Trac task scheduler, recurring tasks

Notice: This plugin is unmaintained and available for adoption.


This plugin adds a scheduler inside the Trac process that can handle any task written in the Python language. It allows you to have any function of a Trac related process to be added as a job.

Key features:

  • Tasks are implemented as Python plugins
  • Comes bundled with out-of-the-box tasks
  • Scheduler is implemented as a plugin
  • Bundled out-of-the-box scheduler; new: cron syntax is supported
  • Listener mechanism allows the user to be notified of task execution
  • Bundled out-of-the-box listener; new: admin panel for listener
  • Task execution history can be viewed through an rss feed

The plugin provides an administration panel to help with scheduling:

Administration panel of Trac Cron Plugin

To add a task to the scheduler simply create in a module (.py) a class that implements the ICronTask and put it in the plugins directory. Then you can either modify your trac.ini file or use the Trac cron admin panel.

Writing a task

To implement a task you have to write a Python class that inherits ICronTask:

class ICronTask(Interface):
    Interface for component task
    def wake_up(self, *args):
        Call by the scheduler when the task need to be executed
        raise NotImplementedError
    def getId(self):
        Return the key to use in trac.ini to configure this task
        raise NotImplementedError
    def getDescription(self):
        Return the description of this task to be used in the admin panel.
        raise NotImplementedError

Let's take a look at the heartbeat task included with TracCronPlugin:

class HeartBeatTask(Component,ICronTask):
    This is a simple task for testing purpose.
    It only write a trace in log a debug level
    def wake_up(self, *args):
        if len(args) > 0:
            for arg in args:
                self.env.log.debug("Heart beat: " + arg)
            self.env.log.debug("Heart beat: boom boom !!!")
    def getId(self):
        return "heart_beat"
    def getDescription(self):
        return self.__doc__

You need to implement the interface and to put the definition of the task inside the wake_up method.

Installing a task

Since tasks are components, you just have to put the class definition of your task in a Python module in the plugins directory. You can either create a .py file and put it in the plugins directory or you can package the .py file into an egg and leave it in the plugins directory.

TracCronPlugin will show the task in the administration panel.

Other examples of how to implement recurring tasks are given below.

Bugs/Feature Requests

Existing bugs and feature requests for TracCronPlugin are here.

If you have any issues, create a new ticket.


12 / 15


18 / 18


5 / 5


Download the zipped source from here. The current stable release is 0.3.1.

The plugin is also available on PyPI.


You can check out TracCronPlugin from here using Subversion, or browse the source with Trac.


You can use pip install to download and install the latest package into your Python environment:

$ pip install TracCronPlugin


The plugin can be entirely configured from either within the trac.ini file or from the administration panel. The section name of TracCronPlugin is traccron, here is a full sample:

ticker_enabled = True
ticker_interval = 1
heart_beat.daily = 21h19, 21h20
heart_beat.daily.enabled = True
hear_beat_daily.arg = Good Morging
heart_beat.enabled = True
heart_beat.hourly = 17, 18
heart_beat.hourly.enabled = False
heart_beat.monthly = 15@21h15, 15@21h16
heart_beat.monthly.enabled = False
heart_beat.weekly = 4@21h28, 4@21h29
heart_beat.weekly.enabled = False

Global settings

This controls the object called ticker, which is the thread that launches tasks. If False, no ticket (no thread) is created, so your Trac behaves like there is no cron installed. This is the global setting you can act on to enable or disable all tasks. Default value is True:

ticker_enabled = True

This key controls the interval between each wake up of the ticker. The ticker thread periodically wakes up to see if there is a task to execute. Then the ticker thread goes to sleep for the amount of minutes specified by this key. You should not have to modify this value, except if you have system load issues. Default value is 1:

ticker_interval = 1

Task settings

For each task loaded by the Trac Component manager, Trac Cron Plugin has those parameters. Let's look at a heart beat task.

Enabling and disabling a task

This is the second way to enable or disable a task. Since ticker_enabled is global and so all tasks will be affected, this key only affects one task. If False, whatever schedule the task has, none will be triggered. So this is a way to disable a task, while keeping the schedule in place for the time you will enable the task. Default is True:

heart_beat.enabled = True

Task scheduling

This controls the daily scheduler. As the name suggests, it triggers the task every day. Provide the time you want the task to execute. You can give a comma separated list to trigger the task at multiple times everyday. Default is no value:

heart_beat.daily = 21h19, 21h20

The goal of this scheduler is to trigger the task every hour. Provide the minute when you want the task to be executed. Accepts comma separated values. Default is no value:

heart_beat.hourly = 17, 18

This scheduler triggers a task that needs to be executed once a month. Provide the day in month and the hour when the task will be launched. The day is the index of the day starting at 1. Accepts comma separated values. Default is no value:

heart_beat.monthly = 15@21h15, 15@21h16

This scheduler triggers a task that needs to be executed once a week. Provide the day in week and the hour when the task will be launched. The day is the index of the day starting at 0 (Monday is 0). Accepts comma separated values. Default is no value:

heart_beat.weekly = 4@21h28, 4@21h29

Enabling and disabling a schedule

Each schedule can individually be enabled or disabled. This the configuration for the daily scheduler:

heart_beat.daily.enabled = True

This enables or disables the trigger. If False, the scheduler will not trigger the task. Default is True.

