I am using a USB microwave source, which communicates via a virtual COM port.
Communication is done via python. Everything works fine, as long as I am executing the code blockingly.
However, as soon as any communication is done in a thread
I get a SerialException: Attempting to use a port that is not open. Is there an obvious reason, why this is happening? Nothing else, at least originating from my software, is trying to communicate with the port during that time.
The highest level script:
from serial import SerialException
import deer
import windfreak_usb
try:
deer.mw_targets = windfreak_usb.WindfreakSynthesizer()
except SerialException:
deer.mw_targets.port.close()
deer.mw_targets = windfreak_usb.WindfreakSynthesizer()
deer_mes = deer.DeerMeasurement(f_start=0.9e9,
f_end=1.2e9,
df=3e6,
f_nv=1.704e9,
seq=["[(['mw'],28),([],tau),(['mw', 'mwy'],56),([],tau),(['mw'],28),([],100)]",
"[(['mw'],28),([],tau),(['mw', 'mwy'],56),([],tau),(['mw'],84),([],100)]"],
power_nv=10,
power_targets=3,
tau=700
)
deer_mes.run(10e6) # <- this works perfectly, as it is the blocking version
# deer_mes.start(10e6) # <- raises the SerialException at the line indicated below
deer.mw_targets.port.close()
A reduced form of the microwave source (windfreak_usb.py):
import serial
import synthesizer
class WindfreakSynthesizer(synthesizer.Synthesizer):
def __init__(self):
synthesizer.Synthesizer.__init__(self)
self.port = serial.Serial(
port='COM14',
baudrate=9600,
timeout=10
)
self.off()
def __del__(self):
self.port.close()
def off(self):
self.port.write('o0')
def power(self, p):
p = int(p)
self.port.write('a{}'.format(p))
A reduced form of the measurement class (deer.py):
import threading
import time
import numpy
import os
from PyQt4 import QtCore
from PyQt4.QtCore import QObject
import matplotlib.pyplot as plt
import hardware
import matpickle
import pulsed
import pulser
import savepath
import synthesizer
if 'pg' not in globals():
pg = pulser.Pulser()
if 'mw_targets' not in globals():
mw_targets = synthesizer.Synthesizer()
timeout = 30
CurrentMeasurement = None # global variable pointing to the currently active measurement
class DeerMeasurement(QObject):
update = QtCore.pyqtSignal()
def __init__(self, f_start, f_end, df, f_nv, seq, power_nv, power_targets, tau, sweeps_per_iteration=50e3,
switching_time=300e-6):
super(QObject, self).__init__()
""" setting all parameters as self.parameter """
self.power_targets = power_targets
self.fs = numpy.arange(f_start, f_end + df, df)
self.abort = threading.Event()
self.save_deer()
def run(self, sweeps):
global CurrentMeasurement
if CurrentMeasurement is not None:
print('Deer Warning: cannot start measurement while another one is already running. Returning...')
return
CurrentMeasurement = self
# Start measurement
print('Deer measurement started.')
mw_targets.power(self.power_targets) # <- This causes the SerialException.
""" Here comes the actual measurement, that is never executed, as the line above kills the thread already with the SerialException. """
def start(self, sweeps, monitor=None):
"""Start Measurement in a thread."""
if monitor is not None:
monitor.register(self)
if not hasattr(self, 'mes_thread'):
# noinspection PyAttributeOutsideInit
self.mes_thread = threading.Thread(target=self.run, args=(sweeps,))
self.mes_thread.start()
else:
print('Already threading')
Any help is highly appreciated, as running the measurement outside a thread is not an option.
Best regards!
