ros2 rclcpp parameter

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. so basically, there's no way that allows a node to modify the parameters that will be set during the on_set_parameter_callback. Sorry I thought you wanted to list multiple parameters. This method will result in any callback registered with add_on_set_parameters_callback to be called. The resulting list of parameter names are used to get the values of the parameters. 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. [rclcpp] How do you specify Subscriber queue_size? 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. In all cases, the parameter is never set or declared within the node. 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. If a callback tries to do any of the latter things, rclcpp::exceptions::ParameterModifiedInCallbackException will be thrown. There's get_parameters() one line above which takes a vector of names and returns a vector of ParameterVariants. It looks like the documentation is not complete. ( 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 The syntax has been getting easier over time. Return a map of existing topic names to list of topic types. Resetting or letting the smart pointer go out of scope unregisters the callback. 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})? If undeclared parameters are allowed, then the parameter is implicitly declared with the default parameter meta data before being set. 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. 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. Return the sub-namespace, if this is a sub-node, otherwise an empty string. 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). Already on GitHub? This method, if successful, will result in any callback registered with add_on_set_parameters_callback to be called. The updated values can include unsetting the value. And why would someone want to modify the parameters during on set parameter callback? I did not know about the asynchronous on_parameter_event. rclcpp: ROS Client Library for C++ rclcpp provides the canonical C++ API for interacting with ROS. Can you explain more? rcl_interfaces::msg::SetParametersResult result; Encapsulation of Quality of Service settings. 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. Return the number of subscribers who have created a subscription for a given topic. The name of the parameter to check for being declared. 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. Wrap rclcpp::Node with basic Lifecycle behavior? The name expansion is naive, so if you set the namespace to be "foo. Get value of parameter using rclcpp::ParameterType as template argument. There are two different things here: My suggestion for now is to implement the first one. If the parameter was declared, and therefore has a value, then it is assigned into the "parameter" argument of this method. this->get_parameter("foo", foo); syntax? If no parameters with the prefix are found, then the output parameter "values" will be unchanged and false will be returned. Return a graph event, which will be set anytime a graph change occurs. The queried topic_name is not remapped. I think we have a long-term goal of being able to automatically clamp values for parameters based on the parameter description. @clalancette thanks, works for me! I found below code to work, not sure if this is the recommended way, but it works. 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. Wrap rclcpp::Node with basic Lifecycle behavior? Right, thanks for the feedback. Return the NodeOptions used when creating this node. 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. If the parameter was not declared, then the output argument for this method which is called "parameter" will not be assigned a 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. See get_sub_namespace() and get_effective_namespace() for examples. Resetting or letting the smart pointer go out of scope after calling remove_on_set_parameters_callback is not a problem. Create a new node with the specified name. 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. Return the Node's internal NodeClockInterface implementation. 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. const rcl_interfaces::msg::ParameterDescriptor &. The callback to be called when the value for a parameter is about to be set. Value to be stored in output if the parameter was not set. 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). 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. If a callback tries to do any of the latter things, rclcpp::exceptions::ParameterModifiedInCallbackException will be thrown. 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. If undeclared parameters are allowed, then a default initialized descriptor will be returned. Return the Node's internal NodeWaitablesInterface implementation. 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. if the parameter has not been declared and undeclared parameters are not allowed. Return a vector of parameter types, one for each of the given names. If ignore_overrides is true, all the overrides of the parameters declared by the function call will be ignored. not a sub-node. Yes, that is the default. That is, if you want to accept any value and clamp it, then don't set a range. 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. 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. And is the documentation 2years later still missing? template, template, template, template. That means that we'd have to change the signature of the parameter callbacks again. Anyway, more information here on what you are trying to do (including a code example) would be most helpful. 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. The resulting value for each declared parameter will be returned. 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). This may be done by using this method, create_sub_node(). if the allocation of the OnSetParametersCallbackHandle fails. Return the Node's internal NodeTopicsInterface implementation. Returns current time from the time source specified by clock_type. See the simpler declare_parameters() on this class for more details. The output where the value of the parameter should be assigned. Const casting the parameter is obviously not a permanent solution. Yes that's exactly what i means, as described by @clalancette. Get the fully-qualified names of all available nodes. Node is the single point of entry for creating publishers and subscribers. I'm sorry, I haven't reached this thread for a while. to your account. 