GR-RoseとROS2でサービス通信を行う方法について

// Copyright 2018 eSOL Co.,Ltd.
// Copyright 2018 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// 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 <Arduino.h>
#include <WiFiEsp.h>
#include <Ethernet.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>

#include "ros2_msg/Ros2String.h"

#include <uxr/client/client.h>
#include <ucdr/microcdr.h>

extern "C" {
#include <FreeRTOS.h>
#include <task.h>
}
#include <JointState.h>
// Micro-XRCE-DDS-Client key identifier of the client.
// If multiple clients connect to the same agent, each client must have a different key.
#define CLIENT_KEY      0xAAAABBC4

#define BUFFER_SIZE     UXR_CONFIG_UDP_TRANSPORT_MTU

char ssid[] = "elecom2g01-45ea1e";                 // your network SSID (name)
char pass[] = "renerene";             // your network password
int status = WL_IDLE_STATUS;          // the Wifi radio's status
byte mac[] = { 0x74, 0x90, 0x50, 0x00, 0x79, 0x03 };
IPAddress ip(192, 168, 2, 52);

uxrSession session;
uxrUDPTransport transport;
uxrUDPPlatform udp_platform;
uxrObjectId datawriter_id;
uxrStreamId output_stream;
uxrStreamId input_stream;
uint32_t count = 0;
static char agent_ip[32] = {0};

uint8_t output_best_effort_stream_buffer[BUFFER_SIZE];
uint8_t input_best_effort_stream_buffer[BUFFER_SIZE];

static bool use_ethernet = false;

void on_agent_found(const uxrAgentAddress* address, void* args);
static void prvUXRManagerTask(void * pvParameters);

void setup() {
    // Initialize the LED pin
    pinMode(PIN_LED1, OUTPUT);

    if(!use_ethernet)
    {
        // initialize serial for debugging
        Serial.begin(115200);
        // initialize serial for ESP module
        Serial6.begin(115200);
        // initialize ESP module
        WiFi.init(&Serial6);
    }
    else
    {
        // Serial output to USB
        Serial.begin(9600);
    }

    if(!use_ethernet)
    {
        // check for the presence of the shield
        if (WiFi.status() == WL_NO_SHIELD) {
            Serial.println("WiFi shield not present");
            // don't continue
            while (true);
        }
        // attempt to connect to WiFi network
        while ( status != WL_CONNECTED) {
            Serial.print("Attempting to connect to WPA SSID: ");
            Serial.println(ssid);
            // Connect to WPA/WPA2 network
            status = WiFi.begin(ssid, pass);
        }
    }
    else
    {
        // Setting IP
        Ethernet.begin(mac, ip);
    }

    // Wait for network configuration
    vTaskDelay(5000);

    // Discovery Agent
    Serial.println("Discovery Agent...");
    uxrAgentAddress chosen;
    chosen.ip = agent_ip;

    // Choose Ethernet or WiFi
    uxr_discovery_choose_ethernet(use_ethernet);

    // Try forever until Agent is found
    uxr_discovery_agents_default(INT_MAX, 1000, on_agent_found, &chosen);

    Serial.print("Chosen agent => ip: ");
    Serial.print(chosen.ip);
    Serial.print(", port: ");
    Serial.println(chosen.port);

    // Transport
    udp_platform.use_ethernet = use_ethernet;
    if (!uxr_init_udp_transport(&transport, &udp_platform, chosen.ip, chosen.port))
    {
        Serial.println("Error at create transport.");
        return;
    }

    // Session
    uxr_init_session(&session, &transport.comm, CLIENT_KEY);
    if (!uxr_create_session(&session))
    {
        Serial.println("Error at create session.");
        return;
    }

    // Streams
    output_stream = uxr_create_output_best_effort_stream(&session, output_best_effort_stream_buffer, BUFFER_SIZE);
    input_stream = uxr_create_input_best_effort_stream(&session);