Related
Im trying to implement multi threading (parallel processing) with python and using mutex threading. I have first process that check the Pressure Value and the modem update(in the code implemented with odom_callback and callback_modem functions), and second process that calls ROS SERVICES ( in the code implemented with ros_serice_server server and imu_client client functions). Here is the implementation code in python
#!/usr/bin/env python3
from __future__ import print_function
import rospy
import numpy as np
from os import system
import time
import threading
import Microcontroller_Manager_Serial as Serial
import IMU_Functions as IMU
import Motors_Functions as Motor
import Pressure_Functions as Pressure
from geometry_msgs.msg import Vector3
import Modem_Functions as Modem
import threading
import time
import serial
import serial.tools.list_ports
from time import sleep
from std_msgs.msg import Float32
from std_msgs.msg import String
from demo_teleop.srv import ImuValue,ImuValueResponse
P0 = 1.01325 #Default Pressure
mutex = threading.Lock()
Communication_Mode_ = 0
pub_pressure = rospy.Publisher('depth',Vector3,queue_size=1)
pub_modem = rospy.Publisher('modem_data',Float32,queue_size=1)
def handle_ros_services(req):
mutex.acquire(blocking=True)
print("Server Read Data:")
global T0
data_received = Pressure.Pressure_Get_Final_Values(1,1)
#print("Server Read Data:")
T0 = (np.int16((data_received[6]<<24) | (data_received[7]<<16) | (data_received[8]<<8) | (data_received[9])))/10000
T=T0
temperature = T
current_x_orientation_s = temperature
print("Returning Service Temperature Data", current_x_orientation_s)
return ImuValueResponse(current_x_orientation_s, True)
mutex.release()
def ros_serice_server():
s = rospy.Service('imu_value', ImuValue, handle_ros_services)
print("Ready to get_value")
def odom_callback():
# reentrang processing
mutex.acquire(blocking=True)
# work serial port here, e.g. send msg to serial port
global P0
data_received = Pressure.Pressure_Get_Final_Values(1,1)
#P1 = (np.int16((data_received_pressure[6]<<24) | (data_received_pressure[7]<<16) | (data_received_pressure[8]<<8) | (data_received_pressure[9])))/10000
P1 = (np.int16((data_received[6]<<24) | (data_received[7]<<16) | (data_received[8]<<8) | (data_received[9])))/10000
#P0 = (np.int16((data_received_pressure[6]<<24) | (data_received_pressure[7]<<16) | (data_received_pressure[8]<<8) | (data_received_pressure[9])))/10000
P0 = (np.int16((data_received[6]<<24) | (data_received[7]<<16) | (data_received[8]<<8) | (data_received[9])))/10000
P = P0 # Relative Measured Pressure
feedback =Vector3()
feedback.x = 0 #Angular Velocity
feedback.y = 0
feedback.z = P/9.81 #Depth
pressure = feedback.z
print("Pressure : ", pressure)
pub_pressure.publish(feedback)
# reentrant processing
mutex.release()
def callback_modem(event):
# reentrant processing
mutex.acquire(blocking=True)
# work serial port here, e.g. check for incoming data
event = Serial.Serial_Port_Receive_Data(20,0.2)
if (event == 1): # Received data from acoustic modem
modem_data= event
pub_modem.publish(modem_data)
print("received ")
else:
print("not received...... ")
mutex.release()
if __name__ == '__main__':
# initialize serial port here
Serial.Serial_Port_Standard()
rospy.init_node('imu_value')
ros_serice_server()
rospy.Timer(rospy.Duration(1), callback_modem)
while not rospy.is_shutdown():
try:
odom_callback()
except:
print('pass')
And the client node
#!/usr/bin/env python3
from __future__ import print_function
import rospy
import sys
import numpy as np
from os import system
import threading
import Microcontroller_Manager_Serial as Serial
import IMU_Functions as IMU
import Motors_Functions as Motor
import Pressure_Functions as Pressure
from geometry_msgs.msg import Vector3
import Modem_Functions as Modem
import time
import serial
import serial.tools.list_ports
from time import sleep
from std_msgs.msg import Float32
from std_msgs.msg import String
from demo_teleop.srv import *
mutex = threading.Lock()
Communication_Mode_ = 0
pub_modem = rospy.Publisher('modem_data',Float32,queue_size=1)
def imu_client():
mutex.acquire(blocking=True)
rospy.wait_for_service('imu_value')
imu_value = rospy.ServiceProxy('imu_value', ImuValue)
print("Request call send")
resp1 = imu_value(0.05)
return resp1.current_x_orientation_s
mutex.release()
if __name__ == "__main__":
rospy.init_node('client_node_f')
while not rospy.is_shutdown():
try:
print("entering client")
value = imu_client()
print(value)
time.sleep(1)
except:
print('pass')
So the output is following. The output of the first process with the ROS Services Server is
Pressure : 0.10602446483180428
Server Read Data:
Returning Service Temperature Data 1.0401
And then after calling the client I got
entering client
Request call send
1.0401
entering client
The problem is that after calling the ROS SERVICE client node the process stop so doesn't continue with the first process (Pressure value and modem update) . The ROS SERVICES process should be call only on demand and should HALT the first process (Pressure and modem) and then is should resume with the work. So, do I need to implement SEMAPHORES for the ROS SERVICES call ? If yes how it should be in the code. So I do need kind of synchronization , right?Please any help?
