I am using ROS Melodic in Ubuntu 16.04.
I am working with turtlebot 3 burger and trying out simulations on gazebo.
I have written a simple code to make the turtlebot move in a circle.
The code works perfectly as everything was working a couple of days ago.
Now when I try to launch it using
roslaunch assignment3_ws move.launch code:=circle
I get the following error:
ERROR: could not contact master [https://localhost:11311]
The traceback for the exception was written to the log file
I tried running it in every possible way.
With roscore, without roscore.
Even the network is setup properly in the bash file.
Can anyone provide a solution?
Have you changed the ROS_MASTER_URI environment variable to 192.168.1.162 ?
if you are using simulation and you need to set your ROS_MASTER_URI to localhost.
you only change ROS_MASTER_URI if you are trying to connect to remote ROS systems(Servers, other PCs, etc).
Related
Before explaining what my problem is, please know that I have looked up for solutions on similar topics but none of them seems to work nor even to corresponds to my problem.
What I am trying to do:
I have this python code on multiple files that I run with flask with the following command:
python -m flask run --host=0.0.0.0
So far, everything works, but I would like this code to automatically run everytime the computer boots. In the future this will be used on mini PCs without any graphical interface nor human intervention.
Since I need to do some configuration checks before running the web server, I've created a powershell script that ends with Flask running (using the previous command).
So far, everything works too. Now we're coming to the problem:
I'd like this script to run when I boot the machine. Specificity: Every things needs to work with Administrator privileges, on the local system without any interaction.
I've tried scheduled tasks but Flask won't run even if the rest of the script works (like creating folders or other things)
Ok, it's not a big deal I have other ways to do it, so I've created a Windows Service in C# to run the Script at startup on the local system.
The script works, I've checked the privileges too, everything's fine but arriving at the flask command line that is supposed to make it run, nothing works.
It's the same thing if I run flask using "pythonw" which is supposed to run python as a background process.
What the problem seems to be:
Well, as long as I run flask and I have either a command prompt or a powershell terminal, everything works greats. But if in a way or another I run the script as a background process, it won't work.
Normally it would take around 30 seconds for Flask to start-up. Here if I try to create a folder right after flask ended starting up (as a test) I can see the folder is created almost instantly, which means the process is immediately killed.
The problem doesn't seem to come from the service itself but really Windows that kills the process I don't know why
I'm running out of idea so if you guys have anything that I could try it would really help me.
I'm currently running Robotframework in Eclipse on Windows 10 OS. I'm using an external python library that allows students and teachers to use this extracted library to connect to our hardware devices. I'm automating the extractions from the main site package made by our developers. If more than one device is plugged into the USB ports on the PC, then the code does the following:
x = input("Select one device:")
selected = int(x)
This causes a terminal prompt so the user has to type in a 0, or 1 for example, then hit the ENTER key. User response will allow the code to further process a connect to the selected device. Note, this prompt is not a GUI. So when I run Robotframework, it will execute the steps up to the point where it's prompting.
It seems like this should be pretty easy, but I can't seem to figure it out. Since you're inside a piece of code that's waiting for input, how do you make RobotFramework do something with it?
Edit: It occurs to me that maybe there's a way to execute a delayed Robotframework step that starts an external python command after a specified time, to throw a '0' and a RETURN key response. I had a python file made from an import of pynput.py library which appears to work from the command line execution (prints a 0, or a 1, and a return line feed). There's gotta be an easier way I'd think, but I don't know what it is.
Edit: Can I run a keyword from a listener that watches for the command prompt and the keyword runs another python file to feed the prompt? If I get this to work, then all I have to do is leave the devices on the USB port (or hub for that matter), and select the devices I want to do further testing on. Our devices are supported Blooth tooth as well but I need to run both USB and BLE tests to verify our Python extractions the teachers and students can use.
Edit: The other option is to use a software programmable hub and select the USB with a specific device on it, but I'm trying to avoid that.
OK, I solved it using Robotframework background process. I wrote a small python file that gets executed from the process. It has a 5 second timer (more than I need) and then Robotframework runs the next Test Case step. The Python file then does some keyboard presses, selecting the port and an ENTER key which goes out to the console (feeding the input prompt). It connects the sensor.
So in my Robotframework Test Case I do the following:
*** Test Case ***
smoke_test
Start process . Python . usbportselect
open usb
The Python program called from the process looks like this:
import time
import pynput
from pynput.keyboard import Key, Controller
keyboard = Controller()
def choose_usb(portvalue)
keyboard.press(portvalue)
keyboard.release(portvalue)
keyboard.press(Key.enter)
keyboard.release(Key.enter)
time.sleep(5)
choose_usb('0')
Note: I'm pretty sure this won't fix all the problems with using processes, but it's at least a start and a way to feed input to a prompt resulted from a future Test Case step
I'm trying to run a swift based web server using Kitura on Ubuntu.
