Use singleton for static executor in the rosbag2_py::Recorder

Signed-off-by: Michael Orlov <[email protected]>

rosbag2_py/src/rosbag2_py/_transport.cpp

@@ -190,16 +190,28 @@ class Player
 class Recorder
 {
 private:
-  static std::unique_ptr<rclcpp::executors::SingleThreadedExecutor> exec_;
+  using ExecutorT = rclcpp::executors::SingleThreadedExecutor;
+  static std::unique_ptr<ExecutorT, void (*)(ExecutorT *)> & get_executor_instance()
+  {
+    static std::unique_ptr<ExecutorT, void (*)(ExecutorT *)> executor(
+      new ExecutorT(),
+      [](ExecutorT * exec_ptr) {
+        delete exec_ptr;
+        rclcpp::shutdown();
+      }
+    );
+    return executor;
+  }
   std::shared_ptr<rosbag2_transport::Recorder> recorder_;
 
 public:
   Recorder()
   {
     auto init_options = rclcpp::InitOptions();
     init_options.shutdown_on_signal = false;
-    rclcpp::init(0, nullptr, init_options, rclcpp::SignalHandlerOptions::None);
-    exec_ = std::make_unique<rclcpp::executors::SingleThreadedExecutor>();
+    if (!rclcpp::ok()) {
+      rclcpp::init(0, nullptr, init_options, rclcpp::SignalHandlerOptions::None);
+    }
     std::signal(
       SIGTERM, [](int /* signal */) {
         rosbag2_py::Recorder::cancel();
@@ -210,10 +222,7 @@ class Recorder
       });
   }
 
-  virtual ~Recorder()
-  {
-    rclcpp::shutdown();
-  }
+  virtual ~Recorder() = default;
 
   void record(
     const rosbag2_storage::StorageOptions & storage_options,
@@ -229,33 +238,35 @@ class Recorder
       std::move(writer), storage_options, record_options, node_name);
     recorder_->record();
 
-    exec_->add_node(recorder_);
-    // Release the GIL for long-running record, so that calling Python code can use other threads
-    {
+    get_executor_instance()->add_node(recorder_);
+    try {
+      // Release the GIL for long-running record, so that calling Python code can use other threads
       py::gil_scoped_release release;
       while (!exit_) {
-        exec_->spin_all(std::chrono::milliseconds(30));
+        get_executor_instance()->spin_all(std::chrono::milliseconds(30));
       }
       if (recorder_) {
         recorder_->stop();
         // Need to spin once to be able to send notifications about bag split and close
-        exec_->spin_some(std::chrono::milliseconds(30));
+        get_executor_instance()->spin_some(std::chrono::milliseconds(30));
       }
+    } catch (...) {
+      get_executor_instance()->remove_node(recorder_);
     }
+    get_executor_instance()->remove_node(recorder_);
   }
 
   static void cancel()
   {
     exit_ = true;
-    if (exec_) {
-      exec_->cancel();
+    if (get_executor_instance()) {
+      get_executor_instance()->cancel();
     }
   }
 
   static std::atomic_bool exit_;
 };
 
-std::unique_ptr<rclcpp::executors::SingleThreadedExecutor> Recorder::exec_;
 std::atomic_bool Recorder::exit_{false};
 
 // Return a RecordOptions struct with defaults set for rewriting bags.