Your problem is:
def handle_ros_services(req):
mutex.acquire(blocking=True)
...
return ImuValueResponse(current_x_orientation_s, True)
mutex.release()
Because of the return statement, the release is never executed.
You need at the end:
value = ImValueResponse(...)
mutex.release()
return value
Even better would be to use your mutex as part of a with statement:
with mutex:
do anything you want, knowing that the lock will be released
at the end, even if you return or throw an exception.
I'm using a Gstreamer to storyboard some video. I put each frame in multiprocessing.Manager().Namespace() for transfer between processes. In this case, a memory leak is observed. During 10 hours of application work, memory consumption increased by 400 MB. If you comment out the call of self.update_frame(buf.extract_dup(0, buf.get_size())), then the memory leak does not occur.
An example of a memory leak test:
import unittest
import gi
import traceback
import os, psutil
from multiprocessing import Process, Manager, Event
gi.require_version('Gst', '1.0')
from gi.repository import Gst
class RtpNamespaceTest(unittest.TestCase):
pipeline_str = '''
videotestsrc pattern=ball ! \
appsink name=handle-app-sink \
emit-signals=True \
max-buffers=1 \
drop=True \
'''
name_space = Manager().Namespace()
pipeline = None
event_interrupt: Event = Event()
def start(self):
# initializing gstreamer, subscribing to rtp-stream
Gst.init(None)
print(self.pipeline_str)
self.pipeline = Gst.parse_launch(self.pipeline_str)
self.pipeline.set_state(Gst.State.PLAYING)
self.appsink = self.pipeline.get_by_name('handle-app-sink')
self.appsink.connect("new-sample", self.on_new_buffer)
bus = self.pipeline.get_bus()
# listen to messages until storyboarding is stopped
while not self.event_interrupt.is_set():
bus.timed_pop_filtered(10000, Gst.MessageType.ANY)
# stops the pipeline, free up resources
self.pipeline.set_state(Gst.State.NULL)
def on_new_buffer(self, src):
sample = src.emit("pull-sample")
buf = sample.get_buffer()
# writing a frame in binary format in Namespace()
self.update_frame(buf.extract_dup(0, buf.get_size()))
print(f"RAM = {psutil.Process(os.getpid()).memory_info().rss / 1024 / 1024}")
return Gst.FlowReturn.OK
def update_frame(self, frame: bytes):
self.name_space.frame = frame
def test_repository(self):
while True:
try:
self.start()
except Exception as ex:
traceback.print_exc()
time.sleep(float(10))
Let's say we have a concurrent SMACH container sm_con which includes two state machines SM1 and SM2. I need to find a way for SM1 to continuously update some data and for SM2 to access (and eventually also modify) the same data. I thought about solving this by passing the userdata of sm_con to SM1 and SM2 as input- and output-keys hoping that if SM1 modifies the data it would automatically overwrite sm_cons userdata (kind of like working with pointers in c++) but this doesn't work.
