create(
       Model model, ConfigProto configProto, TargetLanguage language) {
-    return create(model, configProto, null, null, null, language, null);
+    return create(model, configProto, null, null, null, language, null, TransportProtocol.GRPC);
   }
 
   /**
@@ -150,6 +150,8 @@ public static GapicProductConfig create(
    *     generate clients for.
    * @param clientPackage The desired package name for the generated client.
    * @param language The language that this config will be used to generate a client in.
+   * @param grpcServiceConfig Method retries configuration.
+   * @param transportProtocol Transport protocol to support.
    */
   @Nullable
   public static GapicProductConfig create(
@@ -159,7 +161,8 @@ public static GapicProductConfig create(
       @Nullable String protoPackage,
       @Nullable String clientPackage,
       TargetLanguage language,
-      @Nullable ServiceConfig grpcServiceConfig) {
+      @Nullable ServiceConfig grpcServiceConfig,
+      TransportProtocol transportProtocol) {
 
     final String defaultPackage;
     SymbolTable symbolTable = model.getSymbolTable();
@@ -305,8 +308,6 @@ public static GapicProductConfig create(
       return null;
     }
 
-    TransportProtocol transportProtocol = TransportProtocol.GRPC;
-
     String clientPackageName;
     LanguageSettingsProto settings =
         configProto.getLanguageSettingsMap().get(language.toString().toLowerCase());

src/main/java/com/google/api/codegen/gapic/GapicGeneratorApp.java

@@ -24,6 +24,7 @@
 import com.google.api.codegen.config.GapicProductConfig;
 import com.google.api.codegen.config.PackageMetadataConfig;
 import com.google.api.codegen.config.PackagingConfig;
+import com.google.api.codegen.config.TransportProtocol;
 import com.google.api.codegen.grpc.ServiceConfig;
 import com.google.api.codegen.samplegen.v1p2.SampleConfigProto;
 import com.google.api.codegen.util.MultiYamlReader;
@@ -112,6 +113,14 @@ public class GapicGeneratorApp extends ToolDriverBase {
           "The filepath of the JSON gRPC Service Config file.",
           "");
 
+  public static final Option<String> TRANSPORT =
+      ToolOptions.createOption(
+          String.class,
+          "transport",
+          "List of transports to use ('rest' or 'grpc') separated by '+'. NOTE: For now"
+              + " we only support the first transport in the list.",
+          "grpc");
+
   private ArtifactType artifactType;
 
   private final GapicWriter gapicWriter;
@@ -208,6 +217,16 @@ protected void process() throws Exception {
     }
 
     String clientPackage = Strings.emptyToNull(options.get(CLIENT_PACKAGE));
+    String transport = options.get(TRANSPORT).toLowerCase();
+
+    TransportProtocol tp;
+    if (transport.equals("grpc")) {
+      tp = TransportProtocol.GRPC;
+    } else if (transport.equals("rest")) {
+      tp = TransportProtocol.HTTP;
+    } else {
+      throw new IllegalArgumentException("Unknown transport protocol: " + transport);
+    }
 
     GapicProductConfig productConfig =
         GapicProductConfig.create(
@@ -217,7 +236,8 @@ protected void process() throws Exception {
             protoPackage,
             clientPackage,
             language,
-            gRPCServiceConfig);
+            gRPCServiceConfig,
+            tp);
     if (productConfig == null) {
       ToolUtil.reportDiags(model.getDiagReporter().getDiagCollector(), true);
       return;

src/main/java/com/google/api/codegen/gapic/GapicGeneratorFactory.java

@@ -262,7 +262,7 @@ public static List<CodeGenerator<?>> create(
                   new JavaSurfaceTestTransformer<>(
                       javaTestPathMapper,
                       new JavaGapicSurfaceTransformer(javaTestPathMapper),
-                      "java/grpc_test.snip")));
+                      "java/test.snip")));
         }
       }
       return generators;