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. This method will never throw the rclcpp::exceptions::ParameterNotDeclaredException exception, but will instead return false if the parameter has not be previously declared. Set the given parameters, one at a time, and then return result of each set action. 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. Behaves like set_parameter, except that it sets multiple parameters, failing all if just one of the parameters are unsuccessfully set. Declare and initialize a parameter, return the effective value. The map contains default values for parameters. Or is 'foo' of the rclcpp::Parameter type? 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. None of these commands work: privacy statement. Like set_parameter() this method will implicitly undeclare parameters with the type rclcpp::PARAMETER_NOT_SET. By clicking Sign up for GitHub, you agree to our terms of service and This allows you to declare several parameters at once without a namespace. The message memory strategy to use for allocating messages. 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. Register a callback to be called anytime a parameter is about to be changed. 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 fully-qualified name includes the local namespace and name of the node. 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. Construct a sub-node, which will extend the namespace of all entities created with it. 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. More Node is the single point of entry for creating publishers and subscribers. A) Is there a way to check if a parameter exists that I'm missing B) If not, why not? The documentation shows get_parameter returning an ParameterVariant but ParameterVariant doesn't seem to have an as_vector option. Set the given parameters, all at one time, and then aggregate result. See also: Declare and initialize several parameters with the same namespace and type. RvizQt, 11, gazebo Like the version of get_parameter() which returns a bool, this method will not throw the rclcpp::exceptions::ParameterNotDeclaredException exception. If that callback prevents the initial value for the parameter from being set then rclcpp::exceptions::InvalidParameterValueException is thrown. The default values are 0.01 seconds for all three parameters. using rclcpp::Node::OnParametersSetCallbackType = rclcpp::node_interfaces::NodeParametersInterface::OnParametersSetCallbackType Constructor & Destructor Documentation Node () [1/3] Create a new node with the specified name. In this case, how do you provide feedback that the parameter has been adjusted (e.g. const char* rclcpp::Node::get_fully_qualified_name, rclcpp::CallbackGroup::SharedPtr rclcpp::Node::create_callback_group. 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? 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. the namespace of the node associated with the name. There is another overload which takes the std::pair with the default value and descriptor. 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 callback functions must remain valid as long as the returned smart pointer is valid. if the requested type does not match the value of the parameter which is stored. The "prefix" argument is used to list the parameters which are prefixed with that prefix, see also list_parameters(). See the non-templated declare_parameter() on this class for details. ", then the resulting parameter names will be like "foo..key". Depending on your use case each different one has tradeoffs. Could you copy the code? 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. rclcpp::Node::add_on_set_parameter_callback(), https://github.com/ros/robot_state_publisher/blob/b6fbbd0a821c14d6ea34f83bcab93c77358caeef/src/robot_state_publisher.cpp#L159-L161. 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. That way you wouldn't even have to write a parameter callback to accomplish this. typename MessageMemoryStrategyT::SharedPtr, The user-defined callback function to receive a message, Additional options for the creation of the. void rclcpp::Node::remove_on_set_parameters_callback. 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. It worked, but kinda be a tricky solution and a bad habit as the parameters was implicitly stated to be constant. 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. This will result in a parameter event indicating that the parameter was deleted. Using a validator before updating the parameters is all nice and well if validation can be done beforehand. 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). Which return vector<T>. Sign in the only things that could be done during on_set_parameter_callback is rejecting an invalid parameter. Either all of the parameters are set or none of them are set. [rclcpp] How do you specify Subscriber queue_size? 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). 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. If you pass multiple rclcpp::Parameter instances with the same name, then only the last one in the vector (forward iteration) will be set. I would add clipping what makes sure the parameter will be set in the rage of 0.0 to 100.0 in the setter. or what if i accidently set the parameter using an integer value of 50? Given a list of parameter names, it will request an update of the values subject to validation of the values. You just use a std::clamp as you set the value in the callback. And lastly if you just use the return code you can integrate the fallback behavior inside your accessing logic. Or in this example how come that the parameter doesn't need to be declared? For the more general case of being able to modify the parameters while in the parameter callback, what you propose would indeed work. You signed in with another tab or window. 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. Note: in this particular case the driver SDK immediately returns the adjusted value which simplifies the logic. 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. Part of that is an explicit declare step for parameters, which will make "exists" make more sense. Set the given parameter and then return result of the set action. What I would consider doing here is the following: I think the above should give you the behavior you want. Use get_effective_namespace() to get the full namespace used by entities. Return the Node's internal NodeLoggingInterface implementation. Basically there is no way to write a good validator. 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. This allows the node developer to control which parameters may be changed. 