So I have database of users which have a reminderTime field which currently is just a string which looks like that 07:00 which is a UTC time.
In the future I'll have a multiple strings inside reminderTime which will correspond to at which time the user should receive a notification.
So imagine you logged into an app, set a multiple reminders like so 07:00, 15:00, 23:30 and sent it to server. The server will save those inside a database and run a task and send a notification at 07:00 then at 15:00 and so on. So later a user decided that he will no longer wants to receive notifications at 15:00 or change it to 15:30 and we should adapt to that.
And each user has a timezone, but I guess since reminderTime is already in UTC I can just create a task without looking at timezone.
Currently I have a reminderTime as number and after client sends me a 07:00 I convert it to seconds, but as I understand I can change that and stick to string.
All my tasks are running with Bull queue library and Redis. So as I understood the best scalable approach is to take reminderTime and just create notifications for each day at a given time and just run the task, the only problem is that should I save them to my database or add a task to a queue in Bull. The same will be for multiple times.
I don't understand how should I change already created tasks inside Bull so that the time will be different and so on.
Maybe I could just create like a 1000 records at which time user should receive a notification inside my database. Then I create a repeatable job which will run like every 5 minutes and take all of the notifications which should be send in the next couple of hours and then add them to a Bull queue and mark it that it was sent.
So basically you get the idea, maybe it could be done a little bit better.
Unless you have really a lot of users, you could simply create a schedule-like table in your DB, which is simply a list of user_id | notify_at records. Then, run a periodic task every 1-5 minutes, which compares current time and selects all the records, where notify_at is less than the current time.
Add the flag notified, if you want to send notifications more than once a day to ignore ones that was already sent. There is no need to create thousands of records for every day, you can just reset that flag once a day, e.g. at 00:00 AM.
It's ok that your users wont recieve their notifications all at the same time, there could be little delays.
The solution you suggested is pretty much fine :)
Related
Condition is like this.
How to allow a user to insert a document(data) in the collection(table) which will expire at 90 days .On the 85th day and on the 90th day Server will send a notification as a reminder for expiry date and in 90th day it be will be sent to the trash for 30 days and again in the trash server will give notification on the 28th day (118th total life of data )and then on the 30th day as reminder sent notification that it will be deleted from the database and be deleted.
2.How can i automatically change the document value like on the 60th day a document in the database will go from (visible:true) to (visible:false) after when the user extends the time to 90th from 60 days then it will changed to (visible:true) again.The problem is just here to change the value to false automatically without user interaction with the app on 60th day.
i am currently trying to do it on Node.js using express.
The core MongoDB server does not implement scheduling, but if you use Atlas you can use Atlas Triggers.
Currently, I'm working on a project that requires a window of time to be selected that is used as a valid window to trigger an event within. This window is selected by the user as a start time (24 hour time), end time (24 hour time), and a timezone. My goal is to then be able to convert these times into UTC based on the offset from the provided timezone and save into MySQL.
The main problem is I have set up the entire flow to deal with time-only data types from the mobile app all the way back to the MySQL database. I have been trying to figure out a solution that won't require changing all those data types to include date and time which would require changes in many parts of the project.
Can I make this calculation without dealing with the date? I don't believe I can as timezone offsets range from -12:00 to +14:00 which would push some windows to the next or previous days when turned into UTC.
Is the correct approach to add in the date component and then continue to update it as time progresses? I also want to ensure daylight savings doesn't create errors.
Ultimately I would like the best approach to take so if I have to change a lot now I'd rather do that then deal with a headache later. Any thoughts would be greatly appreciated!
How do I make the time expired, suppose I made an article, to be able to make it again, had to wait for 15 hours, I was using nodejs and node-datetime.
I think the current time plus 15 hours, but how?
thanks before
I suppose you have a database with the articles, so, just save the creation date in each article, and when a user requests the access to create a new article, verify if his last article is more than 15 hours old
I want to make schedules that depend on entries of a database to schedule cron jobs. Like if there's an entry in database with a timestamp 2:00 PM, 3rd of Apr, I want to send a mail to users on 2nd of Apr. I also want to send notifications at 1:55 PM 3rd of Apr.
So, this means I have to look into the database, find the entries after the current times tamp, see if they suit the criteria for notification (like 5 minutes to time stamp or 1 day to time stamp) and send the notification or mail. I'm only worried that every one minute seems like too much overload. Are the AWS web workers built for this sort of thing?
Any suggestions on how this can be accomplished?
I don't think crontab will be the best choice but if you're familiar with it, it's fine.
First you should estimate how frequently your entries are created. If, let's say, only a couple of hundred a day. My suggestion is to create the crontab job right after the entry is created. But if more than a hundred a minutes, pooling will be fine.
But there are also side effects, like canceling or updating the cron job .
I think it's better to use a proper MQ.
We need to rebill x amount of customers on any given day.
Currently, we run a cron every 5 mins to bill 20 people/send invoice etc
However, when the number of customers grows, extending to 100 people per 5 min may result in the cron overlapping and billing customers twice.
I have two thoughts:
Running the cron once, but making it sleep x amount after 20 billed/invoiced so that we dont spam the API.
Using a message queue where people are added to the queue and then "workers" process the queue. The problem is I have no experience in this, so not sure what is the best route to take.
Does anyone have any experience in this?