Job scheduling for the PHP Fat-Free Framework
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README.md

Cron

Job scheduling for the PHP Fat-Free Framework

This plugin for Fat-Free Framework helps you control job scheduling directly from your web app.

Installation

To install this plugin, just copy the lib/cron.php file into your lib/ or your AUTOLOAD folder.

Operation and basic usage

This plugin provides your app with an external interface to run scheduled jobs. The interface consists in 2 routes automatically added to your app:

  • GET /cron checks for due jobs and executes them
  • GET /cron/@job triggers a specific job

By default, this interface is accessible in CLI mode only and is meant to be called by the server job scheduler:

  1. Unix cron or Windows Task Scheduler calls index.php /cron every minute (or at a slower rate).
  2. index.php /cron checks for due jobs at that time and executes them, asynchronously if possible.

Step 1:

Configure your server job scheduler so that it calls php index.php /cron every minute.

Here's how to do it on a *nix server, assuming that your application resides in /path/to/app/index.php:

  • create a file named, for example, mycrontab, containing the following line:
* * * * * cd /path/to/app; php index.php /cron
  • configure cron with it, using the following command:
crontab mycrontab

NB1: depending on your hosting, you may need to ask your provider to perform that step.

NB2: if your cron job needs disk write access, take care about the UNIX user permissions.

Step 2:

Instantiate the Cron class and define the list and frequency of jobs with the following commands:

//index.php
$f3=require('lib/base.php');
...
$cron=Cron::instance();
$cron->set('Job1','App->job1','@daily');
$cron->set('Job2','App->job2','@weekly');
...
$f3->run();

That's it!

Job1 will run every day and Job2 every week.

Schedule format

Crontab

Each job is scheduled using the (nearly) standard crontab format, which consists of 5 fields separated by spaces:

 * * * * *
 │ │ │ │ │
 │ │ │ │ │
 │ │ │ │ └───── day of week (0 - 6) (0 to 6 are Sunday to Saturday)
 │ │ │ └────────── month (1 - 12)
 │ │ └─────────────── day of month (1 - 31)
 │ └──────────────────── hour (0 - 23)
 └───────────────────────── min (0 - 59)

Each field may be:

  • a *, meaning any value
  • a number: 3
  • a range: 1-4 (equals 1,2,3,4)
  • a list of numbers or ranges: 1-4,6,8-10

Ranges have a default step value of 1, which can be adjusted using a /:

  • 1-6/2 is the same as 1,3,5
  • */3 is the same as 1,4,7,10 (month column)

Examples

$cron->set('Job1','App->job1','* * * * *'); // runs every minute
$cron->set('Job2','App->job2','*/5 * * * *'); // runs every 5 minutes
$cron->set('Job3','App->job3','0 8 * * 1'); // runs every Monday at 08:00
$cron->set('Job4','App->job4','0 4 10 * *'); // runs the 10th of each month at 04:00
$cron->set('Job5','App->job5','0 0 * */3 *'); // runs on a quarterly basis

Presets

For easier reading, it is possible to define presets:

$cron->preset('weekend','0 8 * * 6'); // runs every Saturday at 08:00
$cron->preset('lunch','0 12 * * *'); // runs every day at 12:00
$cron->set('Job6','App->job6','@weekend');
$cron->set('Job7','App->job7','@lunch');

The following presets are defined by default:

  • @yearly or @annually <=> 0 0 1 1 *
  • @monthly <=> 0 0 1 * *
  • @weekly <=> 0 0 * * 0
  • @daily <=> 0 0 * * *
  • @hourly <=> 0 * * * *

Options

Logging

If you set $cron->log=TRUE, every successfully executed job will be logged in a cron.log file located in the LOGS folder.

Web interface

By default, the routes GET /cron and GET cron/@job are available in CLI mode only, which means that an HTTP request to them will throw a 404 error.

You can enable web routes by setting $cron->web=TRUE.

In that case, /cron can be triggered via HTTP on a periodic basis, for example by your web app, or by a web cron service, or even by your own crontab:

* * * * * curl http://mydomain.tld/cron

Script path

By default, the script called asynchronously is index.php located in the current working directory.

