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.
Related
I have a PHP script that needs to be executed by the end of every month. How would I do that without using cron on Unix-like systems or Task Scheduler on Windows systems? Isn't there some built-in feature in php for this? Because using cron/scheduler is not that much portable way IMO.
The only other way is by triggering it when the website is loaded. For example, you'd store the time the script was last run. Then every time a page is loaded, you'd check if it's time to run it. If so, then you would run it as part of the page load. Of course, this depends on (1) the task being a very quick one, and (2) that the task doesn't have to be run exactly on schedule, down to the second. This is basically how wp_cron() works in Wordpress.
Php is just a scripting language, not a process that is aware of time and may trigger events at desired moments.
Once you settle in a server, you don't have to worry about portability: migrating to another place won't be an automatic process because the environment could be very different.
So stick with cron, or write yourself a OS-agnostic layer.
In the system i worked on, i had a little module that had the last running of the script saved, and on every running of the main script, it checked, if the script shouldn't have been run. In case it should have, it did before anything else executed, so the system had the right data anyway, even if the periodical script wasn't run "on time". It also checked if the script shouldn't have been run more than once, and ran it several times, if needed.
A bit crude, but produces the right results without anything but PHP/mysql.
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.
I'm building a system that watches a queue and activates a set of tasks on a regular interval.
I'm interested in running multiple instances of my processing "bots" based on how many items are in the queue. So if there are 5 items I'll run two bots and if their are 10 I'll run four.
I know how to run multiple instances from CLI (manually), but how would I do this as a function of my application? And how would I properly track the creation and destruction of these bots?
It seems like cron (*nix) or task scheduler (windows) would be what you need.
http://en.wikipedia.org/wiki/Cron
http://msdn.microsoft.com/en-us/library/aa383614%28VS.85%29.aspx
These can run a PHP script that determine how many "bots" need run, calculations, etc. Anything PHP is capable of.
Also, for running the multiple bots in the background (after the main controller script has finished executing) you may want to look at PHP process forking.
You might also want to look at gearman ( http://gearman.org/ )
I am using MYSQL as my database and PHP as my programming language.I wanted to run a cron job which would run until the current system date matches the "deadline(date)" column in my database table called "PROJECT".Once the dates are same an update query has to run which would change the status(field of project table) from "open" to "close".
I am not really sure if cron jobs are the best way or I could use triggers or may be something else.Also I am using Apache as my web server and my OS is windows vista.
Also which is the best way to do it? PHP scheduler or cron jobs or any other method? can anybody enlighten me?
I think your concept needs to change.
PHP cannot schedule a job, neither can MySQL. Triggers in MySQL execute when a mysql query occurs, not at a specific time. Neither
This limitation usually isn't a problem in web development. The reason is because your PHP application should control all data going in and out. Usually, this means just the HTML that displays that data, or other formats to users, or other programs.
In your case you can think about it this way. The deadline is a set date. You can treat it as data, and save it to your database. When the deadline occurs is not important, it is that the data you have sent in your database is viewed correctly.
When a request is made to your application, check if the date of the deadline is in the past, if it is, then display that the project is closed - or update that the project is closed, just before display.
There really is no reason to update data independantly of your PHP application.
Usually, the only things you want to schedule are jobs that would affect your application in terms of load, or that need to be done only once, or where concurrency or time is an issue.
In your case none of those apply.
PS: I haven't tried PHPscheduler but I can guess it isn't a true scheduler. Cron is a deamon that sleeps until a given task is due in its queue, executes the task, then sleeps till the next one is due (at least thats what it does in the current algorithm). PHP cannot do that without the sockets and fork extensions, as special setup. So PHPscheduler is most likely just checking if a date for a task has expired, on each load of a webpage (whenever PHP executes a page). This is no different then you just checking if the date on the project has expired, without the overhead of PHPScheduler.
I would always go for a cron job for anything scheduling related.
The big bonus point is that you can echo info out as well and it get's emailed to you.
You'll find once you start using cronjobs, it's hard to stop.
cron does not exist, per se, in vista, but what does exist is the standard windows scheduling manager which you can run with a command line like "php -q -f myfile.php" which will execute the php file at the given time.
you can also use a port of the cron program, there are many out there.
if it is not critical to the second, any windows scheduling application will do, just be sure to have you PHP bin path in your PATH variable for simplicity.
For Windows CRON jobs I cannot recommend PyCron enough.
While CRON and Windows Scheduled Tasks are the tried and true ways of scheduling jobs/tasks to run on a regular basis, there are use cases where having a different scheduled task in CRON/Windows can become tedious. Namely when you want to let users schedule things to run, or for instances where you prefer simplicity/maintainability/portability/etc or all of the above.
In cases where I prefer to not use CRON/Windows for scheduled tasks, I build into the application a task scheduling system. This still requires 1 CRON job or Windows Task to be scheduled. The idea is to store Job details in the database (job name, job properties, last run time, run interval, anything else that is important for your implementation). You then schedule a "Master" job in CRON or Windows which handles running all of your other jobs for you. You'll need this master job to run at least as often as your shortest interval; if you want to be able to schedule jobs that run every minute the master job needs to run every minute.
You can then launch each scheduled job in the background from PHP with minimal effort (if you want). In memory constrained systems you can monitor memory usage or keep track of the PIDs (various methods) and limit to N jobs running at a given time.
I've had a great deal of success with this method, YMMV however based on your needs and your implementation.
how about PHPscheduler..R they not better than cronjobs? I think crons would be independent of the application hence would be difficult if one has to change the host..i am not really sure though..It would be great if anyone can comment on this!! Thanks!
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.