My webserver is running cpanel and has a Cron job module in it providing a GUI to add/remove/edit cron jobs.
Problem: I need to create a large number of cron jobs (more than 100). Each cronjob simply does a wget <url> to trigger a bunch of PHP functions. What will be the best way to manage them? The current problem with cPanel's Cron GUI is that there will be no organization in the cron jobs. If I have 5 related cron jobs, added seperately admist 100 other unrelated cron jobs, it will get harder to find these cron jobs in the long list of cron jobs.
Should I stick to cPanel's GUI? Or is there an alternative GUI with better features like folders or the ability to move cron jobs up and down the list? Or should I just have 1 cron job, which calls a PHP file that does the various wget in PHP using CURL, with a table and stores the jobs in a MySQL database, essentially creating my own version of cron that runs off a single cronjob which triggers every minute?
Try grouping them.
Say you have 10 groups of ten, depending on how you organise them.
Each one of the cron jobs calls a PHP script that calls 10 other PHP scripts.
If you need them run at different times you could do a simple check with time() to see which scripts should be called.
You could call them the other PHP scripts using cURL.
Make sure to set a large script timeout though, or you might end up with lots of things going wrong.
Could you create one job in CPanel that will run one script.
Then in that script you could create the logic to run the 100 scripts.
If they are to be run at different times then you could use switch(time), or similar to manage execution.
Related
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.
Is it possible to schedule some tasks in php to run automatically on the server at a certain time of the day? . I heard abt cron jobs. is there any way to set it via php code
http://php.net/system lets you to run any command-line utility.
As for the certain command to set a cron job you have either to google a little or ask on serverfault.
I have a Cron Job with PHP which I want to set up on my webhost, but at the moment the script takes about 20 seconds to run with only 3 users data being refreshed. If I get a 1000 users - gonna take ages. Is there an alternative to Cron Job? Will my web host let me run a cron job which takes, for example, 10 minutes to run?
Your cron job can be as long as you want.
The main problem for you is that you must ensure the next cron job execution is not occuring while the first one is still running. You have a lot of solutions to avoid it, basically use a semaphore.
It can be a lock file, a record in database. Your cron job should check if the previous one is finished or not. A good thing is maybe sending you an email if he cannot run because of a long previous job (this way you'll have some notice alerting you that something is maybe getting wrong) By default cron jobs with bad error dstatus on exit are outputing all the standard output to the email of the account running the job, depending on how is configured the platform you could use this behavior or build an smtp connexion on the job (or store the alert in a database table).
If you want some alternatives to cron jobs you should have a look at work queues. You can mix work queues with a cron job, or use work queue in apache-php envirronment, lot of solutions, but the main idea is to make on single queue of things that should be done, and execute them one after the other (but be careful, if you handle theses tasks very slowly you'll get a big fat waiting queue).
A cron job shouldn't have any bearing on how long it's 'job' takes to complete. If you're jobs are taking 20 seconds to complete, it's PHP's fault, not cronjob.
Will my web host let me run a cron job which takes, for example, 10 minutes to run?
Ask your webhost.
If you want to learn about optimizing php scripts, take a look at Profiling PHP Code.
I have 5-6 jobs to be done by cron, and i have separated php scripts for those jobs.
My question is, which one is better, putting all the jobs in one php script or keeping them in separated php files and entering them to crontab separately ?
thx
I'd recommend separate scripts. Primarily it will be much easier to debug/diagnose issues when you get a "failed" email from cron if you know which script was running at the time.
It also allows you to run the other jobs even if one fails more easily.
It also gives you flexibilty to change the timings of different jobs (e.g. suppose you suddenly need to run one every 15mins, but all the others are hourly).
If they all have to run at the same time, then it may be better to write a wrapper script that invokes them all (or enclose them all in one file), and call the one script from cron.
This is especially true if there is an order dependency, such that one script must run before another. Separating these in cron is tricky at best.
If they have to run at different times, then obviously separate cron jobs are warranted.
I'd suggest you to keep all this jobs separately, as this provides you with more flexibility, for example, when setting time.
I have multiple cron tasks which each run multiple shell scripts which contain multiple php/etc. scripts.
Works very nicely.
I have a PHP script that needs to be run at certain times every weekday. Is cron or Windows task scheduler the only way to do this?
Is there a way to set this up from within another PHP script?
Depends how exact the timing needs to be. A technique I've seen used (dubbed "poor man's cron") is to have a frequently accessed script (a site's home page, for example) fire off a task on the first page load after a certain time (kept track of in the database).
If you need any sort of guaranteed accuracy, though, cron or a Windows scheduled task is really the best option. If your host doesn't support them, it's time to get a better one.
Apart from cron or Scheduled Tasks, you can have your PHP script to always run it. The process should sleep (within a loop) until the time has reached. Then, the process could execute the remaining functions/methods. Or, you can set up another script (which will act as a daemon) to check for the time and execute the other script.
Well since the web is a pull mechanism you have to have some sort of action that will trigger a PHP script to execute. cron is an option on *nix and task scheduler on windows. You could also write your own service that has a timer but only if needed, this is common on windows services for updaters, jobs etc.
One way you could do it is in the cron task just call a php script for each action needed. Or one php script that executes other tasks. The problem with web based tasks though such as PHP is timeouts. Make sure your tasks are under 60-90 seconds. If not you might look at using python , perl or ruby or even bash scripts to do the work rather than the PHP script.
cron seems like the best option for you though. You will have to call your script with wget. There are examples here: http://www.thesitewizard.com/general/set-cron-job.shtml
For instance this runs the script everyday at 11:
30 11 * * * /usr/bin/wget http://www.example.com/cron.php
Cron, of course, is by far the best way to schedule anything on *nix.
If this is in a remote server you do not have cron access to, you can setup cron/windows scheduler on your computer, to open a web browser to the page that contains the script you wish to run
You probably want to use cron (or windows scheduled tasks).
If you really wanted, you could set up another php script to run continuously with an infinite loop (with a sleep command inside the loop, say for 30 seconds or so) and then when you reach your desired day/time execute the other script via a shell command call. While possible, I can't think if a single good reason to use this method rather than cron/scheduled tasks
You can write a long running script that runs your main script in predefined times but it will be very unnecessary, error prone, and it will basically be a "cron rewrite in phph".
Using the real cron itself will be easier and a more robust solution. If you are packaging an application, you can put a file in /etc/cron.d which contains a single cron line running your application.
You'll need to use a cron job (under Linux/Unix) or a scheduled task under Windows. You could have another script running on a continuous basis which checks the time and executes a script at a specified interval, but using the OS-supplied mechanism is easier to manage and resilient to restarts, etc.
The Uniform Server project has some good suggestions on mimicking cron in environments where cron is unacceptable. Still though, if cron is at all an option, use it.