I'm trying to run a script on windows 10 machine that I set a server in my LAN.
I would like for the script to restart 30 seconds after it finished, forever.
Is there any better way then putting it in an infinite while loop?
Here is my code:
import Time
while True:
print("Here does all the things it's supposed to")
# Does something
time.wait(30)
While this works, I'm worried that it will affect performance and maybe memory of of the server or slowing it down in time.
Is there any better way to run a code forever in a loop in windows, perhaps with some command for terminal or any other option better then mine?
Kindly note the machine is a windows 10, 64 Bit arch, not a linux machine.
You can look up a term more famously known as a "chron job"
Heres an article I found out which can help: https://www.technipages.com/scheduled-task-windows
using "chron" you can schedule when to run a script at exact date and time. Or choose how to run code in infinite loop. You can also decide when to stop the script
Related
Background
I'm struggling to find a example of WDT in the way I want to use it. Wondering if I misunderstanding its use.
my python writing is pure hobby, honestly Classes intimidate me.
in short my program reads a number of sensors connected to a raspberry pi and writes the data to a cloud hosted object database.
i have an intermittent error that while I try to figure out I want to implement a based watchdog timer.
This is what I'd like to implement so in the very least I continue to collect and store data.
I've read about the builtin watchdog timer the raspberry pi has built in here: https://diode.io/raspberry%20pi/running-forever-with-the-raspberry-pi-hardware-watchdog-20202/
The problem I want the raspberry pi to reboot if my program hangs, but when that happens the OS is still fine, so the solution in the link above is not effective.
What I'd like to implement:
set the builtin watchdog timer to reboot the raspberry pi after 200 seconds without restarting (patting?) the timer. I think the instructions for this are in the link above.
Within my python script, after I iterate through each sensor, restart (or pat?) the watchdog timer and if 200 seconds elapse between pattings (meaning my program hangs) then RPi reboots.
is this possible?
can someone help me with some simple code? I was hoping to keep this simple and avoid classes and/or threads...
thank you in advance
The WDT is probably not the right solution for the problem you are describing. Based on your description, it sounds like what you have is a program that is intended to run periodically (either on a fixed schedule or in response to some event), and that program currently has a bug that is causing it to hang intermittently and never complete it's task or terminate.
The first and best way to solve that, I'm sure you can guess, is to fix the bug. But your thinking is not unreasonable either, and doing what you describe is very common. There are many valid approaches that will do what you want without the complexity of trying to deal with a hardware timer. One of the easiest is probably to just wrap the program in a shell script and use the timeout command to limit how long it is allowed to execute before it is terminated.
Assuming the script is located at /home/user/my_script.py, and you want to run it every 10 minutes, allowing it 2 minutes before it is killed, this would work:
create a wrapper shell script:
#!/usr/bin/env bash
if ! timeout 120s python /home/user/my_script.py; then
msg="$(date) - script exceeded timeout and was killed"
else
msg="$(date) - script ran successfully"
fi
echo "${msg}" >> /home/user/my_script.log
put the script in a file, say at /home/user/wrapper_script.sh and run chmod 755 /home/user/wrapper_script.sh to make it executable.
schedule the script to run every 10 minutes using cron. At a shell, use crontab -e to edit the users crontab file and add a new line like this:
*/10 * * * * /home/user/wrapper_script.sh
now, every 10 minutes the wrapper will start automatically, and it will kick off the python script. It will wait 2 minutes for the script to stop normally, after which it will reach the timeout and terminate it.
Note: depending on how your python program is written, you might have to use some other options to the timeout command to specify which signal it should use to stop the program. If it is a very basic python script, it should be fine using the default.
Edit: based on the comments, you might be able to just change the command you're using to this:
xterm -T "HMS" -geometry 100x70+10+35 -hold -e sudo timeout 120s /usr/bin/python3 /home/pi/h$
Doing that won't actually schedule the script to run at any fixed interval, so it assumes you already have something in place to handle that. All this will do is make srue that the script is restricted to 120 seconds of run time before it is killed.
I want to be able to run my python script which scans for something related to cryptocurrencies 1 minute after the same script has just been complete. Is this possible? Or could I maybe set a limit before the loop repeats itself or something?
The code I have isn't something I am willing to share due to its sensitive nature. It is a trading bot.
You have a few solutions:
Use a cron job if you are on a unix like platform (you can use this for the syntax, or man cron in the terminal to learn more about it)
Create a long running python script that sleeps for one minute before executing your logic again. Something like this:
import time
while True:
# execute code here
time.sleep(60)
If you are running it on Windows platform ,
You can create a batch file to run your script in cmd using the following command:
start "" "path_to_python.exe" "path_to_python_script"
then create a task in windows task scheduler .
You can refer
https://dev.to/tharindadilshan/running-a-python-script-every-x-minutes-in-windows-10-3nm9 . It might helps.
I have done many research on the forum but I didn't find a clear answer to my question.
I have created a python code which extracts data from a website and put it in a SQL database (with SQLITE).
