The names which are used as keys in the values map have the prefix removed. Returns current time from the time source specified by clock_type. Note that entities which use absolute names are not affected by any namespaces, neither the normal node namespace nor any sub-namespace. This method will result in any callback registered with add_on_set_parameters_callback to be called, once for each parameter. In all cases, the parameter is never set or declared within the node. However, if the namespace is an empty string, then no leading '.' But after that, any change to any parameter won't be taken into account. Return the topic endpoint information about publishers on a given topic. Can you explain more? rclcpp provides the standard C++ API for interacting with ROS 2. The updated values can include unsetting the value. If, at run-time, the user has provided an initial value then it will be set in this method, otherwise the given default_value will be set. Please start posting anonymously - your entry will be published after you log in or create a new account. From reading a long issue involving some 2 booleans with undeclared_auto_param_something_something and another boolean I just got that you always should declare your params, but this example doesn't do that? If that callback prevents the initial value for any parameter from being set then rclcpp::exceptions::InvalidParameterValueException is thrown. Return the Node's internal NodeWaitablesInterface implementation. topic_name may be a relative, private, or fully qualified topic name. Behaves like set_parameter, except that it sets multiple parameters, failing all if just one of the parameters are unsuccessfully set. remove_on_set_parameters_callback(scoped_callback.get()). Set one or more parameters, one at a time. Return the Node's internal NodeParametersInterface implementation. DDS) apps). This method will not cause a callback registered with add_on_set_parameters_callback to be called. Return the Node's internal NodeClockInterface implementation. Depending on your use case each different one has tradeoffs. That means that we'd have to change the signature of the parameter callbacks again. This namespace is the "node's" namespace, and therefore is not affected by any sub-namespace's that may affect entities created with this instance. The names of the parameters to be retrieved. rcl_interfaces::msg::SetParametersResult rclcpp::Node::set_parameter. if the sub-namespace is absolute, i.e. It consists of these main components: Node rclcpp::Node rclcpp/node.hpp Publisher rclcpp::Node::create_publisher () rclcpp::Publisher rclcpp::Publisher::publish () rclcpp/publisher.hpp Subscription rclcpp::Node::create_subscription () If the parameter has not been declared, then this method may throw the rclcpp::exceptions::ParameterNotDeclaredException exception. And by seeing the example in the documentation, we could conclude that the on set parameter callback could only filter an invalid parameter by rejecting it. if it starts with a leading '/'. The list of parameter names to get the types. By clicking Sign up for GitHub, you agree to our terms of service and Support for pre-set and post-set parameter callback. This may be done by using this method, create_sub_node(). const rcl_interfaces::msg::ParameterDescriptor &. The order of the callback is the reverse from the registration order. foo is std::vector. If you're going to be checking more than one parameter, the listing is likely valuable. The returned sub-namespace is either the accumulated sub-namespaces which were given to one-to-many create_sub_node() calls, or an empty string if this is an original node instance, i.e. GitHub What is set_on_parameters_set_callback doing? Modify Parameters On Set Parameter Callback. It should be possible to register it before or after the parameters are declared. Resetting or letting the smart pointer go out of scope after calling remove_on_set_parameters_callback is not a problem. as_bool () bool rclcpp::Parameter::as_bool ( ) const as_int () int64_t rclcpp::Parameter::as_int ( ) const The name expansion is naive, so if you set the namespace to be "foo. We didn't provide the specific API to check if a parameter exists. if the allocation of the OnSetParametersCallbackHandle fails. Add a callback for when parameters are being set. It will provide an API that can atomically update a set of values such that if any of the values fail validation, none of the values are set. Given a list of parameter names, it will request an update of the values subject to validation of the values. If undeclared parameters are allowed, then a default initialized descriptor will be returned. [rclcpp] How do you specify Subscriber queue_size? Already on GitHub? That way you wouldn't even have to write a parameter callback to accomplish this. rclcpp::Event::SharedPtr rclcpp::Node::get_graph_event, rclcpp::Clock::SharedPtr rclcpp::Node::get_clock, rclcpp::Clock::ConstSharedPtr rclcpp::Node::get_clock, rclcpp::node_interfaces::NodeBaseInterface::SharedPtr rclcpp::Node::get_node_base_interface, rclcpp::node_interfaces::NodeClockInterface::SharedPtr rclcpp::Node::get_node_clock_interface, rclcpp::node_interfaces::NodeGraphInterface::SharedPtr rclcpp::Node::get_node_graph_interface, rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr rclcpp::Node::get_node_logging_interface, rclcpp::node_interfaces::NodeTimersInterface::SharedPtr rclcpp::Node::get_node_timers_interface, rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr rclcpp::Node::get_node_topics_interface, rclcpp::node_interfaces::NodeServicesInterface::SharedPtr rclcpp::Node::get_node_services_interface, rclcpp::node_interfaces::NodeWaitablesInterface::SharedPtr