    // Create entities
    uxrObjectId participant_id = uxr_object_id(0x01, UXR_PARTICIPANT_ID);
    const char* participant_xml = "<dds>"
                                      "<participant>"
                                          "<rtps>"
                                              "<name>default_xrce_participant</name>"
                                          "</rtps>"
                                      "</participant>"
                                  "</dds>";
    uint16_t participant_req = uxr_buffer_create_participant_xml(&session, output_stream, participant_id, 0, participant_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId topic_id = uxr_object_id(0x01, UXR_TOPIC_ID);
    const char* topic_xml = "<dds>"
                                "<topic>"
                                    "<name>rt/joint_states</name>"
                                    "<dataType>sensor_msgs::msg::dds_::JointState_</dataType>"
                                "</topic>"
                            "</dds>";
    uint16_t topic_req = uxr_buffer_create_topic_xml(&session, output_stream, topic_id, participant_id, topic_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId publisher_id = uxr_object_id(0x01, UXR_PUBLISHER_ID);
    const char* publisher_xml = "";
    uint16_t publisher_req = uxr_buffer_create_publisher_xml(&session, output_stream, publisher_id, participant_id, publisher_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    datawriter_id = uxr_object_id(0x01, UXR_DATAWRITER_ID);
    const char* datawriter_xml = "<dds>"
                                     "<data_writer>"
                                         "<topic>"
                                             "<kind>NO_KEY</kind>"
                                             "<name>rt/joint_states</name>"
                                             "<dataType>sensor_msgs::msg::dds_::JointState_</dataType>"
                                         "</topic>"
                                     "</data_writer>"
                                 "</dds>";
    uint16_t datawriter_req = uxr_buffer_create_datawriter_xml(&session, output_stream, datawriter_id, publisher_id, datawriter_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    xTaskCreate(prvUXRManagerTask, "TalkerDemo", configMINIMAL_STACK_SIZE * 5, NULL, 2, NULL);
}

void loop() {
    // Do nothing
    vTaskDelay(10000);
}

void on_agent_found(const uxrAgentAddress* address, void* args) {
    uxrAgentAddress* agent = (uxrAgentAddress*)args;

    Serial.print("Found agent => ip: ");
    Serial.print(address->ip);
    Serial.print(", port: ");
    Serial.println(address->port);

    memcpy((void*)(agent->ip), address->ip, 32);
    agent->port = address->port;
}

static void prvUXRManagerTask(void * pvParameters) {
    // Cannot confirm whether client is connected to agent or not.
    while (1)
    {
        // Topic serialization
    	JointState topic;
        sprintf(topic.header.frame_id , "%lu", count++);
        topic.header.stamp.nanosec = millis() * 1000000;
        topic.header.stamp.sec = millis() / 1000;
        topic.name_size = 3;
        sprintf((char*)topic.name[0], "Joint_Roll");
        sprintf((char*)topic.name[1], "Joint_Pitch");
        sprintf((char*)topic.name[2], "Joint_Yaw");
        topic.position_size = 3;
        topic.position[0] = 0.1;
        topic.position[1] = 0.2;
        topic.position[2] = 0.3;
        topic.velocity_size = 3;
        topic.velocity[0] = 0;
        topic.velocity[1] = 0;
        topic.velocity[2] = 0;
        topic.effort_size = 3;
        topic.effort[0] = 0;
        topic.effort[1] = 0;
        topic.effort[2] = 0;

        ucdrBuffer mb;
        uint32_t topic_size = JointState_size_of_topic(&topic, 0);
        uxr_prepare_output_stream(&session, output_stream, datawriter_id, &mb, topic_size);
        bool flag = JointState_serialize_topic(&mb, &topic);

        /* Set timeout period to 0s. */
        (void) uxr_run_session_time(&session, 0);
        Serial.print("Sent topic:");
        Serial.print(topic_size);
        Serial.print("\t");
        Serial.println(flag);

        // Toggle the heartbeat LED
        digitalWrite(PIN_LED1, !digitalRead(PIN_LED1));

        /* Set timeout period to 1s. */
        vTaskDelay(200);
    }

    // Delete resources
    (void) uxr_delete_session(&session);
    (void) uxr_close_udp_transport(&transport);

    // Delete this task
    vTaskDelete(NULL);
}

// Copyright 2018 eSOL Co.,Ltd.
// Copyright 2018 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// 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 <Arduino.h>
#include <WiFiEsp.h>
#include <Ethernet.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>

#include "ros2_msg/Ros2String.h"

#include <uxr/client/client.h>
#include <ucdr/microcdr.h>

extern "C" {
#include <FreeRTOS.h>
#include <task.h>
}
#include <JointState.h>

// Micro-XRCE-DDS-Client key identifier of the client.
// If multiple clients connect to the same agent, each client must have a different key.
#define CLIENT_KEY      0xCCCCDDD1