The corresponding code would look like this:
import smach
import smach_ros
import rospy
class st1(smach.State):
def __init__(self, outcomes=['successful', 'preempted']):
smach.State.__init__(self, outcomes, input_keys=['in_test'], output_keys=['out_test'])
def execute(self, userdata):
if self.preempt_requested():
self.service_preempt()
return 'preempted'
rospy.logerr('test 1: '+str(userdata.in_test))
userdata.out_test=userdata.in_test+1
return 'successful'
class st2(smach.State):
def __init__(self, outcomes=['successful', 'preempted']):
smach.State.__init__(self, outcomes, input_keys=['in_test'])
def execute(self, userdata):
#time.sleep(2)
if self.preempt_requested():
self.service_preempt()
return 'preempted'
rospy.logerr('test 2: ' + str(userdata.in_test))
return 'successful'
if __name__=="__main__":
rospy.init_node('test_state_machine')
sm_con = smach.Concurrence(outcomes=['success'],
default_outcome='success'
)
sm_con.userdata.testdata = 0
with sm_con:
sm_1 = smach.StateMachine(outcomes=['success', 'preempted'], input_keys=['testdata'], output_keys=['testdata'])
with sm_1:
smach.StateMachine.add('ST1', st1(),
remapping={'in_test': 'testdata', 'out_test': 'testdata'},
transitions={'successful': 'ST1'})
sm_2 = smach.StateMachine(outcomes=['success', 'preempted'], input_keys=['testdata'])
with sm_2:
smach.StateMachine.add('ST2', st2(),
remapping={'in_test':'testdata'},
transitions={'successful': 'ST2'})
smach.Concurrence.add('SM1', sm_1)
smach.Concurrence.add('SM2', sm_2)
# Execute SMACH plan
outcome = sm_con.execute()
print('exit-outcome:' + outcome)
# Wait for ctrl-c to stop the application
rospy.spin()
Running this code, the output 'test 1: ...' shows that inside SM1 the userdata gets incremented while the output 'test 2: ...' shows that SM2 doesn't access the incremented data as the output remains 0.
How can I modify some data in SM1 and access the modified data in SM2?
I found a workaround for this using mutable objects like described here.
Applied on the code above, it would look like the following:
import smach
import smach_ros
import rospy
class st1(smach.State):
def __init__(self, outcomes=['successful', 'preempted']):
smach.State.__init__(self, outcomes, input_keys=['in_test'])
def execute(self, userdata):
if self.preempt_requested():
self.service_preempt()
return 'preempted'
rospy.logerr('test 1: '+str(userdata.in_test))
userdata.in_test[0]=userdata.in_test[0]+1
return 'successful'
class st2(smach.State):
def __init__(self, outcomes=['successful', 'preempted']):
smach.State.__init__(self, outcomes, input_keys=['in_test'])
def execute(self, userdata):
#time.sleep(2)
if self.preempt_requested():
self.service_preempt()
return 'preempted'
rospy.logerr('test 2: ' + str(userdata.in_test[0]))
return 'successful'
if __name__=="__main__":
rospy.init_node('test_state_machine')
sm_con = smach.Concurrence(outcomes=['success'],
default_outcome='success'
)
sm_con.userdata.testdata = [0]
with sm_con:
sm_1 = smach.StateMachine(outcomes=['success', 'preempted'], input_keys=['testdata'])
with sm_1:
smach.StateMachine.add('ST1', st1(),
remapping={'in_test': 'testdata'},
transitions={'successful': 'ST1'})
sm_2 = smach.StateMachine(outcomes=['success', 'preempted'], input_keys=['testdata'])
with sm_2:
smach.StateMachine.add('ST2', st2(),
remapping={'in_test':'testdata'},
transitions={'successful': 'ST2'})
smach.Concurrence.add('SM1', sm_1)
smach.Concurrence.add('SM2', sm_2)
# Execute SMACH plan
outcome = sm_con.execute()
print('exit-outcome:' + outcome)
# Wait for ctrl-c to stop the application
rospy.spin()
Since this is only a workaround, refer to my corresponding issue-post here for more information.