rclcpp::Node::get_node_waitables_interface, rclcpp::node_interfaces::NodeParametersInterface::SharedPtr rclcpp::Node::get_node_parameters_interface, rclcpp::node_interfaces::NodeTimeSourceInterface::SharedPtr rclcpp::Node::get_node_time_source_interface, rclcpp::Node::SharedPtr rclcpp::Node::create_sub_node. Undeclare a previously declared parameter. I am also working on some improvements right now so that you can have read-only parameters. RvizQt, 11, gazebo rcl_interfaces::msg::ParameterDescriptor rclcpp::Node::describe_parameter, if the number of described parameters is more than one. A sub-node (short for subordinate node) is an instance of this class which has been created using an existing instance of this class, but which has an additional sub-namespace (short for subordinate namespace) associated with it. Or in this example how come that the parameter doesn't need to be declared? Return a map of existing topic names to list of topic types. Yes that's exactly what i means, as described by @clalancette. Return the Node's internal NodeBaseInterface implementation. With parameters you can already change the configuration of the node at runtime. When the no_mangle parameter is false, the provided topic_name should follow ROS topic name conventions. ( rclcpp callback parameter version for Cpp) Initialization Starter code What happens if you change a parameter with no callback Add an rclpy parameter callback The code Testing - get all modified params and print them Update class attributes in callback Remove parameters callback Process data inside the rclpy callback Execute an action Parameters are set in the order they are given within the input vector. And you can use get_parameter (s) to get the rclcpp::Parameter for it, and on that class there are as_*_array () methods: https://github.com/ros2/rclcpp/blob/a. Changelog for package rclcpp 17.1.0 (2022-11-02) MultiThreadExecutor number of threads is at least 2+ in default. The problem is that I don't think we can have function signatures with both const and non-const (C++ doesn't know which one to call). The name of the parameter to check for being declared. As an alternative, the smart pointer can be reset: Supposing that scoped_callback was the only owner. const char* rclcpp::Node::get_fully_qualified_name, rclcpp::CallbackGroup::SharedPtr rclcpp::Node::create_callback_group. The map contains default values for parameters. Or is 'foo' of the rclcpp::Parameter type? rclcpp::node_interfaces::OnSetParametersCallbackHandle, rclcpp::node_interfaces::NodeParametersInterface::OnParametersSetCallbackType, rclcpp::Node::OnParametersSetCallbackType, rclcpp::Node::OnSetParametersCallbackHandle, rclcpp::exceptions::InvalidParameterValueException, rclcpp::exceptions::ParameterAlreadyDeclaredException, rclcpp::exceptions::InvalidParametersException, rclcpp::exceptions::InvalidParameterTypeException, https://en.cppreference.com/w/cpp/language/lifetime, https://herbsutter.com/2008/01/01/gotw-88-a-candidate-for-the-most-important-const/, https://www.youtube.com/watch?v=uQyT-5iWUow, rclcpp::exceptions::ParameterNotDeclaredException, rclcpp::exceptions::ParameterImmutableException, rclcpp::NodeOptions::allow_undeclared_parameters, rclcpp::exceptions::ParameterModifiedInCallbackException, rclcpp::node_interfaces::NodeClock::get_clock, template, typename PublisherT = rclcpp::Publisher>, template, typename CallbackMessageT = typename rclcpp::subscription_traits::has_message_type::type, typename SubscriptionT = rclcpp::Subscription, typename MessageMemoryStrategyT = rclcpp::message_memory_strategy::MessageMemoryStrategy< CallbackMessageT, AllocatorT >>, template, rcl_interfaces::msg::ListParametersResult, Wait for a graph event to occur by waiting on an, rclcpp::node_interfaces::NodeBaseInterface::SharedPtr, rclcpp::node_interfaces::NodeClockInterface::SharedPtr, rclcpp::node_interfaces::NodeGraphInterface::SharedPtr, rclcpp::node_interfaces::NodeLoggingInterface::SharedPtr, rclcpp::node_interfaces::NodeTimersInterface::SharedPtr, rclcpp::node_interfaces::NodeTopicsInterface::SharedPtr, rclcpp::node_interfaces::NodeServicesInterface::SharedPtr, rclcpp::node_interfaces::NodeWaitablesInterface::SharedPtr, rclcpp::node_interfaces::NodeParametersInterface::SharedPtr, rclcpp::node_interfaces::NodeTimeSourceInterface::SharedPtr. the topic_name on which to find the publishers. We don't have it in the demos but there are tests covering it you can use as an example, here. If a parameter fails to be set due to any other reason, like being rejected by the user's callback (basically any reason other than not having been declared beforehand), then that is reflected in the corresponding SetParametersResult in the vector returned by this function. The registered callbacks are called when a parameter is set. I have another case of a driver for an experimental camera that is even more complex. If you don't end up rolling it into that PR, please ping me and I'll try to make one. Return the parameter descriptor for the given parameter name. Note: in this particular case the driver SDK immediately returns the adjusted value which simplifies the logic. If setting a parameter fails due to not being declared, then the parameters which have already been set will stay set, and no attempt will be made to set the parameters which come after. template, template, template, template. This method is used to declare that a parameter exists on this node. The given Event must be acquire through the get_graph_event() method. I don't think anyone is currently working on this, so help here would be appreciated. you tried setting the frame rate to 40fps, but the driver knocked it back down to 33.7fps)? rcl_interfaces::msg::SetParametersResult result; Encapsulation of Quality