This is following command to start hello word server.
.build/debug/helloworld
I can launch standalone process using .build/debug/helloworld &
but launching with that creates multiple process if execute again.
Or I've to kill old process then start new If I want to run only single process.
I've followed following tutorial to get server up running. But don't want to use Bluemix to deploy application. Instead I want to launch it on AWS ubuntu.
http://www.kitura.io/en/starter/gettingstarted.html
I assume there must be more easy and proper way to do this.
As you can see I'm almost newbie for servers.
You have to kill the Kitura process in order to stop a Kitura Server app - there is no other way to stop it.
If you just want to test your server you can run it inside a screen session. Screen is an essential utility for managing remote servers via ssh.
If you want to run it properly as a service/daemon you should look into systemd.
I'm setting up some new VNC servers. I already have this setup working with CentOS 6.3, although I'm not certain that this difference is the real problem.
One of the window managers I'm making available is fluxbox, but when I start it, I always get the following: Error: Couldn't connect to XServer. Here's my setup:
fluxbox: fluxbox-1.1.1-5.el6.x86_64
vnc : tigervnc-server-1.1.0-5.el6_4.1.x86_64
OS : CentOS 6.4
Note that I can start other window managers: Gnome, KDE, openbox, xfce4, etc.
I gutted my ~/.vnc/xstartup script so it only loads an xterm. Then, I tried running startfluxbox &, but still got the error. Obviously, VNC is working, since my xterm opened up OK. I can start firefox, another xterm or other app requiring X, and even fluxbox comes up, but it is worthless in its current state, since it is not connected to the X session.
What is fluxbox looking for? Are there some log files I can look at to give me some clues?
Thanks,
David
CentOS/RHEL 6.4 and up have upgraded libX11 and Xorg.
The $DISPLAY var handling has changed in libX11.
This one in particular is described in this git commit:
http://cgit.freedesktop.org/xorg/lib/libX11/commit/?id=f92e754297ec5fdb81068b56a4435026666224fa
we run our fluxbox with this script in our vnc configs now:
/usr/bin/fluxbox -display "$DISPLAY.0"
OK, I think I've figured out the problem, so I'm answering my own question.
In VNC, I usually specify a display number. (Note, however, that the problem occurs even if vncserver uses the first available display number.) So, I start the vncserver as:
vncserver :17
This should create an X session where my $DISPLAY is set to :17.0, but in CentOS 6.4, the $DISPLAY is set to :17 instead. Apparently, unlike other window managers, fluxbox is unable to handle this inaccuracy. The problem, then, was that fluxbox was trying to connect to :17 and was unable to do so.
My solution, as suggested by someone answering a different problem, was to set $DISPLAY as part of the invocation of fluxbox. So, in my ~/.vnc/xstartup file, I have:
DISPLAY=$DISPLAY.0 startfluxbox &
Note that this may not work for other releases of CentOS, so you might wish to test the release of the box you are using before adding the DISPLAY=... setting to the command.
I am trying to make a 'dual core' RaspberryPi for a project I am working on. I had followed this tutorial by Simon Cox. Unfortunately I could not get the two RasPi to talk to each other. (This was using Hydra as the process manager)
After looking more carefully at the MPICH installers guide, which can be found here, I tried to use the -phrase to pass the passphrase I had created. However I could not find it as part of the hydra commands. So I re-installed with smpd and after many compiling attempts. I configured with:
/configure -prefix=/home/pi/mpich-install --with-pm=smpd --with-pmi=smpd
I also had to install libbsl-dev to get the MD5 that smpd requires. I also exported the path that the commands mpiexec and mpicc are in. After setting the passphrase I copied the image to a second SD card and put it in a second RasPi. I then set up the passphrase using ssh-keygen.
I was able to run the cpi program on the master Pi and the slave Pi individually but when I tried to run multiple processes on both at the same time I got the error
Fatal error in MPI_Init: Other MPI error, error stack:
MPIR_Init``_thread(392).................:
MPID_Init(139)........................: channel initialization failed
MPIDI_CH3_Init(38)....................:
MPID_nem_init(196)....................:
MPIDI_CH3I_Seg_commit(366)............:
MPIU_SHMW_Hnd_deserialize(324)........:
MPIU_SHMW_Seg_open(863)...............:
MPIU_SHMW_Seg_create_attach_templ(637): open failed - No such file or directory
Can someone please suggest how I can either fix this problem or get the RaspberryPis to communicate using MPICH?
Thanks
E.Lee
If anyone else has this problem make sure your hosts don't have the same name!
You can change it by following this tutorial http://raspi.tv/2012/how-to-change-the-name-of-your-raspberry-pi-new-hostname