import gi
gi.require_version('Gst', '1.0')
from gi.repository import GObject #,Gtk
from gi.repository import Gst as gst
import datetime
def take_photo():
GObject.threads_init()
gst.init(None)
pipeline = gst.Pipeline()
video_source = gst.ElementFactory.make('v4l2src', 'video_source')
vconvert = gst.ElementFactory.make('videoconvert', 'vconvert')
clock = gst.ElementFactory.make('clockoverlay', 'clock')
timer= gst.ElementFactory.make('timeoverlay','timer')
vrate = gst.ElementFactory.make('videorate', 'vrate')
sconvert = gst.ElementFactory.make('videoconvert', 'sconvert')
png = gst.ElementFactory.make('pngenc', 'png')
multi_sink = gst.ElementFactory.make('multifilesink', 'multi_sink')
caps = gst.caps_from_string("video/x-raw,format=RGB,width=800,height=600,framerate=5/1")
timer.set_property('valignment','bottom')
timer.set_property('halignment','right')
clock.set_property('time-format','%Y/%m/%d %H:%M:%S')
clock.set_property('valignment','bottom')
caps1 = gst.caps_from_string("video/x-raw,framerate=1/1")
png.set_property('snapshot',True)
multi_sink.set_property('location','/home/pi/frame%05d.png')
filter = gst.ElementFactory.make("capsfilter", "filter")
filter.set_property("caps", caps)
filter1 = gst.ElementFactory.make("capsfilter", "filter1")
filter1.set_property("caps", caps1)
pipeline.add(video_source)
pipeline.add(vconvert)
pipeline.add(timer)
pipeline.add(clock)
pipeline.add(filter)
pipeline.add(vrate)
pipeline.add(filter1)
pipeline.add(sconvert)
pipeline.add(png)
pipeline.add(multi_sink)
video_source.link(filter)
filter.link(vconvert)
vconvert.link(timer)
timer.link(clock)
clock.link(vrate)
vrate.link(filter1)
filter1.link(sconvert)
sconvert.link(png)
png.link(multi_sink)
bus = pipeline.get_bus()
pipeline.set_state(gst.State.PLAYING)
print "Capture started"
bus = pipeline.get_bus()#class
msg = bus.timed_pop_filtered(gst.CLOCK_TIME_NONE,gst.MessageType.ERROR | gst.MessageType.EOS)
print msg
pipeline.set_state(gst.State.NULL)
Once the program run for the first time, it capture the image and when i run the second time, nothing happen. And i need to restart the whole python program in order to it to run again. Anybody can help me solve it?
What about implementing it as class, so do a proper initializationof gstreamer stuff.. and in take_photo you just play the pipe and stop it afterwards.. in should be reusable then (from gstreamer point of view.. pipe can go to NULL and PLAYING over and over):
class TakePhoto:
def __init__(self):
GObject.threads_init()
gst.init(None)
self.pipeline = gst.Pipeline()
.. do the element creation and their linking etc ..
def take_photo(self): #this is reusable
bus = self.pipeline.get_bus()
self.pipeline.set_state(gst.State.PLAYING)
print "Capture started"
bus = self.pipeline.get_bus()#class
msg = bus.timed_pop_filtered(gst.CLOCK_TIME_NONE,gst.MessageType.ERROR | gst.MessageType.EOS)
print msg
self.pipeline.set_state(gst.State.NULL)
Then python shell you can initialize one instance and call take_photo multiple times:
TakePhoto tp
tp.take_photo()
tp.take_photo()
This code is typed out of my head so I take no responsibility if it boils your HDD or anything.. and also I am not used to code in python.. so it may be full of bugs :D
but HTH
I've got a program that will eventually receive data from an external source over serial, but I'm trying to develop the display-side first.
I've got this "main" module that has the simulated data send and receive. It updates a global that is used by a Matplotlib stripchart. All of this works.
