Get parameter map (#575)

* Add in the ability to get parameters in a map.

Any parameters that have a "." in them will be considered to
be part of a "map" (though they can also be get and set
individually).  This PR adds two new template specializations
to the public node API so that it can take a map, and store
the list of values (so setting the parameter with a name of
"foo" and a key of "x" will end up with a parameter of "foo.x").
It also adds an API to get all of the keys corresponding to
a prefix, and returing that as a map (so a get of "foo" will
get all parameters that begin with "foo.").  Note that all
parameters within the map must have the same type, otherwise
an rclcpp::ParameterTypeException will be thrown.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Fix style problems pointed out by uncrustify/cpplint.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Move tests for set_parameter_if_not_set/get_parameter map to rclcpp.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Rename get_parameter -> get_parameters.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

* Add in documentation from review.

Signed-off-by: Chris Lalancette <clalancette@openrobotics.org>

rclcpp/CMakeLists.txt

@@ -401,6 +401,17 @@ if(BUILD_TESTING)
       "rcl")
     target_link_libraries(test_multi_threaded_executor ${PROJECT_NAME})
   endif()
+
+  ament_add_gtest(test_local_parameters test/test_local_parameters.cpp)
+  if(TARGET test_local_parameters)
+    target_include_directories(test_local_parameters PUBLIC
+      ${rcl_interfaces_INCLUDE_DIRS}
+      ${rmw_INCLUDE_DIRS}
+      ${rosidl_generator_cpp_INCLUDE_DIRS}
+      ${rosidl_typesupport_cpp_INCLUDE_DIRS}
+    )
+    target_link_libraries(test_local_parameters ${PROJECT_NAME})
+  endif()
 endif()
 
 ament_package(

rclcpp/include/rclcpp/node.hpp

@@ -279,6 +279,20 @@ public:
     const std::string & name,
     const ParameterT & value);
 
+  /// Set a map of parameters with the same prefix.
+  /**
+   * For each key in the map, a parameter with a name of "name.key" will be set
+   * to the value in the map.
+   *
+   * \param[in] name The prefix of the parameters to set.
+   * \param[in] values The parameters to set in the given prefix.
+   */
+  template<typename MapValueT>
+  void
+  set_parameters_if_not_set(
+    const std::string & name,
+    const std::map<std::string, MapValueT> & values);
+
   RCLCPP_PUBLIC
   std::vector<rclcpp::Parameter>
   get_parameters(const std::vector<std::string> & names) const;
@@ -305,6 +319,24 @@ public:
   bool
   get_parameter(const std::string & name, ParameterT & parameter) const;
 
+  /// Assign the value of the map parameter if set into the values argument.
+  /**
+   * Parameter names that are part of a map are of the form "name.member".
+   * This API gets all parameters that begin with "name", storing them into the
+   * map with the name of the parameter and their value.
+   * If there are no members in the named map, then the "values" argument is not changed.
+   *
+   * \param[in] name The prefix of the parameters to get.
+   * \param[out] values The map of output values, with one std::string,MapValueT
+   *                    per parameter.
+   * \returns true if values was changed, false otherwise
+   */
+  template<typename MapValueT>
+  bool
+  get_parameters(
+    const std::string & name,
+    std::map<std::string, MapValueT> & values) const;
+
   /// Get the parameter value, or the "alternative value" if not set, and assign it to "value".
   /**
    * If the parameter was not set, then the "value" argument is assigned

rclcpp/include/rclcpp/node_impl.hpp

@@ -224,6 +224,28 @@ Node::set_parameter_if_not_set(
   }
 }
 
+// this is a partially-specialized version of set_parameter_if_not_set above,
+// where our concrete type for ParameterT is std::map, but the to-be-determined
+// type is the value in the map.
+template<typename MapValueT>
+void
+Node::set_parameters_if_not_set(
+  const std::string & name,
+  const std::map<std::string, MapValueT> & values)
+{
+  std::vector<rclcpp::Parameter> params;
+
+  for (const auto & val : values) {
+    std::string param_name = name + "." + val.first;
+    rclcpp::Parameter parameter;
+    if (!this->get_parameter(param_name, parameter)) {
+      params.push_back(rclcpp::Parameter(param_name, val.second));
+    }
+  }
+
+  this->set_parameters(params);
+}
+
 template<typename ParameterT>
 bool
 Node::get_parameter(const std::string & name, ParameterT & value) const
@@ -237,6 +259,26 @@ Node::get_parameter(const std::string & name, ParameterT & value) const
   return result;
 }
 
+// this is a partially-specialized version of get_parameter above,
+// where our concrete type for ParameterT is std::map, but the to-be-determined
+// type is the value in the map.
+template<typename MapValueT>
+bool
+Node::get_parameters(
+  const std::string & name,
+  std::map<std::string, MapValueT> & values) const
+{
+  std::map<std::string, rclcpp::Parameter> params;
+  bool result = node_parameters_->get_parameters_by_prefix(name, params);
+  if (result) {
+    for (const auto & param : params) {
+      values[param.first] = param.second.get_value<MapValueT>();
+    }
+  }
+
+  return result;
+}
+
 template<typename ParameterT>
 bool
 Node::get_parameter_or(

rclcpp/include/rclcpp/node_interfaces/node_parameters.hpp

@@ -89,6 +89,13 @@ public:
     const std::string & name,
     rclcpp::Parameter & parameter) const;
 