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. The callbacks added with add_on_set_parameters_callback are stored in a different place. URDF Rviz GazeboURDF Rviz Gazebo URDFRvizURDFRvizURDFGazebo, rviz_demosrcsrc, myroboturdflaunchurdfdemo01_base.urdfdemo01_launch.py, CMakeListx.txtLaunchURDF. The topic for this publisher to publish on. rcl_interfaces::msg::ParameterDescriptor rclcpp::Node::describe_parameter, if the number of described parameters is more than one. Maybe I can add an "exists" or "has" or "is_declared" like function at the same time. If you get immediate feedback from the hardware that the change was lower than expected, call. Return the Node's internal NodeTimersInterface implementation. 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. If you're going to be checking more than one parameter, the listing is likely valuable. 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. (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. Parameter overrides are ignored by set_parameter. In ROS1, you could retrieve a list of parameters. If undeclared parameters are allowed, then the default type rclcpp::ParameterType::PARAMETER_NOT_SET will be returned. [ROS2] What's the best way to wait for a new message? Declare and initialize a parameter with a type. I have another case of a driver for an experimental camera that is even more complex. If the exception is thrown then none of the parameters will have been set. An empty string for the prefix will match all parameters. For removing it, use set_on_parameters_set_callback(nullptr). For each key in the map, a parameter with a name of "namespace.key" will be set to the value in the map. Return the number of publishers that are advertised on a given topic. Return the topic endpoint information about publishers on a given topic. The node from which a new sub-node is created. will be placed before each key, which would have been the case when naively expanding "namespace.key". starts with a leading '/'. That means that we'd have to change the signature of the parameter callbacks again. Get the fully-qualified name of the node. Run the simplest ros2 (C++) program (and fail) Inspecting the simplest ROS (C++) program Distributed Logging with rosconsole Play Around Conclusion Installing ROS2 (if it hasn't already been installed) For Ubuntu Linux, you can follow these instructions, and for other platforms, see the main ros2 installation instructions. Return the effective namespace that is used when creating entities. foo is std::vector. 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. [1.0, 1.0, 0.0])? The output storage for the parameter being retrieved. Return the Node's internal NodeParametersInterface implementation. get_namespace() will return the original node namespace, and will not include the sub-namespace if one exists. Note also that the fully qualified node name is unaffected by a sub-namespace. Add a callback for when parameters are being set. 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. Get the parameter values for all parameters that have a given prefix. Currently the rclcpp::Node::add_on_set_parameter_callback() only support callback of rcl_interfaces::msg::SetParametersResult callback(const std::vector ¶meters). To avoid this, use the declare_parameter() method which returns an rclcpp::ParameterValue instead. Create a sub-node, which will extend the namespace of all entities created with it. There's no reason I'm aware of that we don't have that function, probably just haven't needed it yet. Get a clock as a const shared pointer which is managed by the node. Let me know if you need any help with it, and I can provide a few more pointers. 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. 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. Please start posting anonymously - your entry will be published after you log in or create a new account. If ignore_override is true, the parameter override will be ignored. if the sub-namespace is absolute, i.e. The order of the callback is the reverse from the registration order. If that callback prevents the initial value for any parameter from being set then rclcpp::exceptions::InvalidParameterValueException is thrown. Return the parameters by the given parameter names. There are many ways to get that information. For instance the frame rate of a camera depends on the exposure time, the model-dependent camera dead time, the link bandwidth, etc etc. However, if the namespace is an empty string, then no leading '.' the node_name on which to count the publishers. Get the value of a parameter by the given name, and return true if it was set. When I've used this in the past, I've always had a separate member variable internal to the class that I set. Even a std::clamp inside the on_set_parameter_callback won't work as the parameter itself is immutable. 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. 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. If the names vector is empty, then an empty vector will be returned. remove_on_set_parameters_callback can also be used. tf::createQuaternionFromYaw equivalent in ros2, Define custom messages in python package (ROS2). I don't think anyone is currently working on this, so help here would be appreciated. This method will result in any callback registered with add_on_set_parameters_callback to be called, once for each parameter. The messages exchanged are used using the original messages created earlier.. A) Is there a way to check if a parameter exists that I'm missing We may not have that API yet, but we can certainly add it or whatever the appropriate alternative is. The name of the parameter to be undeclared. 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. We don't have it in the demos but there are tests covering it you can use as an example, here. topic_name may be a relative, private, or fully qualified topic name. Parameters can be integers, floating point numbers, booleans, string, or arrays of the previous types. But i shouldn't reject it either. 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. It should be possible to register it before or after the parameters are declared. Assuming argument is name of URDF file.This backwards compatibility fallback will be removed in the future. 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. 