I'm running a chatbot on Ubuntu server on Amazon EC2 instance. I want to be able to run the python3 program even after closing the pUTTY window. So far I've tried 'Ctrl+a, d' as well as 'Ctrl+z, bg'. However both methods did not seem to work after closing the pUTTY window. I referenced the following youtube video:
Would really appreciate any help!
I hope the question is "how to keep the python script running even after closing the putty"
IMO, you can use 2 approaches here.
Use nohup
The unix command nohup can make your program run in background even after exiting the terminal.
You can run it like
nohup python3 LP_poolVol.py > /dev/null &
nohup will make the script running and the & at the end will make it in
background
Make the script a service
Run the script as a linux service which you can start and stop using the systemctl
You can create a service descriptor file pool-vol.service with contents similar to below.
[Unit]
Description=Pool Vol Service
After=multi-user.target
[Service]
Type=simple
Restart=always
ExecStart=/usr/bin/python3 <path-to>/LP_poolVol.py
[Install]
WantedBy=multi-user.target
Then copy this service file to /etc/systemd/system/. And then install it via the commands below
sudo systemctl daemon-reload
sudo systemctl enable pool-vol.service
sudo systemctl start pool-vol
Now your app is running as a service. You can stop or restart it using the systemctl itself like
sudo systemctl start pool-vol
Related
I am working on an RFID-based access control system for which I have a working python script. For some specific details if they matter, the main processing is done on a pi zero w, which is connected by USB to a microcontroller that handles the input from the RFID module and sends it to the pi in string format for simplicity. The pi then compares the string received to a yaml file and a schedule and uses GPIO to switch on or off a door strike using a power supply. The issue I'm running into is that the script stops running after about 30 minutes, and I'm not quite sure why, but I think the ideal solution in any case is to daemonize it, because a cron job is too subject to failure and a daemon seems very appropriate for this use. Does anyone have any suggestions for daemonizing the script such that it will start on boot and restart itself if it detects a failure or that it is no longer running?
As larsks said, you can create systemd service
sudo nano /etc/systemd/system/yourscript.service
This file should be something like this (read the documentation for more information):
[Unit]
Description=My cool script
After=multi-user.target
[Service]
User=root
WorkingDirectory=/path/to/your/script/directory/
Restart=on-failure
RestartSec=5s
ExecStart=/usr/bin/python3 your_script.py
StandardOutput=append:/var/log/your_script.log
StandardError=append:/var/log/your_script.log
SyslogIdentifier=coolawesomescript
[Install]
WantedBy=multi-user.target
Then enable and start it:
foo#bar:~$ sudo systemctl enable yourscript
foo#bar:~$ sudo systemctl start yourscript
Now your script will automatically restart when it crashes
You can check if your script actually works by typing sudo systemctl status yourscript
I have set up Flask on my Rapsberry Pi and I am using it for the sole purpose of acting as a server for an xml file which I created with a Python script to pass data to an iPad app (iRule).
My RPI is set up as headless and my access is with Windows 10 using PuTTY, WinSCP and TightVNC Viewer.
I run the server by opening a terminal window and the following command:
sudo python app1c.py
This sets up the server and I can access my xml file quite well. However, when I turn off the Windows machine and the PuTTY session, the Flask server shuts down!
How can I set it up so that the Flask server continues even when the Windows machine is turned off?
I read in the Flask documentation:
While lightweight and easy to use, Flask’s built-in server is not suitable for production as it doesn’t scale well and by default serves only one request at a time.
Then they go on to give examples of how to deploy your Flask application to a WSGI server! Is this necessary given the simple application I am dealing with?
Use:
$ sudo nohup python app1c.py > log.txt 2>&1 &
nohup allows to run command/process or shell script that can continue running in the background after you log out from a shell.
> log.txt: it forword the output to this file.
2>&1: move all the stderr to stdout.
The final & allows you to run a command/process in background on the current shell.
Install Node package forever at here https://www.npmjs.com/package/forever
Then use
forever start -c python your_script.py
to start your script in the background. Later you can use
forever stop your_script.py
to stop the script
You have multiple options:
Easy: deattach the process with &, for example:
$ sudo python app1c.py &
Medium: install tmux with apt-get install tmux
launch tmux and start your app as before and detach with CTRL+B.
Complexer:
Read run your flask script with a wsgi server - uwsgi, gunicorn, nginx.
Been stressing lately so I decide to go deep.
pm2 start app.py --interpreter python3
Use PM2 for things like this. I also use it for NodeJs app and a Python app on a single server.
Use:
$sudo python app1c.py >> log.txt 2>&1 &
">> log.txt" pushes all your stdout inside the log.txt file (You may check the application logs in it)
"2>&1" pushes all the stderr inside the log.txt file (This would push all the error logs inside log.txt)
"&" at the end makes it run in the background.
You would get the process id immediately after executing this command with which you can monitor or verify it.
$sudo ps -ef | grep <process-id>
Hope it helps..!!
You can always use nohup to run any scripts as background process.
nohup python script.py
This will run your script in background and also have its logs appended in nohup.out file which will be located in the directory script.py is store.
Make sure, you close the terminal and not press Ctrl + C. This will allow it to run in background even when you log out.
To stop it from running , ssh in to the pi again and run ps -ef |grep nohup and kill -9 XXXXX
where XXXX is the pid you will get ps command.
I've always found a detached screen process to be best for use cases such as these.
Run:
screen -m -d sudo python app1c.py
I was trying to run my flask app for testing in my GitHub CI and the step where I was running the app was getting stuck for ever. The reason was that it was never releasing the command line
Best solution I found was a combination of two other responses in here:
nohup python script.py &
I am working on raspberry pi 3 about 3 months , I had a problem when I started working with it.