of Service settings. Neither is hacking it the way I currently do by starting a timer inside the parameter callback handler to defer the modification of the parameter: So I would say that this case is probably beyond the scope of what a set_parameter_callback() can do (at least, in the current design). link Comments Is there a way to achieve this by just using this->declare_parameter<float> ("foo", 15.0); this->get_parameter ("foo", foo); syntax? If the parameter has not been declared, it will not attempt to coerce the value into the requested type, as it is known that the type is not set. but what if i set the parameter to be 101.0, using the current on_set_parameter_callback() behavior, then i could only reject it. To avoid this, use the declare_parameter() method which returns an rclcpp::ParameterValue instead. It looks like the documentation is not complete. this->get_parameter("foo", foo); syntax? Like set_parameter and set_parameters, this method may throw an rclcpp::exceptions::ParameterNotDeclaredException exception if any of the parameters to be set have not first been declared. There was some work done on lists in parameters this cycle, but I don't know the state off-hand, let me look it up. For removing it, use set_on_parameters_set_callback(nullptr). If the parameter was declared, and therefore has a value, then it is assigned into the "parameter" argument of this method. Even a std::clamp inside the on_set_parameter_callback won't work as the parameter itself is immutable. With the current callback, it is entirely possible to clamp a value as you set it. If you don't do that, you won't be able to access it and you'll get an error instead (rclcpp::exceptions::ParameterNotDeclaredException). Get the parameter values for all parameters that have a given prefix. If undeclared parameters are allowed, then the parameter is implicitly declared with the default parameter meta data before being set. rcl_interfaces::msg::ListParametersResult rclcpp::Node::list_parameters. For the slightly different case than what @tfoote linked to, here's how to get a single parameter as an array of values. With parameters you can already change the configuration of the node at runtime. Using a validator before updating the parameters is all nice and well if validation can be done beforehand. The sub-namespace should be relative, and an exception will be thrown if the sub-namespace is absolute, i.e. More Node is the single point of entry for creating publishers and subscribers. Have a question about this project? If the callback prevents the parameter from being set, then, as mentioned before, it will be reflected in the corresponding SetParametersResult that is returned, but no exception will be thrown. starts with a leading '/'. For each key in the map, a parameter with a name of "namespace.key" will be set to the value in the map. The sub-namespace will extend the node's namespace for the purpose of creating additional entities, such as Publishers, Subscriptions, Service Clients and Servers, and so on. To the ROS2 Related Top Page ROS2 Lecture: Beginner -ROS1 style- [Previous: ROS2 publisher/subscriber using original messages: Beginner -ROS1 style-] [Next:Minimum configuration parameter:ROS2 -ROS1 style-] Here, we create a service and client program. remove_on_set_parameters_callback can also be used. As explained in the add_on_set_parameters_callback() documentation: The callback signature is designed to allow handling of any of the above set_parameter* or declare_parameter* methods, and so it takes a const reference to a vector of parameters to be set, and returns an instance of rcl_interfaces::msg::SetParametersResult to indicate whether or not the parameter should be set or not, and if not why. The node from which a new sub-node is created. Return the Node's internal NodeTopicsInterface implementation. If the type of the default value, and therefore also the type of return value, differs from the initial value provided in the node options, then a rclcpp::exceptions::InvalidParameterTypeException may be thrown. wouldn't it be better if i could accept it in condition that the parameter value is clamped to 100.0? Note that the callback is called when declare_parameter() and its variants are called, and so you cannot assume the parameter has been set before this callback, so when checking a new value against the existing one, you must account for the case where the parameter is not yet set. i have a parameter that should only accept the double value of 0.0 to 100.0, but what if i accidently set the parameter to be 101.0. i guess that is the setter's responsibility, since setter sets the parameter which is out of range? Incorrect Security Information - Docker GUI, How to get an array of parameters with rclcpp, get_parameter returning an ParameterVariant, Creative Commons Attribution Share Alike 3.0. @clalancette thanks, works for me! Delete a handler returned by add_on_set_parameters_callback. We recently merged this feature (made by @ayrton04), see: Looks like there's no documentation yet, but there is an example of setting: And you can use get_parameter(s) to get the rclcpp::Parameter for it, and on that class there are as_*_array() methods: Is there a way to achieve this by just using this->declare_parameter("foo", 15.0); I have another case of a driver for an experimental camera that is even more complex. Get the parameter value, or the "alternative_value" if not set, and assign it to "parameter". Create a new node with the specified name. If the callback prevents the parameter from being set, then it will be reflected in the SetParametersResult that is returned, but no exception will be thrown. using rclcpp::Node::OnParametersSetCallbackType = rclcpp::node_interfaces::NodeParametersInterface::OnParametersSetCallbackType Constructor & Destructor Documentation Node () [1/3] Create a new node with the specified name. tf::createQuaternionFromYaw equivalent in ros2, Define custom messages in python package (ROS2), Check if ROS2 Parameters Exist with RCLCPP, there doesn't seem to be a way to check if a parameter exists, Creative Commons Attribution Share Alike 3.0. In ROS 2, this interface had to become more complex to cope with a larger set of configuration options, an ambiguity in remapping rules and parameter assignment syntax (as a result of the leading underscore name convention for hidden resources), a one-to-many relationship between executables and nodes, to name a few. But I'm running into cases where a driver will adjust parameters that have been set, based on rules that are either too complex to reasonably encode, or are not documented at all. Return the number of publishers that are advertised on a given topic. That means that we'd have to change the signature of the parameter callbacks again. rclcpp: ROS Client Library for C++ rclcpp provides the canonical C++ API for interacting with ROS. ROS2 rclcpp Parameter Callback [Tutorial] In this ROS2 tutorial I will show you how to use an rclcpp parameter callback, so you can dynamically change parameters' values while a node is alive. In the case for the camera FPS, if the hardware only supports up to 100 Hz, but the parameter input was 1000 Hz (or negative), reject it at this stage. Here is a simple way to declare and get a vector of integers in Galactic: This shows how to declare the parameter. Register a callback to be called anytime a parameter is about to be changed. We also support arrays of primatives. I can declare and get parameters from YAML for 'ros_st' and 'ros_i' easily by: this->declare_parameter("ros_st", "Hello"); this->declare_parameter("ros_i", 0); this->get_parameter("ros_st", _st); this->get_parameter("ros_i", _n); But, I have no idea how to declare 'ros_vec' and get the parameters. I'm sorry, I haven't reached this thread for a while. There are two different things here: My suggestion for now is to implement the first one. That is, my parameterCallback() looks something like: But I think what you are trying to do is something more like: @threeal Can you confirm that this is the use case you are trying to support? when i accept it, the parameter would simply changed from double to integer, and it would be considered bad. The name of the parameter to be undeclared. Well occasionally send you account related emails. That "normal" node instance may, however, be used to create further instances of this class, based on the original instance, which have an additional sub-namespace associated with them. parameter /position -> [1.0, 1.0, 0.0])? Parameters Exceptions InvalidNamespaceError if the namespace is invalid Node () [2/3] Sorry I thought you wanted to list multiple parameters. If a callback tries to do any of the latter things, rclcpp::exceptions::ParameterModifiedInCallbackException will be thrown. In ROS2, there doesn't seem to be a way to check if a parameter exists directly without attempting to get the value of the parameter. Considered the following scenario, i have a parameter that should only accept the double value of 0.0 to 100.0. if i set the parameter with double value between 0.0 to 100.0, then it would be fine. Additional options to control creation of the node. not a sub-node. rclcpp parameter callback Going further with ROS2 params Setup code and declare ROS2 params with rclcpp Before you use a ROS2 param in your Cpp code, you must declare it. When I've used this in the past, I've always had a separate member variable internal to the class that I set. Yes, that is the default. joint_state_publisher_guirobot_state_publisher: joint_state_publisher_guijoint_state_publisherjoint_state_publisher_guiURDF , robot_state_publisher, robot_descriptionparameters. If you want to do more the descriptions are valuable. The return value of this class is a copy of the member of a ParameterValue which is returned by the other version of declare_parameter(). the namespace of the node associated with the name. How ROS 2 params work ROS 2 nodes first declare the parameters they can accept (1), then read the parameter values passed to them during startup - via the command line interface (2) or a YAML configuration file (3) - to determine their behavior. The syntax has been getting easier over time. Either all of the parameters are set or none of them are set. Usage #include "rclcpp/rclcpp.hpp" allows use of the most common elements of the ROS 2 system. Using a validator before updating the parameters is all nice and well if validation can be done beforehand. Note also that the fully qualified node name is unaffected by a sub-namespace. The namespace in which to declare the parameters. if the requested type does not match the value of the parameter which is stored. An optional, custom description for the parameter. Get value of parameter using rclcpp::ParameterType as template argument. Return the NodeOptions used when creating this node. Use get_effective_namespace() to get the full namespace used by entities. Like the version of get_parameter() which returns a bool, this method will not throw the rclcpp::exceptions::ParameterNotDeclaredException exception. The latter, one parameter name, which is why I figured get_parameters wouldn't work. Return the topic endpoint information about subscriptions on a given topic. The problem with const reference is we cannot modify the value of the parameters to be set inside the on set parameter callback. Like get_parameters(), this method may throw the rclcpp::exceptions::ParameterNotDeclaredException