#define BUFFER_SIZE     UXR_CONFIG_UDP_TRANSPORT_MTU

char ssid[] = "elecom2g01-45ea1e";                 // your network SSID (name)
char pass[] = "renerene";             // your network password
int status = WL_IDLE_STATUS;          // the Wifi radio's status
byte mac[] = { 0x74, 0x90, 0x50, 0x00, 0x79, 0x03 };
IPAddress ip(192, 168, 2, 52);

uxrSession session;
uxrUDPTransport transport;
uxrUDPPlatform udp_platform;
uxrStreamId output_stream;
uxrStreamId input_stream;
static char agent_ip[32] = {0};

uint8_t output_best_effort_stream_buffer[BUFFER_SIZE];
uint8_t input_best_effort_stream_buffer[BUFFER_SIZE];

static bool use_ethernet = false;

void on_topic(uxrSession* session, uxrObjectId object_id, uint16_t request_id, uxrStreamId stream_id, struct ucdrBuffer* mb, void* args);
void on_agent_found(const uxrAgentAddress* address, void* args);
static void prvUXRManagerTask(void * pvParameters);

void setup() {
    // Initialize the LED pin
    pinMode(PIN_LED1, OUTPUT);

    if(!use_ethernet)
    {
        // initialize serial for debugging
        Serial.begin(115200);
        // initialize serial for ESP module
        Serial6.begin(115200);
        // initialize ESP module
        WiFi.init(&Serial6);
    }
    else
    {
        // Serial output to USB
        Serial.begin(9600);
    }

    if(!use_ethernet)
    {
        // check for the presence of the shield
        if (WiFi.status() == WL_NO_SHIELD) {
            Serial.println("WiFi shield not present");
            // don't continue
            while (true);
        }
        // attempt to connect to WiFi network
        while ( status != WL_CONNECTED) {
            Serial.print("Attempting to connect to WPA SSID: ");
            Serial.println(ssid);
            // Connect to WPA/WPA2 network
            status = WiFi.begin(ssid, pass);
        }
    }
    else
    {
        // Setting IP
        Ethernet.begin(mac, ip);
    }

    // Wait for network configuration
    vTaskDelay(5000);

    // Discovery Agent
    Serial.println("Discovery Agent...");
    uxrAgentAddress chosen;
    chosen.ip = agent_ip;

    // Choose Ethernet or WiFi
    uxr_discovery_choose_ethernet(use_ethernet);

    // Try forever until Agent is found
    uxr_discovery_agents_default(INT_MAX, 1000, on_agent_found, &chosen);

    Serial.print("Chosen agent => ip: ");
    Serial.print(chosen.ip);
    Serial.print(", port: ");
    Serial.println(chosen.port);

    // Transport
    udp_platform.use_ethernet = use_ethernet;
    if (!uxr_init_udp_transport(&transport, &udp_platform, chosen.ip, chosen.port))
    {
        Serial.println("Error at create transport.");
        return;
    }

    // Session
    uxr_init_session(&session, &transport.comm, CLIENT_KEY);
    uxr_set_topic_callback(&session, on_topic, NULL);
    if (!uxr_create_session(&session))
    {
        Serial.println("Error at create session.");
        return;
    }

    // Streams
    output_stream = uxr_create_output_best_effort_stream(&session, output_best_effort_stream_buffer, BUFFER_SIZE);
    input_stream = uxr_create_input_best_effort_stream(&session);

    // Create entities
    uxrObjectId participant_id = uxr_object_id(0x01, UXR_PARTICIPANT_ID);
    const char* participant_xml = "<dds>"
                                      "<participant>"
                                          "<rtps>"
                                              "<name>default_xrce_participant</name>"
                                          "</rtps>"
                                      "</participant>"
                                  "</dds>";
    uint16_t participant_req = uxr_buffer_create_participant_xml(&session, output_stream, participant_id, 0, participant_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId topic_id = uxr_object_id(0x01, UXR_TOPIC_ID);
    const char* topic_xml = "<dds>"
                                "<topic>"
                                    "<name>rt/joint_states</name>"
                                    "<dataType>sensor_msgs::msg::dds_::JointState_</dataType>"
                                "</topic>"
                            "</dds>";
    uint16_t topic_req = uxr_buffer_create_topic_xml(&session, output_stream, topic_id, participant_id, topic_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId subscriber_id = uxr_object_id(0x01, UXR_SUBSCRIBER_ID);
    const char* subscriber_xml = "";
    uint16_t subscriber_req = uxr_buffer_create_subscriber_xml(&session, output_stream, subscriber_id, participant_id, subscriber_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId datareader_id = uxr_object_id(0x01, UXR_DATAREADER_ID);
    const char* datareader_xml = "<dds>"
                                     "<data_reader>"
                                         "<topic>"
                                             "<kind>NO_KEY</kind>"
                                             "<name>rt/joint_states</name>"
                                             "<dataType>sensor_msgs::msg::dds_::JointState_</dataType>"
                                         "</topic>"
                                     "</data_reader>"
                                 "</dds>";
    uint16_t datareader_req = uxr_buffer_create_datareader_xml(&session, output_stream, datareader_id, subscriber_id, datareader_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    // Request topics
    uxrDeliveryControl delivery_control = {0};
    delivery_control.max_samples = UXR_MAX_SAMPLES_UNLIMITED;
    (void) uxr_buffer_request_data(&session, output_stream, datareader_id, input_stream, &delivery_control);

