Odoo makes running a background job easy: simply insert a record to ir.cron table and Odoo will execute it as defined.
The ir.cron table is defined in openerp/addons/base/ir/ir_cron.py file. It has the following columns:
name: a name for your cron job.
user_id: the user account id for this job. It is many2one reference to an id of the res.user table.
Be default, it is the uid that insert the data into ir.cron table. Usually it is the Administrator account.
You can set to Administrator account using the following syntax: <field name="user_id" ref="base.user_root" />
active: boolean value indicating whether the cron job is active or not.
interval_number: an integer number used as the value of repetition interval.
interval_type: the type of the interval number value. It should be one value for the list: 'minutes', 'hours','days', 'weeks', 'months'.
The default value is 'months'.
numbercall: an integer value specifying how many times the job is executed. A negative value means no limit.
doall: a boolean value indicating whether missed occurrences should be executed when the server restarts.
model: the model name of cron job method.
function: the method name of the model that is called when job is executed.
args: the arguments to be passed to the method. The string will be converted using eval('tuple(%s)' % (s or '')) and the result is passed to the job.
priority: an integer number specifying the priority of the job. 0 is the highest and 10 means lower priority. The default is 5.
Below is a sample cron job record:
<?xml version="1.0" encoding="UTF-8"?>
<!-- Cron job for Amazon synchronization -->
<record forcecreate="True" id="ir_cron_amazon_sync" model="ir.cron">
<field name="name">Amazon Integration</field>
<field eval="True" name="active" />
<field name="user_id" ref="base.user_root" />
<field eval="False" name="doall" />
<field eval="'amazon.integrator'" name="model" />
<field eval="'synchronize_cron'" name="function" />
<field eval="'()'" name="args" />
In the above definition, in every 10 minutes, it asks Odoo to call synchronize_cron method defined in amazon_integrator model.
The user is administrator. It is active and runs forever.
The "model", "function" and "args" have string defined in eval.
The synchronize_cron method should have at least three parameter as shown here: def synchronize_cron(self, cr, uid, context=None):.
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