Railway•8mo ago

Railway cron schedule skipped

Project ID: 5510af11-7ac6-4c46-b964-e91edd728850 This morning my cron schedule didnt run at 10 as planned (see attached) The logs show the below message and the cron job is shown as "active". The error message is typical and doesnt normally stop the git repo from running. Could anyone suggest why the code didnt execute? Quite new to this

16 Replies

Percy•8mo ago

Project ID: 5510af11-7ac6-4c46-b964-e91edd728850

buddyswift•8mo ago

update: this cron task just completed but it took 3 hours to run instead of 30 seconds. any ideas why this could happen?

buddyswift•8mo ago

Brody•8mo ago

you're running a bot in a cron schedule?

buddyswift•8mo ago

Yeah it’s just a custom discord bot that posts some information at fixed intervals

Floris•8mo ago

bots are usually made to run in a constant event loop, if you do insist on closing it each time over just an internal cron in your code make sure you close your discord event loop i use this myself py to cron every day at 6 AM, be wary of railways timezone in UTC, if you are on a different timezone it will cron on its correct time but incorrect for your timezone

import asyncio
from datetime import datetime, timedelta

async def run_cron_scheduler():
    print("cron scheduler started")

    target_time = datetime.now().replace(hour=6, minute=0)
    if target_time < datetime.now():
        target_time += timedelta(days=1)
        print(target_time)

    while True:
        now = datetime.now()
            
        if did_event_happen(True):
            # you can asyncio sleep for your interval to avoid busy waiting
            # i use this to cache the last unix run time to verify if my cron is behaving
            # correctly to error handle if it is not
            continue

        if target_time <= now:
            
            do_something() # call your function here

            did_event_happen(False) # i mark here that the event has happened

        if now >= target_time:
            target_time += timedelta(days=1)
            print(target_time)

        await asyncio.sleep((target_time - now).seconds)

import asyncio
from datetime import datetime, timedelta

async def run_cron_scheduler():
    print("cron scheduler started")

    target_time = datetime.now().replace(hour=6, minute=0)
    if target_time < datetime.now():
        target_time += timedelta(days=1)
        print(target_time)

    while True:
        now = datetime.now()
            
        if did_event_happen(True):
            # you can asyncio sleep for your interval to avoid busy waiting
            # i use this to cache the last unix run time to verify if my cron is behaving
            # correctly to error handle if it is not
            continue

        if target_time <= now:
            
            do_something() # call your function here

            did_event_happen(False) # i mark here that the event has happened

        if now >= target_time:
            target_time += timedelta(days=1)
            print(target_time)

        await asyncio.sleep((target_time - now).seconds)

oh i see you're on .js, my bad if you want me to write a nodejs version let me know but its pretty similair

buddyswift•8mo ago

@Morpheus thanks for taking the time bud i've attached my git code which seems to run pretty well when its triggered within railway and im using Railways native cron scheduler to execute the js from my github repo what i dont understand is what triggers the code to run, is it permanently active once deployed? i believed i needed to use an external scheduler to run the script. very new to this as you can tell and first time coding in js

message.txt

buddyswift•8mo ago

this is the cron schedule in railway

buddyswift•8mo ago

sorry for all the debugging being included, the js is much simpler than it appears

Brody•8mo ago

can you tell us why you are running your bot at those specfic times and not 24/7?

buddyswift•8mo ago

The bot is hosting a competition where new challenges need to be posted at discrete intervals. I wasn’t aware of how to keep the script running 24/7 so opted to schedule it to run every 6 hours posting some corresponding data from a postgres db If it was running 24/7, what would the trigger be to post at the correct times?

Floris•8mo ago

I have sent you The code in Py of how i handle this In simple english, you initialize an event loop that just runs infinitely and you define 4 CRON times now in this event loop you just constantly compare the current time with one of the 4 CRON times, when your CRON is triggered you can cache or save the time of triggering somewhere so now in the beginning of your script you just check if the last run time was <24 hrs ago to avoid firing the CRON multiple times and you just do this for all 4 of your times im sure NodeJs has libraries for this too but this is a high level overview .

buddyswift•8mo ago

Thanks dude

Floris•8mo ago

if you need help with the code in nodejs let me know ill code it for u

buddyswift•8mo ago

It’s good practice for me in js

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Railway cron schedule skipped