You may need to tweak this value if:

  • your web root differs from your app root (e.g: index.php resides in www/ and starts with chdir('..'))
  • all your scheduling is handled in a separate file (e.g: cron.php instead of index.php)

Examples:

$cron->script='htdocs/index.php';//relative to app root
$cron->script=__DIR__.'/cron.php';//absolute path

PHP binary path

By default, the PHP binary used to trigger asynchronous job executions is either php or php-cli (smart guess).

You may need to tweak this value if none of these values correspond to an executable PHP CLI binary or if they are not in the path.

Example:

$cron->binary('/home/myphp-cli');

Ini configuration

Configuration is possible from within an .ini file, using the CRON variable. E.g:

[CRON]
log = TRUE
web = FALSE
script = cron.php

[CRON.presets]
lunch = 0 12 * * *

[CRON.jobs]
Job1 = App->job1, * * * * *
Job2 = App->job2, @lunch
Job3 = App->job3, @hourly

IMPORTANT: Don't forget to instantiate the class before running your app:

//index.php
$f3=require('lib/base.php')
$f3->config('cron.ini');
Cron::instance(); // <--- MANDATORY
$f3->run();

Asynchronicity

If you want tasks to be run asynchronously, you'll need:

  • exec() to be enabled on your hosting
  • the script path to be configured correctly
  • the PHP CLI binary to be executable and in the path of your hosting user

NB1: The plugin will detect automatically if jobs can be run asynchronously. If not, jobs will be executed synchronously, which may take longer and add a risk of queue loss in case of a job failure.

NB2: Asynchronicity is not available on Windows at the moment. File an issue if you need it.

UNIX user permissions

If one of your cron jobs writes data to disk, you may face some permission issues if both the cron user and the web server user try to write data to the same files.

For example, let's imagine that you cron job is executed as root and renders a HTML template to embed it in a reporting email. Then the next time the web server will try to recompile this template, it will not be allowed to modify the temporary file located in $f3->TEMP and the web user will face a 500 error.

See this issue for another example.

Here are two different ways to fix that kind of issue:

  • make sure your cron jobs are executed by the web server user, with crontab -u www mycrontab (where www is the name of the web server user)
  • make sure the web server user and the cron user belong to the same UNIX group and give group write access to the writeable folders (e.g chmod -R g+w /srv/www/tmp)

API

$cron = Cron::instance();

log

Logging of successfully executed jobs (default=FALSE)

$cron->log=TRUE;// enable logging

web

Web interface (default=FALSE)

$cron->web=TRUE;// enable web interface

script

Path of the script to call asynchronously (default='index.php')

Defaults to index.php in the current working directory.

$cron->script='htdocs/index.php';//relative to app root
$cron->script=__DIR__.'/cron.php';//absolute path

clipath

Alias for script [deprecated]

binary

Path of the PHP CLI binary (default='php' or 'php-cli')

echo $cron->binary;// php

binary( $path )

Set PHP CLI binary path

$cron->binary('/home/myphp-cli');

silent

Silent mode (default=TRUE)

Disable silent mode if you want the script to output the list of executed jobs.

$cron->silent=FALSE;

set( $job, $handler, $expr )

Schedule a job

$cron->set('Job1','App->job1','@daily'); // runs daily
$cron->set('Job2','App->job2','*/5 * * * *'); // runs every 5 minutes
$cron->set('Job3','App->job3','0 8 * * 1'); // runs every Monday at 08:00

NB: Valid characters for job names are alphanumeric characters and hyphens.

preset( $name, $expr )

Define a schedule preset

$cron->preset('weekend','0 8 * * 6'); // runs every Saturday at 08:00
$cron->preset('lunch','0 12 * * *'); // runs every day at 12:00

NB: Valid characters for job names are alphanumeric characters.

isDue( $job, $time )

Returns TRUE if the requested job is due at the given time

$cron->isDue('Job3',time()); // returns TRUE if Job3 is due now

execute( $job, $async=TRUE )

Execute a job

$cron->execute('Job2',FALSE); // executes Job2 synchronously

run( $time=NULL, $async=TRUE )

Run scheduler, i.e executes all due jobs at a given time

$cron->run(strtotime('yesterday midnight'));
// run asynchronously all jobs due yesterday at midnight

Potential improvements

  • Enable asynchronous execution on Windows.