feat: gRPC support with CallGrpcTaskBuilder and related classes (#1353)

Signed-off-by: Matheus André <matheusandr2@gmail.com>

Author: matheusandre1

fluent/README.md

@@ -69,6 +69,108 @@ Workflow wf = WorkflowBuilder
 > [!NOTE]
 > We rename reserved keywords (`for`, `do`, `if`, `while`, `switch`, `try`) to safe identifiers (`forEach`, `tasks`, `when`, etc.).
 
+#### Call Tasks — HTTP, OpenAPI, gRPC
+
+The spec fluent DSL supports all three call task types defined by the specification:
+
+| Call Type | DSL Factory | Shortcut |
+|-----------|------------|----------|
+| HTTP | `call(http().GET().endpoint(...))` | `DSL.http()` |
+| OpenAPI | `call(openapi().document(...).operation(...))` | `DSL.openapi()` |
+| gRPC | `call(grpc().proto(...).service(...).method(...))` | `DSL.grpc()` |
+
+**HTTP call:**
+
+```java
+import static io.serverlessworkflow.fluent.spec.dsl.DSL.*;
+
+Workflow wf = WorkflowBuilder.workflow("myFlow", "myNs", "1.0")
+    .tasks(call(
+        http()
+          .GET()
+          .endpoint("https://petstore.swagger.io/v2/pet")
+    ))
+    .build();
+```
+
+**OpenAPI call:**
+
+```java
+Workflow wf = WorkflowBuilder.workflow("myFlow", "myNs", "1.0")
+    .tasks(call(
+        openapi()
+          .document("https://api.example.com/openapi.yaml")
+          .operation("getPetById")
+          .parameter("id", "42")
+    ))
+    .build();
+```
+
+**gRPC call:**
+
+```java
+Workflow wf = WorkflowBuilder.workflow("myFlow", "myNs", "1.0")
+    .tasks(call(
+        grpc()
+          .proto("workflows-samples/grpc/proto/person.proto")
+          .service("Person", "localhost", 5011)
+          .method("GetPerson")
+    ))
+    .build();
+```
+
+**gRPC call with arguments and authentication:**
+
+```java
+Workflow wf = WorkflowBuilder.workflow("myFlow", "myNs", "1.0")
+    .tasks(call(
+        grpc()
+          .proto("proto/contributors.proto", basic("user", "pass"))
+          .service("Contributors", "localhost", 5011)
+          .method("GetContributor")
+          .argument("github", "${ .github }")
+    ))
+    .build();
+```
+
+**gRPC call with a named task:**
+
+```java
+Workflow wf = WorkflowBuilder.workflow("myFlow", "myNs", "1.0")
+    .tasks(call(
+        "greet",
+        grpc()
+          .proto("proto/person.proto")
+          .service("Person", "localhost", 5011)
+          .method("GetPerson")
+    ))
+    .build();
+```
+
+##### `CallGrpcSpec` API Reference
+
+| Method | Description |
+|--------|-------------|
+| `proto(String uri)` | Sets the proto definition endpoint (file path or URI) |
+| `proto(String uri, AuthenticationConfigurer auth)` | Sets the proto endpoint with authentication; also applies the same authentication to the service configuration when no service-level authentication has been set yet |
+| `service(String name, String host)` | Sets the gRPC service name and host |
+| `service(String name, String host, int port)` | Sets the gRPC service name, host, and port |
+| `method(String method)` | Sets the gRPC method name to call |
+| `argument(String name, Object value)` | Adds a single method argument |
+| `arguments(Map<String, Object> args)` | Adds multiple method arguments |
+| `authentication(AuthenticationConfigurer auth)` | Sets or overrides the service-level authentication policy |
+
+You can also use the low-level `CallGrpcConfigurer` lambda directly:
+
+```java
+Workflow wf = WorkflowBuilder.workflow("f", "ns", "1")
+    .tasks(call((CallGrpcConfigurer) b -> b
+        .proto("proto/service.proto")
+        .service("Svc", "host")
+        .method("DoThing")))
+    .build();
+```
+
 ---
 