Now, I would like to make it run 24 hours a day on a server so that it collects data at each moment.
Although I know how to code, I don't have a broad knowledge of IT in general.
Would you know by chance how to solve my problem ?
Edit: I was more thinking about putting my scripts on a cloud server to make it run instead of running it directly from my pc.
Thank you very much.
Lcs
I can think of two options:
1) You use a simple "while true" and "wait" in python, so the script is running constantly.
import time
while True:
# Code
time.sleep(5) # goes to sleep for 5 seconds
You can also do this in shell script (infinite loop+sleep) and then run the program when you want.
2) You can use cronjobs to run the pytho script. You basically have the script the will scrap the website and it will be launched every X seconds/minutes/hours. You can read more about how to use cronjobs in Google
Depends on what system you are using (Unix or windows) you can use either:
1. Windows Task Scheduler for Windows
2. Crontab for Unix
While the copy is in progress, can we put a PC into sleep mode for a specific period of time, then wake up and continue copy using python script? Can you please share the code?
Actually this is possible using shell script.
Most machines manufactured after 2000 support real-time clock wakeup. There are many reasons to do so, one of which would be to record a TV program at a certain time. See ACPI Wakeup.
You'll have to explain what you mean by "While the copy is in progress" - there's not much to go on in the question. While OS drivers have suspend/resume functions, I don't know how to tell the python interpreter to save its state in the middle of running a script and then resume after wakeup. It's possible that the OS suspend/hibernate would fully capture the state of a copy operation and resume without a hiccup, but I wouldn't trust it to do so without substantial testing.
If you have "Wake On Lan" enabled you could potentially run a python script on a different PC and trigger the wake up after your specific period of time.
The scripts would probably need to talk to each other, unless you just do it all at times set in advance.
I have a web crawling python script running in terminal for several hours, which is continuously populating my database. It has several nested for loops. For some reasons I need to restart my computer and continue my script from exactly the place where I left. Is it possible to preserve the pointer state and resume the previously running script in terminal?
I am looking for a solution which will work without altering the python script. Modifying the code is a lower priority as that would mean to relaunch the program and reinvest time.
Update:
Thanks for the VM suggestion. I'll take that. For the sake of completion, what generic modifications should be made to script to make it pause and resumable?
Update2:
Porting on VM works fine. I have also modified script to make it failsafe against network failures. Code written below.
You might try suspending your computer or running in a virtual machine which you can subsequently suspend. But as your script is working with network connections chances are your script won't work from the point you left once you bring up the system. Suspending a computer and restoring it or saving a Virtual M/C and restoring it would mean you need to restablish the network connection. This is true for any elements which are external to your system and network is one of them. And there are high chances that if you are using a dynamic network, the next time you boot chances are you would get a new IP and the network state that you were working previously would be void.
If you are planning to modify the script, few things you need to keep it mind.
Add serializing and Deserializing capabilities. Python has the pickle and the faster cPickle method to do it.
Add Restart points. The best way to do this is to save the state at regular interval and when restarting your script, restart from last saved state after establishing all the transients elements like network.
This would not be an easy task so consider investing a considrable amount of time :-)
Note***
On a second thought. There is one alternative from changing your script. You can try using cloud Virtualization Solutions like Amazon EC2.
I ported my script to VM and launched it from there. However there were network connection glitches after resuming from hibernation. Here's how I solved it by tweaking python script:
import logging
import socket
import time
socket.setdefaulttimeout(30) #set timeout in secs
maxretry = 10 #set max retries
sleeptime_between_retry = 1 #waiting time between retries
erroroccured = 0
while True:
try:
domroot = parse(urllib2.urlopen(myurl)).getroot()
except Exception as e:
erroroccured += 1
if erroroccured>maxretry:
logger.info("Maximum retries reached. Quitting this leg.")
break
time.sleep(sleeptime_between_retry)
logging.info("Network error occurred. Retrying %d time..."%(erroroccured))
continue
finally:
#common code to execute after try or except block, if any
pass
break
This modification made my script temper proof to network failures.
As others have commented, unless you are running your script in a virtual machine that can be suspended, you would need to modify your script to track its state.
Since you're populating a database with your data, I suggest to use it as a way to track the progress of the script (get the latest URL parsed, have a list of pending URLs, etc.).
If the script is terminated abruptly, you don't have to worry about saving its state because the database transactions will come to the rescue and only the data that you've committed will be saved.
When the script is retarted, only the data for the URLs that you completely processed will be stored and you it can resume just picking up the next URL according to the database.
If this problem is important enough to warrant this kind of financial investment, you could run the script on a virtual machine. When you need to shut down, suspend the virtual machine, and then shut down the computer. When you want to start again, start the computer, and then wake up your virtual machine.
WinPDB is a python debugger that supports remote debugging. I never used it, and don't know if remote debugging a running process requires a modification to the script (which is very likely, otherwise it'd be a security issue); but if remote debugging without modifying the script is possible then you may be able to dump the current state of the script to a file and figure out later how to load it. I don't think it would work though.