    xTaskCreate(prvUXRManagerTask, "ListenerDemo", configMINIMAL_STACK_SIZE * 5, NULL, 2, NULL);
}

void loop() {
    // Do nothing
    vTaskDelay(10000);
}

void on_topic(uxrSession* session, uxrObjectId object_id, uint16_t request_id, uxrStreamId stream_id, struct ucdrBuffer* mb, void* args) {
    (void) session; (void) object_id; (void) request_id; (void) stream_id;

    JointState topic;
    JointState_deserialize_topic(mb, &topic);

    Serial.println("Received topic: ");
    for(int i = 0; i < topic.position_size; i++){
        Serial.print((char*)topic.name[i]);
        Serial.print("\t");
        Serial.print(topic.position[i]);
        Serial.println();
    }

    // Toggle the heartbeat LED
    digitalWrite(PIN_LED1, !digitalRead(PIN_LED1));
}

void on_agent_found(const uxrAgentAddress* address, void* args) {
    uxrAgentAddress* agent = (uxrAgentAddress*)args;

    Serial.print("Found agent => ip: ");
    Serial.print(address->ip);
    Serial.print(", port: ");
    Serial.println(address->port);

    memcpy((void*)(agent->ip), address->ip, 32);
    agent->port = address->port;
}

static void prvUXRManagerTask(void * pvParameters) {
    // Cannot confirm whether client is connected to agent or not.
    while (1)
    {
        // Receive topics
        (void) uxr_run_session_time(&session, 1);

        vTaskDelay(1);
    }

    // Delete resources
    (void) uxr_delete_session(&session);
    (void) uxr_close_udp_transport(&transport);

    // Delete this task
    vTaskDelete(NULL);
}

// Copyright 2018 eSOL Co.,Ltd.
// Copyright 2018 Proyectos y Sistemas de Mantenimiento SL (eProsima).
//
// 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 <Arduino.h>
#include <Ethernet.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <limits.h>

#include "ros2_msg/Ros2String.h"

#include <uxr/client/client.h>
#include <ucdr/microcdr.h>

extern "C" {
#include <FreeRTOS.h>
#include <task.h>
#include "queue.h"
}
#include "aws_logging_task.h"

#include "Joy.h"

// Micro-XRCE-DDS-Client key identifier of the client.
// If multiple clients connect to the same agent, each client must have a different key.
#define CLIENT_KEY      0xCCCCDDDD

#define BUFFER_SIZE     UXR_CONFIG_TCP_TRANSPORT_MTU

byte mac[] = { 0x74, 0x90, 0x50, 0x00, 0x79, 0x03 };
IPAddress ip(192, 168, 0, 52);

uxrSession session;
uxrTCPTransport transport;
uxrTCPPlatform tcp_platform;
uxrStreamId output_stream;
uxrStreamId input_stream;

uint8_t output_best_effort_stream_buffer[BUFFER_SIZE];
uint8_t input_best_effort_stream_buffer[BUFFER_SIZE];

void on_topic(uxrSession* session, uxrObjectId object_id, uint16_t request_id, uxrStreamId stream_id, struct ucdrBuffer* mb, void* args);
bool on_agent_found(const uxrAgentAddress* address, int64_t timestamp, void* args);
static void prvUXRManagerTask(void * pvParameters);

void setup() {
    // Initialize the LED pin
    pinMode(PIN_LED1, OUTPUT);

    // Serial output to USB
    Serial.begin(9600);
    xLoggingTaskInitialize(512 * 6,	tskIDLE_PRIORITY, 15);

    Ethernet.begin(mac, ip);
	delay(100);

    // Discovery Agent
    Serial.println("Discovery Agent...");
    uxrAgentAddress chosen;

    // Try forever until Agent is found
    (void) uxr_discovery_agents_multicast(INT_MAX, 1000, on_agent_found, NULL, &chosen);

    Serial.print("Chosen agent => ip: ");
    Serial.print(chosen.ip);
    Serial.print(", port: ");
    Serial.println(chosen.port);

    // Transport
    if (!uxr_init_tcp_transport(&transport, &tcp_platform, chosen.ip, chosen.port))
    {
        Serial.println("Error at create transport.");
        return;
    }