 ### 2. Func Fluent

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/BaseTaskItemListBuilder.java

@@ -45,6 +45,7 @@ public abstract class BaseTaskItemListBuilder<SELF extends BaseTaskItemListBuild
   protected final String TYPE_WAIT = "wait";
   protected final String TYPE_HTTP = "http";
   protected final String TYPE_OPENAPI = "openapi";
+  protected final String TYPE_GRPC = "grpc";
   protected final String TYPE_WORKFLOW = "workflow";
 
   private final List<TaskItem> list;

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/CallGrpcTaskBuilder.java

@@ -0,0 +1,35 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.spec;
+
+import io.serverlessworkflow.api.types.CallGRPC;
+import io.serverlessworkflow.api.types.GRPCArguments;
+import io.serverlessworkflow.fluent.spec.spi.CallGrpcTaskFluent;
+
+public class CallGrpcTaskBuilder extends TaskBaseBuilder<CallGrpcTaskBuilder>
+    implements CallGrpcTaskFluent<CallGrpcTaskBuilder> {
+
+  CallGrpcTaskBuilder() {
+    final CallGRPC callGRPC = new CallGRPC();
+    callGRPC.setWith(new GRPCArguments());
+    super.setTask(callGRPC);
+  }
+
+  @Override
+  public CallGrpcTaskBuilder self() {
+    return this;
+  }
+}

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/DoTaskBuilder.java

@@ -104,6 +104,12 @@ public DoTaskBuilder openapi(String name, Consumer<CallOpenAPITaskBuilder> items
     return this;
   }
 
+  @Override
+  public DoTaskBuilder grpc(String name, Consumer<CallGrpcTaskBuilder> itemsConfigurer) {
+    this.listBuilder().grpc(name, itemsConfigurer);
+    return this;
+  }
+
   @Override
   public DoTaskBuilder workflow(String name, Consumer<WorkflowTaskBuilder> itemsConfigurer) {
     this.listBuilder().workflow(name, itemsConfigurer);

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/TaskItemListBuilder.java

@@ -153,6 +153,21 @@ public TaskItemListBuilder openapi(
     return addTaskItem(new TaskItem(name, task));
   }
 
+  @Override
+  public TaskItemListBuilder grpc(String name, Consumer<CallGrpcTaskBuilder> itemsConfigurer) {
+    name = defaultNameAndRequireConfig(name, itemsConfigurer, TYPE_GRPC);
+
+    final CallGrpcTaskBuilder callGRPCBuilder = new CallGrpcTaskBuilder();
+    itemsConfigurer.accept(callGRPCBuilder);
+
+    final CallTask callTask = new CallTask();
+    callTask.setCallGRPC(callGRPCBuilder.build());
+    final Task task = new Task();
+    task.setCallTask(callTask);
+
+    return addTaskItem(new TaskItem(name, task));
+  }
+
   @Override
   public TaskItemListBuilder workflow(String name, Consumer<WorkflowTaskBuilder> itemsConfigurer) {
     name = defaultNameAndRequireConfig(name, itemsConfigurer, TYPE_WORKFLOW);

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/configurers/CallGrpcConfigurer.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.spec.configurers;
+
+import io.serverlessworkflow.fluent.spec.CallGrpcTaskBuilder;
+import java.util.function.Consumer;
+
+@FunctionalInterface
+public interface CallGrpcConfigurer extends Consumer<CallGrpcTaskBuilder> {}

