Develop Reference

Using apscheduler in a periodic short-running script

My (simplified and generalized) need is the following:
Given is a main program which starts my Python script every minute. By design, this script is intended to be a short-runner.
Its goal is to call different web hooks - not on every call, but in individual intervals, e.g. every 5 minutes. (The script can read the configuration from a file.)
So it is not possible for me to use apscheduler in a permanent running program.
On the contrary, the program itself must determine on each run which API calls are overdue and have to be made now.
Is it possible to use apscheduler for this?

How to schedule a script to run periodically?

I have a task to write a Python script which has to parse a web-page once a week. I wrote the script but do not know how can I make it to work once a week. Could someone share an advice and write possible solution?

Have a look at cron. Its not python, but fits the job much better in my opinion. For example:
#weekly python path/to/your/script
A similar question was discussed here.

Whether the script itself should repeat a task periodically usually depends on how frequently the task should repeat. Once a week is usually better left to a scheduling tool like cron or at.
However, a simple method inside the script is to wrap your main logic in a loop that sleeps until the next desired starting time, then let the script run continuously. (Note that a script cannot reliably restart itself, or showing how to do so is beyond the scope of this question. Prefer an external solution.)
Instead of
def main():
...
if __name__ == '__main__':
main()
use
import tim
one_week = 7 * 24 * 3600 # Seconds in a week
def main():
...
if __name__ == '__main__':
while True:
start = time.time()
main()
stop = time.time()
elapsed = stop - start
time.sleep(one_week - elapsed)

Are you planning to run it locally? Are you working with a virtual environment?
Task scheduler option
If you are running it locally, you can use Task scheduler from Windows. Setting up the task can be a bit tricky I found, so here is an overview:
Open Task Scheduler > Create Task (on right actions menu)
In tab "General" name the task
In tab "Triggers" define your triggers (i.e. when you want to schedule the tasks)
In tab "Actions" press on new > Start a program. Under Program/script point to the location (full path) of your python executable (python.exe). If you are working with a virtual environment it is typically in venv\Scripts\python.exe. The full path would be C:\your_workspace_folder\venv\Scripts\python.exe. Otherwise it will be most likely in your Program Files.
Within the same tab, under Add arguments, enter the full path to your python script. For instance: "C:\your_workspace_folder\main.py" (note that you need the ").
Press Ok and save your task.
Debugging
To test if your schedule works you could right click on the task in Task scheduler and press on Run. However, then you don't see the logs of what is happening. I recommend therefore to open a terminal (eg cmd) and type the following:
C:\your_workspace_folder\venv\Scripts\python.exe "C:\your_workspace_folder\main.py"
This allows you to see the full trace of your code and if its running properly. Typical errors that occur are related to file paths (eg if you are not using the full path but a relative path).
Sleeping mode
It can happen that some of the tasks do not run because you don't have administrator privileges and your computer goes in sleeping mode. What I found as a workaround is to keep the computer from going into sleeping mode using a .vbs script. Simply open notepad and create a new file named idle.vbs (extension should be .vbs so make sure you select all programs). In there paste the following code:
Dim objResult
Set objShell = WScript.CreateObject("WScript.Shell")
Do While True
objResult = objShell.sendkeys("{NUMLOCK}{NUMLOCK}")
Wscript.Sleep (60000)
Loop

How do I have a bash script continually run during business hours?

I have a Python program I run at all times of the day that alerts me when something I am looking for online is posted. I want to give this to my employees but I only want to have it email them during business hours.
I have a Ubuntu server and use a .sh. I have a command in crontab that runs on startup.
How do I make my command run from 9-5?

You could create a cronjob that starts the script every 5 minutes (or whatever often you want it to run) and additionally modify the script such that it creates a .lock file which it removes on exiting, but if it encounters it at the beginning it won't do anything (this way you don't have a long-running script active multiple times).

Methods to schedule a task prior to runtime

What are the best methods to set a .py file to run at one specific time in the future? Ideally, its like to do everything within a single script.
Details: I often travel for business so I built a program to automatically check me in to my flights 24 hours prior to takeoff so I can board earlier. I currently am editing my script to input my confirmation number and then setting up cron jobs to run said script at the specified time. Is there a better way to do this?
Options I know of:
• current method
• put code in the script to delay until x time. Run the script immediately after booking the flight and it would stay open until the specified time, then check me in and close. This would prevent me from shutting down my computer, though, and my machine is prone to overheating.
Ideal method: input my confirmation number & flight date, run the script, have it set up whatever cron automatically, be done with it. I want to make sure whatever method I use doesn't include keeping a script open and running in the background.

cron is best for jobs that you want to repeat periodically. For one-time jobs, use at or batch.

Uploading code to server and run automatically

I'm fairly competent with Python but I've never 'uploaded code' to a server before and have it run automatically.
I'm working on a project that would require some code to be running 24/7. At certain points of the day, if a criteria is met, a process is started. For example: a database may contain records of what time each user wants to receive a daily newsletter (for some subjective reason) - the code would at the right time of day send the newsletter to the correct person. But of course, all of this is running out on a Cloud server.
Any help would be appreciated - even correcting my entire formulation of the problem! If you know how to do this in any other language - please reply with your solutions!
Thanks!

Here are two approaches to this problem, both of which require shell access to the cloud server.
Write the program to handle the scheduling itself. For example, sleep and wake up every few miliseconds to perform the necessary checks. You would then transfer this file to the server using a tool like scp, login, and start it in the background using something like python myscript.py &.
Write the program to do a single run only, and use the scheduling tool cron to start it up every minute of the day.

Took a few days but I finally got a way to work this out. The most practical way to get this working is to use a VPS that runs the script. The confusing part of my code was that each user would activate the script at a different time for themselves. To do this, say at midnight, the VPS runs the python script (using scheduled tasking or something similar) and runs the script. the script would then pull times from a database and process the code at those times outlined.
Thanks for your time anyways!