exception if the requested parameter has not been declared and undeclared parameters are not allowed. If the exception is thrown then none of the parameters will have been set. The callback to be called when the value for a parameter is about to be set. ", then the resulting parameter names will be like "foo..key". By default, when an instance of this class is created using one of the public constructors, it has no sub-namespace associated with it, and therefore is not a sub-node. typename MessageMemoryStrategyT::SharedPtr, The user-defined callback function to receive a message, Additional options for the creation of the. Set the given parameters, one at a time, and then return result of each set action. The queried topic_name is not remapped. Return the sub-namespace, if this is a sub-node, otherwise an empty string. If you get immediate feedback from the hardware that the change was lower than expected, call. Return the Node's internal NodeTimersInterface implementation. The message memory strategy to use for allocating messages. Return a vector of parameter types, one for each of the given names. the topic_name on which to find the subscriptions. The ParameterVarient includes ARRAY types natively, The get_value method on the variant will return the vector value. If ignore_override is true, the parameter override will be ignored. Return a list of parameters with any of the given prefixes, up to the given depth. Remove a callback registered with add_on_set_parameters_callback. Tetris.h Tetris.cpp Block.h Block.cpp Map.h Map.cppcppkey.cppros2rviz2ros2rviz2Tetrisrclcpp::Node . the node_name on which to count the publishers. If ignore_overrides is true, all the overrides of the parameters declared by the function call will be ignored. Return the number of subscribers who have created a subscription for a given topic. If the callback prevents the parameters from being set, then it will be reflected in the SetParametersResult which is returned, but no exception will be thrown. How can I build deb packages from ROS2 Bouncy Bolson packages? will be placed before each key, which would have been the case when naively expanding "namespace.key". Which return vector<T>. For instance the frame rate of a camera depends on the exposure time, the model-dependent camera dead time, the link bandwidth, etc etc. Some constraints like read_only are enforced before the callback is called. A) Is there a way to check if a parameter exists that I'm missing When the no_mangle parameter is true, the provided topic_name should be a valid topic name for the middleware (useful when combining ROS with native middleware (e.g. Right, thanks for the feedback. to your account. The official animated diagram explaining the service . Part of that is an explicit declare step for parameters, which will make "exists" make more sense. The returned smart pointer can be promoted to a shared version. Return true if a given parameter is declared. Identical to the non-templated version of this method, except that when assigning the output argument called "parameter", this method will attempt to coerce the parameter value into the type requested by the given template argument, which may fail and throw an exception. In ROS1, you could retrieve a list of parameters. Ah, I see where the disconnect is now. I did not know about the asynchronous on_parameter_event. There's get_parameters() one line above which takes a vector of names and returns a vector of ParameterVariants. Return the Node's internal NodeGraphInterface implementation. None of these commands work: Like set_parameter() this method will implicitly undeclare parameters with the type rclcpp::PARAMETER_NOT_SET. if any of the parameters have not been declared and undeclared parameters are not allowed. For example, all of these cases will work: The publisher options may optionally be passed as the third argument for any of the above cases. Basically there is no way to write a good validator. The returned namespace is a concatenation of the node namespace and the accumulated sub-namespaces, which is used as the namespace when creating entities which have relative names. You signed in with another tab or window. Create a sub-node, which will extend the namespace of all entities created with it. Node is the single point of entry for creating publishers and subscribers. rclcpp This repository contains the source code for the ROS Client Library for C++ package, included with a standard install of any ROS 2 distro. Add a new callback type for rclcpp::Node::add_on_set_parameter_callback() with the type of rcl_interfaces::msg::SetParametersResult callback(std::vector ¶meters). The returned parameter is a list of topic endpoint information, where each item will contain the node name, node namespace, topic type, endpoint type, topic endpoint's GID, and its QoS profile. And why would someone want to modify the parameters during on set parameter callback? Value to be stored in output if the parameter was not set. rcl_interfaces::msg::SetParametersResult rclcpp::Node::set_parameters_atomically. the only things that could be done during on_set_parameter_callback is rejecting an invalid parameter. arguentsurdfrobot_description, urdfjoint_state_publisher_gui, rvizurdf.rvizrvizrviz, TFRobotModelrvizlaunchrviz, ate_publisher_node) ld.add_action(rviz2_node) return ld, 1.1:1 2.VIPC, Tetris.h Tetris.cpp Block.h Block.cpp Map.h Map.cppcppkey.cpp, , The messages exchanged are used using the original messages created earlier.. Furthermore, a sub-node may be used to create additional sub-node's, in which case the sub-namespace passed to this function will further extend the sub-namespace of the existing sub-node. If undeclared parameters are