add Logger::get_effective_level().

rclcpp/include/rclcpp/logger.hpp

@@ -170,6 +170,24 @@ class Logger
   RCLCPP_PUBLIC
   void
   set_level(Level level);
+
+  /// Get effective level for current logger.
+  /**
+   * The effective level is determined as the severity level of
+   * the logger if it is set, otherwise it is the first specified severity
+   * level of the logger's ancestors, starting with its closest ancestor.
+   * The ancestor hierarchy is signified by logger names being separated by dots:
+   * a logger named `x` is an ancestor of `x.y`, and both `x` and `x.y` are
+   * ancestors of `x.y.z`, etc.
+   * If the level has not been set for the logger nor any of its
+   * ancestors, the default level is used.
+   *
+   * \throws rclcpp::exceptions::RCLError if any error happens.
+   * \return Level for the current logger.
+   */
+  RCLCPP_PUBLIC
+  Level
+  get_effective_level() const;
 };
 
 }  // namespace rclcpp

rclcpp/src/rclcpp/logger.cpp

@@ -125,4 +125,18 @@ Logger::set_level(Level level)
   }
 }
 
+Logger::Level
+Logger::get_effective_level() const
+{
+  int logger_level = rcutils_logging_get_logger_effective_level(get_name());
+
+  if (logger_level < 0) {
+    exceptions::throw_from_rcl_error(
+      RCL_RET_ERROR, "Couldn't get logger level",
+      rcutils_get_error_state(), rcutils_reset_error);
+  }
+
+  return static_cast<Level>(logger_level);
+}
+
 }  // namespace rclcpp

rclcpp/test/rclcpp/test_logger.cpp

@@ -160,6 +160,50 @@ TEST(TestLogger, set_level) {
   EXPECT_EQ(RCUTILS_RET_OK, rcutils_logging_shutdown());
 }
 
+TEST(TestLogger, get_effective_level) {
+  ASSERT_EQ(RCUTILS_RET_OK, rcutils_logging_initialize());
+
+  rclcpp::Logger logger = rclcpp::get_logger("test_logger");
+  rclcpp::Logger child_logger = rclcpp::get_logger("test_logger.child");
+
+  // set child logger level unset to test effective level
+  child_logger.set_level(rclcpp::Logger::Level::Unset);
+
+  // default
+  EXPECT_EQ(rclcpp::Logger::Level::Info, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Info, child_logger.get_effective_level());
+
+  // unset
+  logger.set_level(rclcpp::Logger::Level::Unset);
+  EXPECT_EQ(rclcpp::Logger::Level::Info, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Info, child_logger.get_effective_level());
+
+  // debug
+  logger.set_level(rclcpp::Logger::Level::Debug);
+  EXPECT_EQ(rclcpp::Logger::Level::Debug, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Debug, child_logger.get_effective_level());
+
+  // info
+  logger.set_level(rclcpp::Logger::Level::Info);
+  EXPECT_EQ(rclcpp::Logger::Level::Info, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Info, child_logger.get_effective_level());
+
+  // warn
+  logger.set_level(rclcpp::Logger::Level::Warn);
+  EXPECT_EQ(rclcpp::Logger::Level::Warn, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Warn, child_logger.get_effective_level());
+
+  // error
+  logger.set_level(rclcpp::Logger::Level::Error);
+  EXPECT_EQ(rclcpp::Logger::Level::Error, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Error, child_logger.get_effective_level());
+
+  // fatal
+  logger.set_level(rclcpp::Logger::Level::Fatal);
+  EXPECT_EQ(rclcpp::Logger::Level::Fatal, logger.get_effective_level());
+  EXPECT_EQ(rclcpp::Logger::Level::Fatal, child_logger.get_effective_level());
+}
+
 TEST(TestLogger, get_logging_directory) {
   ASSERT_EQ(true, rcutils_set_env("HOME", "/fake_home_dir"));
   ASSERT_EQ(true, rcutils_set_env("USERPROFILE", nullptr));