I am using Cakephp.
I want to run scheduled jobs.
Here's the situation:
User set time for some task on UI (say 1 week).
When the time is over, I want to execute some specific task. Meanwhile, the user can also change the time, and the task should be executed at updated time.
What is the best way (and reliable) to achieve this?
PS: Complexity is not the issue. But the task must always run after specific time under all circumstances.
Set the execution date in your table in a field
Set a status (pending) as well
Run a cron job that runs a CakePHP shell every X seconds or minutes, whatever you need OR create a shell that keeps running all time and check the records every X seconds in a loop.
The shell will process tasks that are configure for an execution date lower than the current date
Set the status to success or failed depending on the outcome
It's up to you how you want to handle failed tasks and if it's OK if a task executes 10secs later than configured or 10 minutes. There are multiple factors that play into this: Your interval of the cron job / query against the table. Do they have to processed in parallel? Is it OK to process them after each other? Your information is to vague.
The way to do that in CakePHP is to create a shell and run it with Cronjobs.
Related
Currently, I have done the following:
I created one scheduled task which runs daily to get the Scheduled time from Mysql DB for the currentdate and store it into the .txt file
SELECT workflow_id, DATE_FORMAT(schedule_datetime,'%H:%i')TIMEONLY FROM scheduling_event
where DATE(schedule_datetime) = CURDATE()
Created one more scheduled task that runs each 5mins to check if the scheduled time present in the .txt file matches the CURRENT TIME if yes then it calls the scheduled_program.php file.
The issue here is - this is not an efficient way if nothing is scheduled on the current date. So Is there any way to create/update a dynamic scheduled task instead of running each 5mins? ie: the first scheduled task will run and take the scheduled time on the current date then it will create a task based on the scheduled time. if the day ends delete all the scheduled tasks for the day.
Note: Number of the scheduled task is not fixed. imusing Windows 10, php7.
I am trying to achieve, run a scheduled_program php file on schedule Date and TIME
It looks like you're trying to solve a problem that's not serious. I guess you don't want to waste your computer's time running a cron job every five minutes if it has nothing to do.
But here's the thing:
a cron job
that runs a php program
that does a single query
to retrieve a list of workflows
and run them
has negligible cost if you run the cron job every five minutes, or even every single minute, and there are no workflows to run.
On the other hand, debugging and troubleshooting cronjobs is hard, especially in production.
So, I respectfully suggest you keep this system as simple as you possibly can. You will have to explain it over the telephone to somebody in the middle of the night at least once. That's the unfortunate truth of scheduled tasks. The dynamic scheduled task system you propose is not simple.
I am working on a web application that requires php code to run at a specific date/time.
Some hypothetical examples would be sending a user an email at 09:00 on their birthday or modifying a database entry (mySQL) at a predetermined date and time.
What would be the conventional way to implement this kind of scheduling feature?
I've seen cron-jobs been used for similar requirements but would this be feasible for a large amount of scheduled tasks?
Depends on the size of your project, but usually we don't have one script do all the cron jobs, because things need to happen at different times. Some emails might send at 9pm, some database cleanup might happen at midnight, and sessions might expire every few minutes. The best thing to do is set up separate cron jobs for each thing. There are a couple exceptions for this:
Some tasks need to run very frequently, like every 30 seconds. For that we set up a cron task which checks "ps" to see whether its own process is already running, and have it just wait 30 seconds and loop.
Some tasks make more sense to run when a queue is full. For that we trigger the task when a certain user-based script executes the 100th or 200th or 300th time. For example when a user pings 100 times without doing anything else, we log them out without using a cron task, but there is a separate cron task which checks if they've been inactive for 10 minutes.
I have a website that users create their own tasks to be run at a specific time.
At the moment, when the user clicks create task it will add to the database table 'tasks'.
I then have a cron job, which runs every 15mins. It gets all the entries in the table and checks first whether it has been run today using the date time. (every midnight, another cron runs through and resets all these values). If it has not ran this day, it will then run it and afterwards change the value to ran.
The cron job does this by running php file on my server that checks for tasks, and then uses a simple foreach statement.
At the moment, there are only 11 users and my server seems fine. I am wondering what will happen with lets say 10,000 users.
Is this an efficient way to handle thousands of cron jobs? How yould you go about running this?
Cron is not running at specified time in moodle?
1.I just created an cron job like a
function cron(){} in block_plugin and i written an code to insert records in db and i set time $plugin->cron= 1*60; in version.php. its inserting data into db when i am running mysite.com/admin/cron.php.
2.Its not working for every specific time(automatically for every 1 min).I checked db after 1min without running yoursite.com/admin/cron.php file its ideal. please help in it.
If you are not manually running admin/cron.php, then have you set up something to automatically call this on a schedule? (Or admin/cli/cron.php)?
If you have not set up an automatic process to run the Moodle cron and have not called it manually, then none of the cron processes will happen.
Note that specifying 60 seconds is the minimum time between your code running - it will depend on how long the other cron processes take (I've seen large sites where cron can take 30-40 min to run at times) and how often the automated process calls it (could be every 1 min, but many sites set it to every 5-10min, or longer, to reduce server load).
I'm in need of a way to create dynamic, one-off cron jobs to execute tasks at different times. Ideally, I would like to achieve this using PHP, so that when a user completes a certain action, the cron job is created and scheduled for a time that is calculated based on the time that the user completes said action. At any one time, there could be multiple cron jobs scheduled at once for different times. These cron jobs also need to be deleted upon completion.
I have tried searching around for something appropriate, however haven't encountered anything that works as I need. If anybody could point me in the right direction, that would be greatly appreciated.
Cheers
A possible solution:
Setting a Cron job that calls to CronJobManager.php every second.
Just make a regular daemon that calls for the CronJobManager.php.
Create a cronjob table in your database
The cron job table should contain these basic fields: path (to php file), run_time(datetime), last run (datetime) and type (like suicidal, if as you explain you want some cron jobs to delete themselves)
Connect CronJobManager.php with the cronjob table
Every time CronJobManager.php runs (that is, every second), loads the cron jobs. Then, comparing "now"'s time with each cron job's run_time you'll get which cron jobs to run.
For example, if cron job "foo" run_time is set to 18/04/2014 22:02:01, CronJobManager will run it when reaching that moment.
Notice that if Cron jobs executing time needs a lot of time, they'll get delayed and eventually a second or two will get lost.
Now, for every cron job that needs an execution, you would execute the related php file of that cron job, indicated in the path.
This is a general idea, and of course you would have to extend it with for example cron job states (idle, running, stop, etc).
In order to delete cron jobs you would implement this feature in the cron job object.
That is: the Cron Job class, once it has executed what it had to do, it would check its type (as defined in database). If it is 'suicidal', then it would delete the database row.
UPDATE
I updated the answer but I want to note something. If what you need is several cron jobs to run at once, in a specific second with 0 delay, then you need a cron job per task out of php that runs a specific file.
To achieve this functionality, you need to have a daemon that is running all the time that checks for these dynamic jobs and launches them. The setup is a tad complicated to put together, but if you are ready for such an endeavor, you can use the project PHP Resque Scheduler.
https://github.com/chrisboulton/php-resque-scheduler
You start up a daemon that runs all the time and then you can add jobs to a dynamic queue to be executed at any specified time in the future. I think you will find this suitable to everything you are looking to do.