Job controller

synopsis:

How the job-controller works

The job controller is a common job created with django-extensions to control other jobs in the system. Ideally, it should run every minute, but this isn’t mandatory and will depend on your needs.

Its run method executes the following tasks in sequence:

Remove old jobs

Remove from the jobs table those that were removed from the code. Whenever a job is removed from the code, its record in the cronjobs table is also removed, along with all execution and scheduling records.

Sync new jobs

Add in the jobs table those new jobs that were been created in the code. Whenever a new job is created in the code, a record in the cronjobs table is added to represent it in the admin interface.

Run scheduled jobs

IdentiIdentifies the jobs that are scheduled to run at this time (scheduled start is less than or equal to now) and invokes them encapsulated in a threading.Thread object to take advantage from execution parallelism.

The schedule status is changed to Running to ensure that neither the user nor another instance of the job-controller starts another job execution.

If the running job throws any exception, the error message will be captured and saved in the Jobschedule result field and the has_errors field will be set to True.

Stdout and stderr are captured and added to the Jobschedule’s result field. If there is any text in stderr, the has_errors field is set to True.

Schedule jobs

Creates scheduling records to the next execution for jobs that do not have any records with the status running or scheduled.

Digest emails

Generates log summary and send it by email.

Remove old logs

Delete old logs from database.