allowed, see the node option rclcpp::NodeOptions::allow_undeclared_parameters, then this method will not throw an exception, and instead return a default initialized rclcpp::Parameter, which has a type of rclcpp::ParameterType::PARAMETER_NOT_SET. There is another overload which takes the std::pair with the default value and descriptor. Support pre-set and post-set parameter callbacks in addition to on-set-parameter-callback. Return the Node's internal NodeTimeSourceInterface implementation. When a callback returns a not successful result, the remaining callbacks aren't called. but what if i accidently set the parameter to be 101.0, using the current on_set_parameter_callback() behavior, then i could only reject it. remove_on_set_parameters_callback can't be used with the callbacks registered with this method. It worked, but kinda be a tricky solution and a bad habit as the parameters was implicitly stated to be constant. But i shouldn't reject it either. Also like get_parameters(), if undeclared parameters are allowed and the parameter has not been declared, then the corresponding rclcpp::Parameter will be default initialized and therefore have the type rclcpp::ParameterType::PARAMETER_NOT_SET. declare_parameter also gets the parameter. The callback may introspect other already set parameters (by calling any of the {get,list,describe}_parameter() methods), but may not modify other parameters (by calling any of the {set,declare}_parameter() methods) or modify the registered callback itself (by calling the add_on_set_parameters_callback() method). If undeclared parameters are allowed, then the default type rclcpp::ParameterType::PARAMETER_NOT_SET will be returned. if any parameter has not been declared and undeclared parameters are not allowed. Like the templated get_parameter() variant, this method will attempt to coerce the parameter values into the type requested by the given template argument, which may fail and throw an exception. And is the documentation 2years later still missing? Wouldn't it be better if i could accept it in condition that the parameter type to be casted to double value?. The name and type in the given rcl_interfaces::msg::ParameterDescriptor are ignored, and should be specified using the name argument to this function and the default value's type instead. You can see that the SetParametersResult is a boolean flag for success and an optional reason that can be used in error reporting when it fails. Note, this method cannot return a const reference, because extending the lifetime of a temporary only works recursively with member initializers, and cannot be extended to members of a class returned. Return the effective namespace that is used when creating entities. rclcpp::Node::add_on_set_parameter_callback(), https://github.com/ros/robot_state_publisher/blob/b6fbbd0a821c14d6ea34f83bcab93c77358caeef/src/robot_state_publisher.cpp#L159-L161. The text was updated successfully, but these errors were encountered: But considered the following scenario, i have a parameter that only accept the double value of 0.0 to 100.0. if i set the parameter with double value between 0.0 to 100.0, then it would be fine. In this case, how do you provide feedback that the parameter has been adjusted (e.g. Get the fully-qualified names of all available nodes. But I'm running into cases where a driver will adjust parameters that have been set, based on rules that are either too complex to reasonably encode, or are not documented at all. It should be pretty straightforward; we already have the ability to specify ranges in the parameter descriptor, we just need to enforce it when it is changed. An initial value to be used if at run-time user did not override it. I would add clipping what makes sure the parameter will be set in the rage of 0.0 to 100.0 in the setter. Callback group to execute this timer's callback in. A) Is there a way to check if a parameter exists that I'm missing B) If not, why not? @William That's what I wanted to know. If you pass multiple rclcpp::Parameter instances with the same name, then only the last one in the vector (forward iteration) will be set. If the parameter was not declared, then the output argument for this method which is called "parameter" will not be assigned a value. If the parameter has not been declared this function may throw the rclcpp::exceptions::ParameterNotDeclaredException exception, but only if the node was not created with the rclcpp::NodeOptions::allow_undeclared_parameters set to true. Maybe I can add an "exists" or "has" or "is_declared" like function at the same time. If undeclared parameters are allowed, then a default initialized descriptor will be returned for the undeclared parameter's descriptor. This will result in a parameter event indicating that the parameter was deleted. The output storage for the parameter being retrieved. if the parameter was create as read_only (immutable). Wait for a graph event to occur by waiting on an Event to become set. Currently the rclcpp::Node::add_on_set_parameter_callback() only support callback of rcl_interfaces::msg::SetParametersResult callback(const std::vector ¶meters). Return a graph event, which will be set anytime a graph change occurs. Return a map of existing service names to list of service types. This method, if successful, will result in any callback registered with add_on_set_parameters_callback to be called. This version will take a map where the value is a pair, with the default parameter value as the first item and a parameter descriptor as the second. The next bit depends on how the hardware behaves. The parameters to set in the given namespace. This allows the node developer to control which parameters may be changed. This method will result