    // Session
    uxr_init_session(&session, &transport.comm, CLIENT_KEY);
    uxr_set_topic_callback(&session, on_topic, NULL);
    if (!uxr_create_session(&session))
    {
        Serial.println("Error at create session.");
        return;
    }

    // Streams
    output_stream = uxr_create_output_best_effort_stream(&session, output_best_effort_stream_buffer, BUFFER_SIZE);
    input_stream = uxr_create_input_best_effort_stream(&session);

    // Create entities
    uxrObjectId participant_id = uxr_object_id(0x01, UXR_PARTICIPANT_ID);
    const char* participant_xml = "<dds>"
                                      "<participant>"
                                          "<rtps>"
                                              "<name>default_xrce_participant</name>"
                                          "</rtps>"
                                      "</participant>"
                                  "</dds>";
    uint16_t participant_req = uxr_buffer_create_participant_xml(&session, output_stream, participant_id, 0, participant_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId topic_id = uxr_object_id(0x01, UXR_TOPIC_ID);
    const char* topic_xml = "<dds>"
                                "<topic>"
                                    "<name>rt/joy</name>"
                                    "<dataType>sensor_msgs::msg::dds_::Joy_</dataType>"
                                "</topic>"
                            "</dds>";
    uint16_t topic_req = uxr_buffer_create_topic_xml(&session, output_stream, topic_id, participant_id, topic_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId subscriber_id = uxr_object_id(0x01, UXR_SUBSCRIBER_ID);
    const char* subscriber_xml = "";
    uint16_t subscriber_req = uxr_buffer_create_subscriber_xml(&session, output_stream, subscriber_id, participant_id, subscriber_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    uxrObjectId datareader_id = uxr_object_id(0x01, UXR_DATAREADER_ID);
    const char* datareader_xml = "<dds>"
                                     "<data_reader>"
                                         "<topic>"
                                             "<kind>NO_KEY</kind>"
                                             "<name>rt/joy</name>"
            "<dataType>sensor_msgs::msg::dds_::Joy_</dataType>"
                                         "</topic>"
                                     "</data_reader>"
                                 "</dds>";
    uint16_t datareader_req = uxr_buffer_create_datareader_xml(&session, output_stream, datareader_id, subscriber_id, datareader_xml, UXR_REPLACE);

    // In order to avoid buffer overflow, uxr_flash_output_streams() has to be
    // called everytime entities message is created.
    (void) uxr_flash_output_streams(&session);

    // Request topics
    uxrDeliveryControl delivery_control = {0};
    delivery_control.max_samples = UXR_MAX_SAMPLES_UNLIMITED;
    (void) uxr_buffer_request_data(&session, output_stream, datareader_id, input_stream, &delivery_control);

    xTaskCreate(prvUXRManagerTask, "ListenerDemo", configMINIMAL_STACK_SIZE * 5, NULL, 2, NULL);
}

void loop() {
    // Do nothing
    vTaskDelay(10000);
}

void on_topic(uxrSession* session, uxrObjectId object_id, uint16_t request_id, uxrStreamId stream_id, struct ucdrBuffer* mb, void* args) {
    (void) session; (void) object_id; (void) request_id; (void) stream_id;

    Joy topic;
    Joy_deserialize_topic(mb, &topic);

    Serial.println("Received topic: ");
    Serial.println(topic.header.frame_id);
    Serial.println(topic.header.stamp.sec);
    Serial.println(topic.header.stamp.nanosec);
    for(int i = 0; i < 8; i++){
        Serial.print(topic.axes[i]);
    	Serial.print(" ");
    }
    Serial.println();
    for(int i = 0; i < 11; i++){
        Serial.print(topic.buttons[i]);
    	Serial.print(" ");
    }
    Serial.println();

    // Toggle the heartbeat LED
    digitalWrite(PIN_LED1, !digitalRead(PIN_LED1));
}

bool on_agent_found(const uxrAgentAddress* address, int64_t timestamp, void* args) {
    (void) timestamp; (void) args;

    Serial.print("Found agent => ip: ");
    Serial.print(address->ip);
    Serial.print(", port: ");
    Serial.println(address->port);
    return true;
}

static void prvUXRManagerTask(void * pvParameters) {
    // Cannot confirm whether client is connected to agent or not.
    while (1)
    {
        // Receive topics
        (void) uxr_run_session_time(&session, 1);

        vTaskDelay(1);
    }

    // Delete resources
    (void) uxr_delete_session(&session);
    (void) uxr_close_tcp_transport(&transport);

    // Delete this task
    vTaskDelete(NULL);
}