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. Using a validator before updating the parameters is all nice and well if validation can be done beforehand. Remove a callback registered with add_on_set_parameters_callback. Parameters Exceptions InvalidNamespaceError if the namespace is invalid Node () [2/3] Return the Node's internal NodeTimeSourceInterface implementation. the topic_name on which to find the subscriptions. Is there a way to get a parameter from the Parameters Server as unsigned type? Return a vector of parameter descriptors, one for each of the given names. remove_on_set_parameters_callback can't be used with the callbacks registered with this method. Declare params with rclcpp The names of the parameters to be retrieved. Some constraints like read_only are enforced before the callback is called. rcl_interfaces::msg::ListParametersResult rclcpp::Node::list_parameters. you tried setting the frame rate to 40fps, but the driver knocked it back down to 33.7fps)? if the parameter was create as read_only (immutable). Get a clock as a non-const shared pointer which is managed by the node. If no parameter_descriptor is given, then the default values from the message definition will be used, e.g. 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. The latter, one parameter name, which is why I figured get_parameters wouldn't work. 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); A relative or private topic will be expanded using this node's namespace and 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. Parameters are set in the order they are given within the input vector. 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(). But if you need to use get_parameter, it looks like that isn't possible right now. With the current callback, it is entirely possible to clamp a value as you set it. The official animated diagram explaining the service . Support pre-set and post-set parameter callbacks in addition to on-set-parameter-callback. Here is a simple way to declare and get a vector of integers in Galactic: This shows how to declare the parameter. if any parameter has not been declared and undeclared parameters are not allowed. wouldn't it be better if i could accept it in condition that the parameter value is clamped to 100.0? Delete a handler returned by add_on_set_parameters_callback. Wouldn't it be better if i could accept it in condition that the parameter type to be casted to double value?. Please start posting anonymously - your entry will be published after you log in or create a new account. if it starts with a leading '/'. sw_urdf_exporterurdf packageurdflink.STLsolidworks, jointlinkURDF(), RvizRviz the topic_name on which to find the publishers. if any of the parameters have not been declared and undeclared parameters are not allowed. The sub-namespace should be relative, and an exception will be thrown if the sub-namespace is absolute, i.e. Return the parameter descriptor for the given parameter name. Tetris.h Tetris.cpp Block.h Block.cpp Map.h Map.cppcppkey.cppros2rviz2ros2rviz2Tetrisrclcpp::Node . Additional options to control creation of the node. Ah, I see where the disconnect is now. Wait for a graph event to occur by waiting on an Event to become set. 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. Return a list of parameters with any of the given prefixes, up to the given depth. DDS) apps). The map used to store the parameter names and values, respectively, with one entry per parameter matching prefix. Set Parameters. as_bool () bool rclcpp::Parameter::as_bool ( ) const as_int () int64_t rclcpp::Parameter::as_int ( ) const wouldn't it be better if i could accept it in condition that the parameter value is clamped to 100.0? Get the parameter value, or the "alternative_value" if not set, and assign it to "parameter". 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. 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. https://github.com/ros2/rclcpp/blob/r Ah, so when you do 'auto foo', is 'foo' of the std::vector type? get_value () [2/2] template<typename T > decltype (auto) rclcpp::Parameter::get_value ( ) const inline Get value of parameter using c++ types as template argument. Return the list of callback groups in the node. 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. But how would you get a param holding a vector using the 'get_parameter' syntax? @William That's what I wanted to know. The names which are used as keys in the values map have the prefix removed. For note, I'm already tried to solve the problem with const casting the parameters to std::vector &. If the parameter was not set, then the "parameter" argument is assigned the "alternative_value". 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. I am also working on some improvements right now so that you can have read-only parameters. GitHub What is set_on_parameters_set_callback doing? We didn't provide the specific API to check if a parameter exists. An initial value to be used if at run-time user did not override it. Return a map of existing service names to list of service types. With parameters you can already change the configuration of the node at runtime. 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? An optional, custom description for the parameter. 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. Support for pre-set and post-set parameter callback. If the parameter has not been declared, then this method may throw the rclcpp::exceptions::ParameterNotDeclaredException exception. Well occasionally send you account related emails. The ParameterVarient includes ARRAY types natively, The get_value method on the variant will return the vector value. I have another case of a driver for an experimental camera that is even more complex. Return the Node's internal NodeGraphInterface implementation. joint_state_publisher_guirobot_state_publisher: joint_state_publisher_guijoint_state_publisherjoint_state_publisher_guiURDF , robot_state_publisher, robot_descriptionparameters. Set one or more parameters, one at a time. declare_parameter also gets the parameter. 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. 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. The returned reference will remain valid until the parameter is undeclared. When a callback returns a not successful result, the remaining callbacks aren't called. We also support arrays of primatives. For the slightly different case than what @tfoote linked to, here's how to get a single parameter as an array of values. the only things that could be done during on_set_parameter_callback is rejecting an invalid parameter. 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. 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. Undeclare a previously declared parameter. 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