sas_datalogger

Log data through ROS2 into a .mat-compliant file.

Main goodies

Node

Call with ros2 run sas_datalogger <NODE_NAME>.

Node name	Description
sas_datalogger_node.py	The main node that will store the data received through specialised topics.
#include <sas_datalogger/sas_datalogger_client.hpp>	The DataloggerClient that must be used for cpp binaries.
from sas_datalogger import DataloggerClient	The DataloggerClient that must be used in Python scripts.

Example

cd docker
docker compose up

CPP Usage

Refer to the example src/examples/sas_datalogger_client_example.cpp.

sas_datalogger/src/examples/sas_datalogger_client_example.cpp

Lines 25 to 102 in c18667d

	#include <rclcpp/rclcpp.hpp>
	#include <sas_common/sas_common.hpp>
	#include <sas_datalogger/sas_datalogger_client.hpp>
	/*********************************************
	* SIGNAL HANDLER
	* *******************************************/
	#include<signal.h>
	static std::atomic_bool kill_this_process(false);
	void sig_int_handler(int)
	{
	kill_this_process = true;
	}
	int main(int argc,char** argv)
	{
	if(signal(SIGINT, sig_int_handler) == SIG_ERR)
	{
	throw std::runtime_error("::Error setting the signal int handler.");
	}
	rclcpp::init(argc,argv,rclcpp::InitOptions(),rclcpp::SignalHandlerOptions::None);
	auto node = std::make_shared<rclcpp::Node>("sas_datalogger_client_example");
	try
	{
	sas::DataloggerClient datalogger_client(node); //If you're storing more than 100 values at each loop, this might need adjustment
	RCLCPP_WARN_STREAM_ONCE(node->get_logger(), "*******RUN THIS EXAMPLE WITH THE LAUNCH FILE, NOT THE BINARY DIRECTLY.*******");
	RCLCPP_WARN_STREAM_ONCE(node->get_logger(), "Run with 'ros2 launch sas_datalogger sas_datalogger_client_example_launch.py'");
	RCLCPP_WARN_STREAM_ONCE(node->get_logger(), "*****************************************************************************");
	RCLCPP_INFO_STREAM_ONCE(node->get_logger(), "Waiting for a connection with sas_datalogger...");
	while( (not datalogger_client.is_enabled()) and (not kill_this_process))
	{
	std::this_thread::sleep_for(std::chrono::microseconds(100));
	rclcpp::spin_some(node);
	}
	RCLCPP_INFO_STREAM_ONCE(node->get_logger(), "Connected to sas_datalogger.");
	RCLCPP_INFO_STREAM_ONCE(node->get_logger(), "Logging started...");
	RCLCPP_INFO_STREAM_ONCE(node->get_logger(), "Logging each value 5 times...");
	for (auto i = 0; i < 5; i++)
	{
	MatrixXd A(3,4); A << 1,2,3,4,5,6,7,8,9,10,11,12;
	datalogger_client.log("A",A);
	VectorXd v(5); v << 1,5,10,15,20;
	datalogger_client.log("v",v);
	std::vector<double> std_v = {2,4,6,8,10};
	datalogger_client.log("std_v",std_v);
	datalogger_client.log("value_double",5);
	datalogger_client.log("value_string","Hello world!");
	}
	RCLCPP_INFO_STREAM_ONCE(node->get_logger(), "Logging ended. Close the `sas_datalogger_node` and check the resulting .mat file.");
	while(not kill_this_process)
	{
	std::this_thread::sleep_for(std::chrono::microseconds(100));
	rclcpp::spin_some(node);
	}
	}
	catch (const std::exception& e)
	{
	RCLCPP_ERROR_STREAM_ONCE(node->get_logger(), std::string("::Exception::") + e.what());
	}
	sas::display_signal_handler_none_bug_info(node);
	return 0;
	}

Python Usage

Refer to the example scripts/sas_datalogger_client_example_py.py.

sas_datalogger/scripts/sas_datalogger_client_example_py.py

Lines 27 to 82 in c18667d

	import numpy as np
	from sas_datalogger import DataloggerClient
	from sas_core import Clock
	from sas_common import rclcpp_init, rclcpp_Node, rclcpp_spin_some, rclcpp_shutdown
	def main(args=None):
	"""
	An example showing some of the functionalites of the DataloggerClient.
	:param args: Not used directly by the user, but used by ROS2 to configure
	certain aspects of the Node.
	"""
	try:
	rclcpp_init() # Init rclcpp to use the sas python bindings. They do not use rclpy.
	# However, you can also have rclpy nodes active as long as you manage their spin
	# correctly.
	rclcpp_node = rclcpp_Node("sas_datalogger_client_example_py")
	datalogger_client = DataloggerClient(rclcpp_node)
	clock = Clock(0.001)
	clock.init()
	while not datalogger_client.is_enabled():
	rclcpp_spin_some(rclcpp_node)
	clock.update_and_sleep()
	for i in range(0, 5):
	A = np.array([[1, 2, 3],
	[4, 5, 6],
	[7, 8, 9],
	[10, 11, 12]])
	datalogger_client.log("A", A)
	v = np.array([1, 5, 10, 15, 20])
	datalogger_client.log("v", v)
	datalogger_client.log("value_double", 5)
	datalogger_client.log("value_string", "Hello world!")
	clock.init()
	while True:
	rclcpp_spin_some(rclcpp_node)
	clock.update_and_sleep()
	rclcpp_shutdown() # Shutdown rclcpp
	except KeyboardInterrupt:
	print("Interrupted by user")
	if __name__ == '__main__':
	main()