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/dsl/CallGrpcSpec.java

@@ -0,0 +1,77 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.spec.dsl;
+
+import io.serverlessworkflow.fluent.spec.CallGrpcTaskBuilder;
+import io.serverlessworkflow.fluent.spec.configurers.AuthenticationConfigurer;
+import io.serverlessworkflow.fluent.spec.configurers.CallGrpcConfigurer;
+import io.serverlessworkflow.fluent.spec.spi.CallGrpcTaskFluent;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.function.Consumer;
+
+public final class CallGrpcSpec implements CallGrpcConfigurer {
+
+  private final List<Consumer<CallGrpcTaskFluent<?>>> steps = new ArrayList<>();
+
+  public CallGrpcSpec proto(String uri) {
+    steps.add(b -> b.proto(uri));
+    return this;
+  }
+
+  public CallGrpcSpec proto(String uri, AuthenticationConfigurer authenticationConfigurer) {
+    steps.add(b -> b.proto(uri, authenticationConfigurer));
+    return this;
+  }
+
+  public CallGrpcSpec service(String name, String host) {
+    steps.add(b -> b.service(name, host));
+    return this;
+  }
+
+  public CallGrpcSpec service(String name, String host, int port) {
+    steps.add(b -> b.service(name, host, port));
+    return this;
+  }
+
+  public CallGrpcSpec method(String method) {
+    steps.add(b -> b.method(method));
+    return this;
+  }
+
+  public CallGrpcSpec arguments(Map<String, Object> arguments) {
+    steps.add(b -> b.arguments(arguments));
+    return this;
+  }
+
+  public CallGrpcSpec argument(String name, Object value) {
+    steps.add(b -> b.argument(name, value));
+    return this;
+  }
+
+  public CallGrpcSpec authentication(AuthenticationConfigurer authenticationConfigurer) {
+    steps.add(b -> b.authentication(authenticationConfigurer));
+    return this;
+  }
+
+  @Override
+  public void accept(CallGrpcTaskBuilder builder) {
+    for (var s : steps) {
+      s.accept(builder);
+    }
+  }
+}

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/dsl/DSL.java

@@ -26,6 +26,7 @@
 import io.serverlessworkflow.fluent.spec.TimeoutBuilder;
 import io.serverlessworkflow.fluent.spec.TryTaskBuilder;
 import io.serverlessworkflow.fluent.spec.configurers.AuthenticationConfigurer;
+import io.serverlessworkflow.fluent.spec.configurers.CallGrpcConfigurer;
 import io.serverlessworkflow.fluent.spec.configurers.CallHttpConfigurer;
 import io.serverlessworkflow.fluent.spec.configurers.CallOpenAPIConfigurer;
 import io.serverlessworkflow.fluent.spec.configurers.ForEachConfigurer;
@@ -106,6 +107,10 @@ public static CallOpenAPISpec openapi() {
     return new CallOpenAPISpec();
   }
 
+  public static CallGrpcSpec grpc() {
+    return new CallGrpcSpec();
+  }
+
   public static WorkflowSpec workflow(String namespace, String name, String version) {
     return new WorkflowSpec().namespace(namespace).name(name).version(version);
   }
@@ -683,6 +688,14 @@ public static TasksConfigurer call(String name, CallOpenAPIConfigurer configurer
     return list -> list.openapi(name, configurer);
   }
 
+  public static TasksConfigurer call(CallGrpcConfigurer configurer) {
+    return list -> list.grpc(configurer);
+  }
+
+  public static TasksConfigurer call(String name, CallGrpcConfigurer configurer) {
+    return list -> list.grpc(name, configurer);
+  }
+
   /**
    * Create a {@link TasksConfigurer} that adds a {@code set} task using a low-level configurer.
    *

fluent/spec/src/main/java/io/serverlessworkflow/fluent/spec/spi/CallGrpcFluent.java

@@ -0,0 +1,28 @@
+/*
+ * Copyright 2020-Present The Serverless Workflow Specification Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.serverlessworkflow.fluent.spec.spi;
+
+import io.serverlessworkflow.fluent.spec.TaskBaseBuilder;
+import java.util.function.Consumer;
+
+public interface CallGrpcFluent<SELF extends TaskBaseBuilder<SELF>, LIST> {
+
+  LIST grpc(String name, Consumer<SELF> itemsConfigurer);
+
+  default LIST grpc(Consumer<SELF> itemsConfigurer) {
+    return this.grpc(null, itemsConfigurer);
+  }
+}