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  get_parameters_by_prefix(
+    const std::string & prefix,
+    std::map<std::string, rclcpp::Parameter> & parameters) const;
+
   RCLCPP_PUBLIC
   virtual
   std::vector<rcl_interfaces::msg::ParameterDescriptor>

rclcpp/include/rclcpp/node_interfaces/node_parameters_interface.hpp

@@ -15,6 +15,7 @@
 #ifndef RCLCPP__NODE_INTERFACES__NODE_PARAMETERS_INTERFACE_HPP_
 #define RCLCPP__NODE_INTERFACES__NODE_PARAMETERS_INTERFACE_HPP_
 
+#include <map>
 #include <string>
 #include <vector>
 
@@ -89,6 +90,20 @@ public:
     const std::string & name,
     rclcpp::Parameter & parameter) const = 0;
 
+  /// Get all parameters that have the specified prefix into the parameters map.
+  /*
+   * \param[in] prefix the name of the prefix to look for.
+   * \param[out] parameters a map of parameters that matched the prefix.
+   * \return true if any parameters with the prefix exists on the node, or
+   * \return false otherwise.
+   */
+  RCLCPP_PUBLIC
+  virtual
+  bool
+  get_parameters_by_prefix(
+    const std::string & prefix,
+    std::map<std::string, rclcpp::Parameter> & parameters) const = 0;
+
   RCLCPP_PUBLIC
   virtual
   std::vector<rcl_interfaces::msg::ParameterDescriptor>

rclcpp/src/rclcpp/node_interfaces/node_parameters.cpp

@@ -283,6 +283,27 @@ NodeParameters::get_parameter(
   }
 }
 
+bool
+NodeParameters::get_parameters_by_prefix(
+  const std::string & prefix,
+  std::map<std::string, rclcpp::Parameter> & parameters) const
+{
+  std::string prefix_with_dot = prefix + ".";
+  bool ret = false;
+
+  std::lock_guard<std::mutex> lock(mutex_);
+
+  for (const auto & param : parameters_) {
+    if (param.first.find(prefix_with_dot) == 0 && param.first.length() > prefix_with_dot.length()) {
+      // Found one!
+      parameters[param.first.substr(prefix_with_dot.length())] = param.second;
+      ret = true;
+    }
+  }
+
+  return ret;
+}
+
 std::vector<rcl_interfaces::msg::ParameterDescriptor>
 NodeParameters::describe_parameters(const std::vector<std::string> & names) const
 {

rclcpp/test/test_local_parameters.cpp

@@ -0,0 +1,71 @@
+// Copyright 2018 Open Source Robotics Foundation, Inc.
+//
+// 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.
+
+#include <cstdio>
+#include <map>
+#include <string>
+
+#include "gtest/gtest.h"
+
+#include "rclcpp/rclcpp.hpp"
+
+TEST(test_local_parameters, set_parameter_if_not_set) {
+  auto node = rclcpp::Node::make_shared("test_local_parameters_set_parameter_if_not_set");
+
+  {
+    // try to set a map of parameters
+    std::map<std::string, double> bar_map{
+      {"x", 0.5},
+      {"y", 1.0},
+    };
+    node->set_parameters_if_not_set("bar", bar_map);
+    double bar_x_value;
+    ASSERT_TRUE(node->get_parameter("bar.x", bar_x_value));
+    EXPECT_EQ(bar_x_value, 0.5);
+    double bar_y_value;
+    ASSERT_TRUE(node->get_parameter("bar.y", bar_y_value));
+    EXPECT_EQ(bar_y_value, 1.0);
+    std::map<std::string, double> new_map;
+    ASSERT_TRUE(node->get_parameters("bar", new_map));
+    ASSERT_EQ(new_map.size(), 2U);
+    EXPECT_EQ(new_map["x"], 0.5);
+    EXPECT_EQ(new_map["y"], 1.0);
+  }
+
+  {
+    // try to get a map of parameters that doesn't exist
+    std::map<std::string, double> no_exist_map;
+    ASSERT_FALSE(node->get_parameters("no_exist", no_exist_map));
+  }
+
+  {
+    // set parameters for a map with different types, then try to get them back as a map
+    node->set_parameter_if_not_set("baz.x", 1.0);
+    node->set_parameter_if_not_set("baz.y", "hello");
+    std::map<std::string, double> baz_map;
+    EXPECT_THROW(node->get_parameters("baz", baz_map), rclcpp::ParameterTypeException);
+  }
+}
+
+int main(int argc, char ** argv)
+{
+  ::setvbuf(stdout, NULL, _IONBF, BUFSIZ);
+
+  // NOTE: use custom main to ensure that rclcpp::init is called only once
+  rclcpp::init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  int ret = RUN_ALL_TESTS();
+  rclcpp::shutdown();
+  return ret;
+}