in any callback registered with add_on_set_parameters_callback to be called. Parameters can be integers, floating point numbers, booleans, string, or arrays of the previous types. This method will result in any callback registered with add_on_set_parameters_callback to be called, just one time. Construct a sub-node, which will extend the namespace of all entities created with it. This method, if successful, will result in any callback registered with add_on_set_parameters_callback to be called, once for each parameter. URDF Rviz GazeboURDF Rviz Gazebo URDFRvizURDFRvizURDFGazebo, rviz_demosrcsrc, myroboturdflaunchurdfdemo01_base.urdfdemo01_launch.py, CMakeListx.txtLaunchURDF. A relative or private topic will be expanded using this node's namespace and name. If the names vector is empty, then an empty vector will be returned. For example, if you use the prefix "foo" and the parameters "foo.ping" and "foo.pong" exist, then the returned map will have the keys "ping" and "pong". There's no reason I'm aware of that we don't have that function, probably just haven't needed it yet. For the more general case of being able to modify the parameters while in the parameter callback, what you propose would indeed work. I found below code to work, not sure if this is the recommended way, but it works. Get a clock as a non-const shared pointer which is managed by the node. The callbacks added with add_on_set_parameters_callback are stored in a different place. Multiple parameter callbacks are not possible now. Return the parameters by the given parameter names. But how would you get a param holding a vector using the 'get_parameter' syntax? Wrap rclcpp::Node with basic Lifecycle behavior? The callback signature is designed to allow handling of any of the above set_parameter* or declare_parameter* methods, and so it takes a const reference to a vector of parameters to be set, and returns an instance of rcl_interfaces::msg::SetParametersResult to indicate whether or not the parameter should be set or not, and if not why. Is there a way to get a parameter from the Parameters Server as unsigned type? read_only will be false. Set the given parameter and then return result of the set action. It is a somewhat clunky approach, but at the moment I don't have much better idea. void rclcpp::Node::remove_on_set_parameters_callback. If a callback tries to do any of the latter things, rclcpp::exceptions::ParameterModifiedInCallbackException will be thrown. See the non-templated declare_parameter() on this class for details. The output where the value of the parameter should be assigned. @clalancette i updated my feature description. The map used to store the parameter names and values, respectively, with one entry per parameter matching prefix. wouldn't it be better if i could accept it in condition that the parameter value is clamped to 100.0? Please start posting anonymously - your entry will be published after you log in or create a new account. [ROS2] What's the best way to wait for a new message? Example for changing the values on the command line: ros2 run examples_rclcpp_cbg_executor ping_pong --ros-args -p ping_period:=0.033 -p high_busyloop:=0.025. If no parameter_descriptor is given, then the default values from the message definition will be used, e.g. As for setting the range between 0 and 100.0; to me, it seems non-sensical to set a range, and then to ignore that range and clamp it. The returned reference will remain valid until the parameter is undeclared. See the simpler declare_parameters() on this class for more details. check my note, basically we could use rclcpp::Node::add_on_set_parameter_callback() to create a validator, and the hack is constant casting the parameter, and modify the value there. But if you need to use get_parameter, it looks like that isn't possible right now. Get the fully-qualified name of the node. Sign in But after that, any change to any parameter won't be taken into account. The "prefix" argument is used to list the parameters which are prefixed with that prefix, see also list_parameters(). Declare and initialize a parameter, return the effective value. Otherwise, the parameter names and values will be stored in the map and true will be returned to indicate "values" was mutated. This method will never throw the rclcpp::exceptions::ParameterNotDeclaredException exception because the action of listing the parameters is done atomically with getting the values, and therefore they are only listed if already declared and cannot be undeclared before being retrieved. the only things that could be done during on_set_parameter_callback is rejecting an invalid parameter. And lastly if you just use the return code you can integrate the fallback behavior inside your accessing logic. get_namespace() will return the original node namespace, and will not include the sub-namespace if one exists. you tried setting the frame rate to 40fps, but the driver knocked it back down to 33.7fps)? Sign up for a free GitHub account to open an issue and contact its maintainers and the community. This allows you to declare several parameters at once without a namespace. Return the Node's internal NodeLoggingInterface implementation. That is, if you want to accept any value and clamp it, then don't set a range. Get a clock as a const shared pointer which is managed by the node. What I would consider doing here is the following: I think the above should give you the behavior you want. Like get_parameters(), this method may throw the rclcpp::exceptions::ParameterNotDeclaredException exception if any of the requested parameters have not been declared and undeclared parameters are not allowed. Do you want a list of parameters in a certain namespace, like /ns/* -> ['value