I couldn't find an efficient and safe way to run a python script on raspberry when it turns on(without monitor and mouse and keyboard).At the moment I have added "$sudo run myscript.py &" at /etc/profile but sometimes when I turn it on my script doesn't run until I connect monitor and mouse and keyboard to it and run the script with GUI and after that it works fine (again without mouse and keyboard).
I want to know is there any solution that I will be sure my script will run after I turn raspberry pi on?
Thanks a lot
You will want to setup a service and user sudo service <my_service> [start, stop, restart] to get it working on startup. See here for reference.
The /etc/profile is executed when new shell session in being started, so unless you start at least single shell session your script will not be run. Moreover it will be terminated when session stops, and if you start multiple sessions then the script will also be started for each session, which is probably not what you want.
Depending on your init system you would need to create SysVinit or systemd service. Assuming you use systemd based distro (which is currently default for most Linux distributions) you need to do following:
Step 1: Place your script in location from which it will be executed by service. For example /usr/local/bin/ may be good choice.
Step 2: Create service file. Assuming you want to name it myscript.service, create file at following path /etc/systemd/system/myscript.service with following content:
[Unit]
Description=myscript
[Service]
ExecStart="/usr/bin/python /usr/local/bin/myscript.py"
[Install]
WantedBy=multi-user.target
Step 3: Reload systemd daemon and enable your service:
systemctl daemon-reload
systemctl enable myscript
Now after you restart your system, your service should be automatically started. You can verify that using command systemctl status myscript, which returns service status.
I'm using a Raspberry Pi 3 with Raspbian distribution.
I've written a script in Python 3 and I would need to start it up automatically just when system boots up, without logging in.
I would recommend using systemd to achieve this. Take for example your python script is called hello.py.
Create a systemd service file at /lib/systemd/system/hello.service:
[Unit]
Description=hello.py service file
After=multi-user.target
[Service]
Type=simple
ExecStart=/usr/bin/python /dir/to/your/hello.py
Restart=always
[Install]
WantedBy=multi-user.target
The full list of commands and functions for the systemd service file can be found here.
Add appropriate permissions to the .service file: sudo chmod 644 /lib/systemd/system/hello.service
Reload the systemd daemon: sudo systemctl daemon-reload
Enable the hello systemd service: sudo systemctl enable hello.service
You can check that your service is running by using the command: sudo systemctl status hello.service and check for any errors using sudo journalctl
Raspberry PI has quite good support. Tasks can be schedualed with usage of "crontab" command.
You can find documentation on: Documentation
Within this documentation you have example for running "python" script on Raspberry Pi reboot.
Hope it helps!
I have set up Flask on my Rapsberry Pi and I am using it for the sole purpose of acting as a server for an xml file which I created with a Python script to pass data to an iPad app (iRule).
My RPI is set up as headless and my access is with Windows 10 using PuTTY, WinSCP and TightVNC Viewer.
I run the server by opening a terminal window and the following command:
sudo python app1c.py
This sets up the server and I can access my xml file quite well. However, when I turn off the Windows machine and the PuTTY session, the Flask server shuts down!
How can I set it up so that the Flask server continues even when the Windows machine is turned off?
I read in the Flask documentation:
While lightweight and easy to use, Flask’s built-in server is not suitable for production as it doesn’t scale well and by default serves only one request at a time.
Then they go on to give examples of how to deploy your Flask application to a WSGI server! Is this necessary given the simple application I am dealing with?
Use:
$ sudo nohup python app1c.py > log.txt 2>&1 &
nohup allows to run command/process or shell script that can continue running in the background after you log out from a shell.
> log.txt: it forword the output to this file.
2>&1: move all the stderr to stdout.
The final & allows you to run a command/process in background on the current shell.
Install Node package forever at here https://www.npmjs.com/package/forever
Then use
forever start -c python your_script.py
to start your script in the background. Later you can use
forever stop your_script.py
to stop the script
You have multiple options:
Easy: deattach the process with &, for example:
$ sudo python app1c.py &
Medium: install tmux with apt-get install tmux
launch tmux and start your app as before and detach with CTRL+B.
Complexer:
Read run your flask script with a wsgi server - uwsgi, gunicorn, nginx.
Been stressing lately so I decide to go deep.
pm2 start app.py --interpreter python3
Use PM2 for things like this. I also use it for NodeJs app and a Python app on a single server.
Use:
$sudo python app1c.py >> log.txt 2>&1 &
">> log.txt" pushes all your stdout inside the log.txt file (You may check the application logs in it)
"2>&1" pushes all the stderr inside the log.txt file (This would push all the error logs inside log.txt)
"&" at the end makes it run in the background.
You would get the process id immediately after executing this command with which you can monitor or verify it.
$sudo ps -ef | grep <process-id>
Hope it helps..!!
You can always use nohup to run any scripts as background process.
nohup python script.py
This will run your script in background and also have its logs appended in nohup.out file which will be located in the directory script.py is store.
Make sure, you close the terminal and not press Ctrl + C. This will allow it to run in background even when you log out.
To stop it from running , ssh in to the pi again and run ps -ef |grep nohup and kill -9 XXXXX
where XXXX is the pid you will get ps command.
I've always found a detached screen process to be best for use cases such as these.
Run:
screen -m -d sudo python app1c.py
I was trying to run my flask app for testing in my GitHub CI and the step where I was running the app was getting stuck for ever. The reason was that it was never releasing the command line
Best solution I found was a combination of two other responses in here:
nohup python script.py &