So I am making a website, and something that required for part of the security is having a waiting period when trying to do something, for example trying to delete something, this would help incase someone's account was stolen and someone tried to ruin their account.
I'm already using SQLite so I'm going to create a table in there where scheduled events will be defined.
What I'm wondering is what is the best way to constantly check these scheduled events, it may also be important to note I want to check at least every hour. My immediate thought was creating a separate thread and running a function on there with a while loop in it which will constantly run a chunk of code with a time.sleep(3600) at the end of the function, like this:
def check_events(self):
while True:
# code
time.sleep(3600)
I'm not sure though if this is the most efficient way of doing it.
That function currently is inside my website code class hence the self, is that something I need to put on the outside or no?
I would either create a cron job on your server (which is the most straightforward)
or use a schedule module to schedule your task, see example:
import time
import schedule
from sharepoint_cleaner import main as cleaner
from sharepoint_uploader import main as uploader
from transfer_statistics import main as transfer_stats
schedule.every(1).hours.do(uploader)
schedule.every(1).hours.do(transfer_stats)
schedule.every().sunday.do(cleaner)
while True:
schedule.run_pending()
time.sleep(10)
https://github.com/ansys/automatic-installer/blob/4d59573f8623c838aadfd49c312eeaca964c6601/sharepoint/scheduler.py#L3
Related
i have one httpTrigger where i have implemented cache we have a requirement where we have to update cache after 2 hr.
Solution 1:
we can expire the cache after 2 hour.. but we don't want to use this solution
Solution 2:
we want a function to get triggered (update_cache()) after every 2 hour.
I find out some library
But i am unable to get how i can implement this..
# i want to trigger this function every 2 hour
def trigger_scheduler_update():
logging.info("Hi i am scheduler and got triggered...")
schedule.every(2).hours.do(trigger_scheduler_update)
But the problem i am facing here is we have to write this kind of code.
# ref: https://www.geeksforgeeks.org/python-schedule-library/
while True:
# Checks whether a scheduled task
# is pending to run or not
schedule.run_pending()
time.sleep(1)
As its an infinite loop i can place it in http trigger is there a way i can implement a scheduler that run after 2 hr.
i don't know that can it be done using threading?
i found one more library but looks like it also won't work.
Your function is shut down after a period of time, unless you are on a premium plan. Even then you cannot guarantee your function keeps on running.
What cache are you referring to?
Note that you cannot do threading in azure functions and you shouldn't actually. Abandon the idea of refreshing the cache from your httpTrigger function and create a separate scheduleTriggered function to update the cache that your http function is using.
I have a program that constantly runs if it receives an input, it'll do a task then go right back to awaiting input. I'm attempting to add a feature that will ping a gaming server every 5 minutes, and if the results every change, it will notify me. Problem is, if I attempt to implement this, the program halts at this function and won't go on to the part where I can then input. I believe I need multithreading/multiprocessing, but I have no experience with that, and after almost 2 hours of researching and wrestling with it, I haven't been able to figure it out.
I have tried to use the recursive program I found here but haven't been able to adapt it properly, but I feel this is where I was closest. I believe I can run this as two separate scripts, but then I have to pipe the data around and it would become messier. It would be best for the rest of the program to keep everything on one script.
'''python
def regular_ping(IP):
last_status = None
while True:
present_status = ping_status(IP) #ping_status(IP) being another
#program that will return info I
#need
if present_status != last_status:
notify_output(present_status) #notify_output(msg) being a
#program that will notify me of
# a change
last_status = present_status
time.sleep(300)
'''
I would like this bit of code to run on its own, notifying me of a change (if there is one) every 5 minutes, while the rest of my program also runs and accepts inputs. Instead, the program stops at this function and won't run past it. Any help would be much appreciated, thanks!
You can use a thread or a process for this. But since this is not a CPU bound operation, overhead of dedicating a process is not worth it. So a thread would be enough. You can implement it as follows:
import threading
thread = threading.Thread(target=regular_ping, args=(ip,))
thread.start()
# Rest of the program
thread.join()
I'm making a personal assistant like Google Assistant or Siri, and I want the user to be able to set reminders. For example, if they type "Remind me to wash the dishes at 5pm" I would like it to pop up later and remind them. However I also want code to be able to run while waiting, so you could set multiple reminders or check the weather.
time.sleep simply stops the program. I'm pretty sure there's a way to do it with threads but I'm not sure how. Please help!
Python threading has a Timer which does exactly what you ask for:
from datetime import datetime
from threading import Timer
def create_notification(time, name):
delay = (time - datetime.now()).total_seconds()
Timer(delay, show_notification, args=[name]).start()
def show_notification(name):
print(f'notification: {name}!')
create_notification(datetime(2034, 1, 1), 'Hello future!')
One thing to watch out for is this approach creates a single thread for each event (which doesn't scale well for lots of events). This also suffers from the problem that if the user closes your program, your program crashes, computer shuts down, power loss, etc. you lose all of your notifications. If you need to handle this, then save them to a file. If you need the notifications to show up even when your program isn't running look into solutions provided by the OS like cronjobs.
I'm using AWS python API (boto3). My script starts a few instances and then waits for them to come up online, before proceeding doing stuff. I want the wait to timeout after a predefined period, but I can't find any API for that in Python. Any ideas? A snippet of my current code:
def waitForInstance(id):
runningWaiter = self.ec2c.get_waiter("instance_status_ok")
runningWaiter.wait(InstanceIds = [id])
instance = ec2resource.Instance(id)
return instance.state
I can certainly do something like running this piece of code in a separate thread and terminate it if needed, but I was wondering whether there is already a built in API in boto3 for that and I'm just missing it.
A waiter has a configuration associated with it which can be accessed (using your example above) as:
runningWaiter.config
One of the settings in this config is max_attempts which controls how many attempts will be tried before giving up. The default value is 40. You can change that value like this:
runningWaiter.config.max_attempts = 10
This isn't directly controlling a timeout as your question asked but will cause the waiter to give up earlier.
Why not check the instances status from time to time?
#code copy from boto3 doc
for status in ec2.meta.client.describe_instance_status()['InstanceStatuses']:
print(status)
refence : http://boto3.readthedocs.org/en/latest/guide/migrationec2.html
BTW, it is better to use tag naming for all the instances with a standard naming convention. Query any aws resources with its original ID is a maintenance nightmare.
You could put a sleep timer in your code. Sleep for x minutes, check it to see if it is finished and go back to sleep if not. After y number of attempts take some sort it action.
I want to check users' subscribed dates for certain period. And send mail to users whose subscription is finishing (ex. reminds two days).
I think the best way is using thread and timer to check dates. But I have no idea how to call this function. I don't want to make a separate program or shell. I want to combine this procedure to my django code. I tried to call this function in my settings.py file. But it seems it is not a good idea. It calls the function and creates thread every time I imported settings.
That's case for manage.py command called periodically from cron. Oficial doc about creating those commands. Here bit more helpful.
If you want something simpler then django-command-extensions has commands for managing django jobs.
if you need more then only this one asynchronous job have a look at celery.
using Django-cron is much easier and simple
EDIT: Added a tip
from django_cron import cronScheduler, Job
class sendMail(Job):
# period run every 300 seconds (5 minutes)
run_every = 300
def job(self):
# This will be executed every 5 minutes
datatuple = check_subscription_finishing()
send_mass_mail(datatuple)
//and just register it
cronScheduler.register(sendMail)