Add new gateway node-type

CMakeLists.txt

@@ -125,7 +125,10 @@ pkg_check_modules(NANOMSG IMPORTED_TARGET nanomsg)
 if(NOT NANOMSG_FOUND)
     pkg_check_modules(NANOMSG IMPORTED_TARGET libnanomsg>=1.0.0)
 endif()
-
+pkg_check_modules(GRPC IMPORTED_TARGET grpc grpc++)
+if (TARGET PkgConfig::GRPC)
+    set_property(TARGET PkgConfig::GRPC PROPERTY INTERFACE_COMPILE_OPTIONS "")
+endif()
 
 if (REDISPP_FOUND)
     file(READ "${REDISPP_INCLUDEDIR}/sw/redis++/tls.h" CONTENTS)
@@ -187,6 +190,7 @@ cmake_dependent_option(WITH_SRC                 "Build executables"
 cmake_dependent_option(WITH_TESTS               "Run tests"                                             "${WITH_DEFAULTS}" "TOPLEVEL_PROJECT" OFF)
 cmake_dependent_option(WITH_TOOLS               "Build auxilary tools"                                  "${WITH_DEFAULTS}" "TOPLEVEL_PROJECT" OFF)
 cmake_dependent_option(WITH_WEB                 "Build with internal webserver"                         "${WITH_DEFAULTS}" "LIBWEBSOCKETS_FOUND" OFF)
+cmake_dependent_option(WITH_GRPC                "Build with grpc api"                                   "${WITH_DEFAULTS}" "GRPC_FOUND" OFF)
 
 cmake_dependent_option(WITH_NODE_AMQP           "Build with amqp node-type"                             "${WITH_DEFAULTS}" "RABBITMQ_C_FOUND" OFF)
 cmake_dependent_option(WITH_NODE_CAN            "Build with can node-type"                              "${WITH_DEFAULTS}" "" OFF)
@@ -297,6 +301,7 @@ add_feature_info(SRC                    WITH_SRC                    "Build execu
 add_feature_info(TESTS                  WITH_TESTS                  "Run tests")
 add_feature_info(TOOLS                  WITH_TOOLS                  "Build auxilary tools")
 add_feature_info(WEB                    WITH_WEB                    "Build with internal webserver")
+add_feature_info(GRPC_API               WITH_GRPC                   "Build with gRPC API")
 
 add_feature_info(NODE_AMQP              WITH_NODE_AMQP              "Build with amqp node-type")
 add_feature_info(NODE_CAN               WITH_NODE_CAN               "Build with can node-type")

doc/openapi/components/schemas/config/nodes/_gateway.yaml

@@ -0,0 +1,7 @@
+# yaml-language-server: $schema=http://json-schema.org/draft-07/schema
+# SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
+# SPDX-License-Identifier: Apache-2.0
+---
+allOf:
+- $ref: ../node_obj.yaml
+- $ref: gateway.yaml

doc/openapi/components/schemas/config/nodes/gateway.yaml

@@ -0,0 +1,15 @@
+# yaml-language-server: $schema=http://json-schema.org/draft-07/schema
+# SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
+# SPDX-License-Identifier: Apache-2.0
+---
+allOf:
+- type: object
+  properties:
+    format:
+      $ref: ../format_spec.yaml
+    gateway_type:
+      type: string
+    address:
+      type: string
+
+- $ref: ../node.yaml

etc/examples/nodes/gateway.conf

@@ -0,0 +1,14 @@
+# SPDX-FileCopyrightText: 2014-2023 Institute for Automation of Complex Power Systems, RWTH Aachen University
+# SPDX-License-Identifier: Apache-2.0
+
+nodes = {
+    gateway_node = {
+        type = "gateway"
+
+        format = "protobuf"
+        #  API type
+        gateway_type = "gRPC"
+        # Address of remote server
+        address = "localhost:50051"
+    }
+}

flake.nix

@@ -119,6 +119,7 @@
 
         opendssc = pkgs.callPackage (nixDir + "/opendssc.nix") { };
         orchestra = pkgs.callPackage (nixDir + "/orchestra.nix") { };
+        grpc-server-reflection = pkgs.callPackage (nixDir + "/grpc_server_reflection.nix") { };
       };
     in
     {

include/villas/nodes/gateway.hpp

@@ -0,0 +1,59 @@
+/* Node type for API gateway.
+ *
+ * Author: Jitpanu Maneeratpongsuk <jitpanu.maneeratpongsuk@rwth-aachen.de>
+ * SPDX-FileCopyrightText: 2025 Institute for Automation of Complex Power Systems, RWTH Aachen University
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#pragma once
+
+#include <pthread.h>
+
+#include <villas/format.hpp>
+#include <villas/node.hpp>
+
+namespace villas {
+namespace node {
+
+// Forward declarations
+struct Sample;
+
+class GatewayNode : public Node {
+protected:
+  int parse(json_t *json) override;
+
+  int _read(struct Sample *smps[], unsigned cnt) override;
+  int _write(struct Sample *smps[], unsigned cnt) override;
+
+public:
+  GatewayNode(const uuid_t &id = {}, const std::string &name = "");
+  enum ApiType { gRPC };
+
+  struct Direction {
+    Sample *sample;
+    pthread_cond_t cv;
+    pthread_mutex_t mutex;
+    char *buf;
+    size_t buflen;
+    size_t wbytes;
+  };
+
+  Direction read, write;
+  std::string address;
+  ApiType type;
+
+  Format::Ptr formatter;
+
+  int prepare() override;
+
+  int check() override;
+
+  int start() override;
+
+  int stop() override;
+
+  ~GatewayNode();
+};
+
+} // namespace node
+} // namespace villas

lib/api/CMakeLists.txt

@@ -42,6 +42,20 @@ if(WITH_GRAPHVIZ)
     list(APPEND LIBRARIES PkgConfig::CGRAPH PkgConfig::GVC)
 endif()
 
+if (WITH_GRPC)
+    find_path(REFLECTION_INCLUDE_DIR
+        NAMES grpc/reflection/v1alpha/reflection.pb.cc
+    )
+    if (REFLECTION_INCLUDE_DIR)
+        list(APPEND API_SRC
+            requests/gateway/grpc.cpp
+            ${REFLECTION_INCLUDE_DIR}/grpc/reflection/v1alpha/reflection.pb.cc
+            ${REFLECTION_INCLUDE_DIR}/grpc/reflection/v1alpha/reflection.grpc.pb.cc
+        )
+        list(APPEND LIBRARIES PkgConfig::PROTOBUF PkgConfig::GRPC)
+    endif()
+endif()
+
 add_library(api STATIC ${API_SRC})
 target_include_directories(api PUBLIC ${INCLUDE_DIRS})
 target_link_libraries(api PUBLIC ${LIBRARIES})

lib/api/request.cpp

@@ -25,7 +25,7 @@ std::string Request::toString() {
 
 Request *RequestFactory::create(Session *s, const std::string &uri,
                                 Session::Method meth, unsigned long ct) {
-  s->logger->info("Lookup request handler for: uri={}", uri);
+  s->logger->debug("Lookup request handler for: uri={}", uri);
 
   for (auto *rf : plugin::registry->lookup<RequestFactory>()) {
     std::smatch mr;