Micropython variable sharing

gistfile1.txt

#
# This version works, notice where ros_event_callbasck is declasred
#

from microros import readROSMsg, publishMsg, registerEventSubscription, init_event_queue
import machine
import utime
import _thread
import gc

print("\r\nInit Event Queue")
init_event_queue()

#
# Thread code 
#
def ros_event_thread():

#
# THis works
#
    def ros_event_callback(data):
        print("Ros did something")
        #print(data)
    
    print("\r\nRegistgering Event Subscription")
    registerEventSubscription("CmdVel", "Twist", ros_event_callback)
    
    while True:
        print("In event Thread")
        utime.sleep(2)
        readROSMsg()
        
# Function that initializ
_thread.start_new_thread(ros_event_thread, ())

while True:

    print("In Main Thread")
    
    utime.sleep(2)
    
#
# This does not work, notice that where the ros_event_callback is declared, it is
# crated on the MP main THread but we are trying to access in the event thread. 
#
from microros import readROSMsg, publishMsg, registerEventSubscription, init_event_queue
import machine
import utime
import _thread
import gc

print("\r\nInit Event Queue")
init_event_queue()

####
def ros_event_callback(data):
    print("Ros did something")
    #print(data)
####        
def ros_event_thread():
    print("\r\nRegistgering Event Subscription")
    registerEventSubscription("CmdVel", "Twist", ros_event_callback)
    
    while True:
        print("In event Thread")
        utime.sleep(2)
        readROSMsg()
        
# Function that initializ
_thread.start_new_thread(ros_event_thread, ())

while True:
    print("In Main Thread")
    utime.sleep(2)
    
    

#
# Shows how call back is registered in the C Module
#
mp_obj_t g_eventName = NULL;
mp_obj_t g_eventType = NULL;
mp_obj_t g_eventCallback = NULL;

mp_obj_t registerEventSubscription(mp_obj_t eventName, mp_obj_t eventType, mp_obj_t eventCallback) {
    g_eventName = eventName;
    g_eventType = eventType; 
    g_eventCallback = eventCallback;

    return eventName;
}


# 
# Poll the Queue for a new event. Note: the queue is configured to transfer an
# unsigned long, the ROS event payload informatuon is not being conveyed yet.
# A Timer task wiil load unsigned longs into the queue and when received will
# call a callback dispatch method, this method will run on the Event thread and
not the MP main thread. 

mp_obj_t readROSMsg() {

    const TickType_t xDelay = 100 / portTICK_PERIOD_MS;
    unsigned long value;

    if (xQueueReceive(mp_uros_queue, &value, 0 )== pdTRUE) {
        if (g_eventCallback != NULL) {
            mp_call_function_1(g_eventCallback, NULL);
        }
    }
   

    return NULL;
}