Add arguments to configure number of threads

rclcpp_components/src/component_container_mt.cpp

@@ -21,8 +21,52 @@
 int main(int argc, char * argv[])
 {
   /// Component container with a multi-threaded executor.
-  rclcpp::init(argc, argv);
-  auto exec = std::make_shared<rclcpp::executors::MultiThreadedExecutor>();
+  auto vargv = rclcpp::init_and_remove_ros_arguments(argc, argv);
+  size_t number_of_threads{0};
+  rclcpp::Logger logger{rclcpp::get_logger("component_container_mt")};
+
+  if (vargv.size() > 1) {
+    for (auto itr = vargv.begin() + 1; itr != vargv.end(); ++itr) {
+      if (*itr == "--help" || *itr == "-h") {
+        RCLCPP_INFO_STREAM(
+          logger,
+          "Usage: component_container_mt --thread-num <number of thread>");
+        return 0;
+      } else if (*itr == "--thread-num" || *itr == "-t") {
+        if (itr == vargv.end() - 1) {
+          RCLCPP_ERROR_STREAM(
+            logger, "Empty thread number" << std::endl <<
+              "Usage: component_container_mt --thread-num <number of thread>");
+          return 0;
+        }
+        try {
+          const auto arg_number_of_threads{std::stoi(*(itr + 1))};
+          if (arg_number_of_threads > 0) {
+            number_of_threads = static_cast<size_t>(arg_number_of_threads);
+            RCLCPP_INFO_STREAM(logger, "Number of threads: " << number_of_threads);
+          } else if (arg_number_of_threads < 0) {
+            RCLCPP_ERROR_STREAM(logger, "Number of threads is minus: " << *(itr + 1));
+            return 0;
+          }
+          ++itr;
+        } catch (const std::invalid_argument & ex) {
+          RCLCPP_ERROR_STREAM(logger, "Invalid number of threads: " << *(itr + 1));
+          return 0;
+        } catch (const std::out_of_range & ex) {
+          RCLCPP_ERROR_STREAM(logger, "Number of threads is out of range: " << *(itr + 1));
+          return 0;
+        }
+      } else {
+        RCLCPP_ERROR_STREAM(
+          logger, "Invalid argument" << std::endl <<
+            "Usage: component_container_mt --thread-num <number of thread>");
+        return 0;
+      }
+    }
+  }
+
+  auto exec = std::make_shared<rclcpp::executors::MultiThreadedExecutor>(
+    rclcpp::ExecutorOptions(), number_of_threads);
   auto node = std::make_shared<rclcpp_components::ComponentManager>(exec);
   exec->add_node(node);
   exec->spin();