#-------------------------------------------------------------------------------
# Name: BBQData
# Purpose: Gets the data from the Arduino, and runs the threads.
#-------------------------------------------------------------------------------
import time
import math
import random
from threading import Thread
import my_globals as bbq
import sys
import BBQStripChart as sc
import serial
import BBQControl as control
ser = serial.serial_for_url('loop://', timeout=10)
def simData():
newTime = time.time()
if not hasattr(simData, "lastUpdate"):
simData.lastUpdate = newTime # it doesn't exist yet, so initialize it
simData.firstTime = newTime # it doesn't exist yet, so initialize it
if newTime > simData.lastUpdate:
simData.lastUpdate = newTime
return (140 + 0.05*(simData.lastUpdate - simData.firstTime), \
145 + 0.022*(simData.lastUpdate - simData.firstTime), \
210 + random.randrange(-10, 10))
else:
return None
def serialDataPump():
testCtr = 0;
while not bbq.closing and testCtr<100:
newData = simData()
if newData != None:
reportStr = "D " + "".join(['{:3.0f} ' for x in newData]) + '\n'
reportStr = reportStr.format(*newData)
ser.write(bytes(reportStr, 'ascii'))
testCtr+=1
time.sleep(1)
bbq.closing = True
def serialDataRcv():
while not bbq.closing:
line = ser.readline()
rcvdTime = time.time()
temps = str(line, 'ascii').split(" ")
temps = temps[1:-1]
for j, x in enumerate(temps):
bbq.temps[j].append(float(x))
bbq.plotTimes.append(rcvdTime)
def main():
sendThread = Thread(target = serialDataPump)
receiveThread = Thread(target = serialDataRcv)
sendThread.start()
receiveThread.start()
# sc.runUI()
control.runControl() #blocks until user closes window
bbq.closing = True
time.sleep(2)
exit()
if __name__ == '__main__':
main()
## testSerMain()
However, I'd like to add a SEPARATE tkinter window that just has the most recent data on it, a close button, etc. I can get that window to come up, and show data initially, but none of the other threads run. (and nothing works when I try to run the window and the plot at the same time.)
#-------------------------------------------------------------------------------
# Name: BBQ Display/Control
# Purpose: displays current temp data, and control options
#-------------------------------------------------------------------------------
import tkinter as tk
import tkinter.font
import my_globals as bbq
import threading
fontSize = 78
class BBQControl(tk.Tk):
def __init__(self,parent):
tk.Tk.__init__(self,parent)
self.parent = parent
self.labelFont = tkinter.font.Font(family='Helvetica', size=int(fontSize*0.8))
self.dataFont = tkinter.font.Font(family='Helvetica', size=fontSize, weight = 'bold')
self.makeWindow()
def makeWindow(self):
self.grid()
btnClose = tk.Button(self,text=u"Close")
btnClose.grid(column=1,row=5)
lblFood = tk.Label(self,anchor=tk.CENTER, text="Food Temps", \
font = self.labelFont)
lblFood.grid(column=0,row=0)
lblPit = tk.Label(self,anchor=tk.CENTER, text="Pit Temps", \
font = self.labelFont)
lblPit.grid(column=1,row=0)
self.food1Temp = tk.StringVar()
lblFoodTemp1 = tk.Label(self,anchor=tk.E, \
textvariable=self.food1Temp, font = self.dataFont)
lblFoodTemp1.grid(column=0,row=1)
#spawn thread to update temps
updateThread = threading.Thread(target = self.updateLoop)
updateThread.start()
def updateLoop(self):
self.food1Temp.set(str(bbq.temps[1][-1]))
def runControl():
app = BBQControl(None)
app.title('BBQ Display')
app.after(0, app.updateLoop)
app.mainloop()
bbq.closing = True
if __name__ == '__main__':
runControl()
Your title sums up the problem nicely: Tkinter doesn't play well with threads. That's not a question, that's the answer.
You can only access tkinter widgets from the same thread that created the widgets. If you want to use threads, you'll need your non-gui threads to put data on a queue and have the gui thread poll the queue periodically.
One way of getting tkinter to play well with threads is to modify the library so all method calls run on a single thread. Two other questions deal with this same problem: Updating a TKinter GUI from a multiprocessing calculation and Python GUI is not responding while thread is executing. In turn, the given answers point to several modules that help to solve the problem you are facing. Whenever I work with tkinter, I always use the safetkinter module in case threads appear to be helpful in the program.