of /ns/foo', 'value of /ns/bar', 'value of /ns/baz'], or do you want one parameter as a vector (e.g. B) If not, why not? The rclcpp::QoS has several convenient constructors, including a conversion constructor for size_t, which mimics older API's that allows just a string and size_t to create a publisher. Return a vector of parameter descriptors, one for each of the given names. Calling remove_on_set_parameters_callback more than once with the same handler, or calling it after the shared pointer has been reset is an error. I think we have a long-term goal of being able to automatically clamp values for parameters based on the parameter description. so basically, there's no way that allows a node to modify the parameters that will be set during the on_set_parameter_callback. The default values are 0.01 seconds for all three parameters. Basically there is no way to write a good validator. If the value type of the parameter is rclcpp::PARAMETER_NOT_SET, and the existing parameter type is something else, then the parameter will be implicitly undeclared. This method will never throw the rclcpp::exceptions::ParameterNotDeclaredException exception, but will instead return false if the parameter has not be previously declared. And the bad things, we also couldn't call set_parameter() inside the callback as stated in the documentation. Like set_parameter, if any of the parameters to be set have not first been declared, and undeclared parameters are not allowed (the default), then this method will throw rclcpp::exceptions::ParameterNotDeclaredException. Here's the pull request: https://github.com/ros2/rclcpp/pull/495 , it was originally started by Shane, but I'm trying to resurrect it right now. In this ROS2 tutorial I will show you how to use an rclcpp parameter callback, so you can dynamically change parameters' values while a node is alive. There are many ways to get that information. See also: Declare and initialize several parameters with the same namespace and type. Return the list of callback groups in the node. Anyway, more information here on what you are trying to do (including a code example) would be most helpful. The documentation shows get_parameter returning an ParameterVariant but ParameterVariant doesn't seem to have an as_vector option. Return the Node's internal NodeServicesInterface implementation. Use an set_parameter_callback () to validate that the parameter is within any reasonable bounds. The fully-qualified name includes the local namespace and name of the node. Resetting or letting the smart pointer go out of scope unregisters the callback. If that callback prevents the initial value for the parameter from being set then rclcpp::exceptions::InvalidParameterValueException is thrown. The topic for this publisher to publish on. Also, besides for declaring the parameter, you're saying that it also tries to get the parameter, and if it can't find it, it will default it to std::vector({1, 2, 3})? Wrap rclcpp::Node with basic Lifecycle behavior? To get that you need to call the get_effective_namespace() method. For instance the frame rate of a camera depends on the exposure time, the model-dependent camera dead time, the link bandwidth, etc etc. Let me know if you need any help with it, and I can provide a few more pointers. if the parameter has not been declared and undeclared parameters are not allowed. privacy statement. The resulting value for each declared parameter will be returned. In ROS2, there doesn't seem to be a way to check if a parameter exists directly without attempting to get the value of the parameter. The callback functions must remain valid as long as the returned smart pointer is valid. Declare params with rclcpp Assuming argument is name of URDF file.This backwards compatibility fallback will be removed in the future. No robot_description parameter, but command-line argument available. In this case, how do you provide feedback that the parameter has been adjusted (e.g. (Fix bug that a callback not reached ()Set the minimum number of threads of the Multithreaded executor to 2 ()check thread whether joinable before join ()Set cpplint test timeout to 3 minutes ()Make sure to include-what-you-use in the node_interfaces. The callback may introspect other already set parameters (by calling any of the {get,list,describe}_parameter() methods), but may not modify other parameters (by calling any of the {set,declare}_parameter() methods) or modify the registered callback itself (by calling the add_on_set_parameters_callback() method). For note, I'm already tried to solve the problem with const casting the parameters to std::vector &. Parameter overrides are ignored by set_parameter. sw_urdf_exporterurdf packageurdflink.STLsolidworks, jointlinkURDF(), RvizRviz Could you copy the code? Get the value of a parameter by the given name, and return true if it was set. In either case, the resulting value is returned, whether or not it is based on the default value or the user provided initial value. An empty string for the prefix will match all parameters. Set the given parameters, all at one time, and then aggregate result. We may not have that API yet, but we can certainly add it or whatever the appropriate alternative is. If no parameters with the prefix are found, then the output parameter "values" will be unchanged and false will be returned. tf::createQuaternionFromYaw equivalent in ros2, Define custom messages in python package (ROS2). or what if i accidently set the parameter using an integer value of 50? [rclcpp] How do you specify Subscriber queue_size? Comments There's no reason I'm aware of that we don't have that function, probably just haven't needed it yet. 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