Pass argument to a task

You can pass arguments to the task on a per schedule basis. Here an example for a daily schedule:

hear_beat_daily.arg = Good Morning

When the daily schedule triggers the task, the value of the key is passed to the wake_up call. Parameters can be comma separated values. Default is empty.

Bundled Task

Besides the HeartBeat task provided for testing purposes, TracCronPlugin comes with the following useful tasks.


This task reminds the reporter about orphaned tickets and the assigned user about sleeping tickets.

  • An orphaned ticket is a ticket with status New for more than a given amount of days. An email notification is sent to the reporter in such a case.
  • A sleeping ticket is a ticket assigned to a user, but the user either did not accept it or did not touch the ticket (added a comment for example) for more than a given amount of days. The assigned user is notified in such a case.

The delay is an optional parameter associated with each schedule. Default value is 3 days.

unreachable milestone

Note: Since 0.2dev_r9388

This task scans still opened tickets in near milestone. Such a situation means that those tickets will probably not be part of the milestone. The task sends an email to the user defined with unreachable_milestone.recipient (default is empty) for each milestone with the list of still opened tickets. You may want to set the value to the release manager user. Reporter and owner are notified too, but only for their tickets. The task looks for the nearest milestone until 3 days ahead. You can change the value with parameter either by setting unreachable_milestone.<schedule>.arg or in the admin panel.

This is an example of the mail for release manager:


The milestone milestone1 is near to be closed. Its due date is 11-30-2010.

Unfortunately we have detected some open tickets.
Please consider to postpone them or ensure they will meet the milestone due date.

These ticket are:

testing ticket

testing ticket

Best regards.

My Project <http://localhost:8000/dummy>
My example project

Auto postpone task

Note: since 0.2dev_r9390.

Trac allows the administrator to postpone still opened tickets in a given milestone when he closes this milestone. But this is not mandatory. The auto postpone task will help to not forget opened tickets in a closed milestone. The task looks for such tickets and postpones them in the more recent still opened milestone. Milestone must have a due date.

Ticket deadline task

Note: since 0.3.

This task notifies to the ticket's reporter and owner when its ticket is near the deadline as a custom field. You can add a date field for ticket using the DateFieldPlugin. Besides scheduler settings, there are the following options to configure when the DateFieldPlugin is used:

  • days_before: notify days before the deadline
  • date_field: ticket custom field's name
  • date_format: this format string is handled by datetime module

Ticket with due date

Here is a sample configuration for the trac.ini file:

ticker_enabled = True
ticker_interval = 1
ticket_deadline.cron = * 0 10 * * ? * 
ticket_deadline.cron.enabled = True
ticket_deadline.enabled = True

due_date = text = true
due_date.label = Due Date
due_date.value = YYYY-MM-DD
due_date.date_empty = true

format = ymd 
separator = -
first_day = 1

Bundled Scheduler

Hourly scheduler

See task scheduling section.

Daily scheduler

See task scheduling section.

Weekly scheduler

See task scheduling section.

Monthly scheduler

See task scheduling section.

Cron Scheduler

Since 0.2dev_r9375 there is a cron scheduler. You can use cron syntax to define the schedule. Currently you can use:

  • single value
  • range value both with - or / special character
  • special value *

Example with heart_beat task:

heart_beat.cron = * 0/2 * * * ? *

Warning: since TracCronPlugin ticker interval is at least one minute, this means the seconds cannot be specified and so the first item of the cron expression is useless.

The cron like expression is here. Set either day-of-month or day-of-week and the other one must be '?':

ex: *  *  *  ?  *  ?  *
    ┬  ┬  ┬  ┬  ┬  ┬  ┬
    │  │  │  │  │  │  └──── year (omissible)
    │  │  │  │  │  └─────── day of week (1 - 7, 1 is Monday)
    │  │  │  │  └────────── month (1 - 12)
    │  │  │  └───────────── day of month (1 - 31)
    │  │  └──────────────── hour (0 - 23)
    │  └─────────────────── min (0 - 59)
    └────────────────────── None (reserved?)

Please refer to cron documentation for more details on the standard cron syntax.

Bundled Listener

Email notification of task event

This listener notifies by email about task execution. You can choose the number of event sent by email by setting the value of email_task_event.limit. When the listener has received at least the number of task execution, it will send the email. Default is 1. The value of email_task_event.recipient must be filled, otherwise no email will be sent.

Here is the configuration for this listener:

email_task_event.enabled = True
email_task_event.limit = 1
email_task_event.recipient = admin

Here an sample of the email :

The above task has been run by Trac Cron Plugin

started at 0 h 47
ended at 0 h 47

started at 0 h 48
ended at 0 h 48

started at 0 h 49
ended at 0 h 49

Since 0.2dev_r9385 you can use email_task_event.only_error = True to send email only on error.

Recent Changes

17943 by rjollos on 2020-12-23 23:45:57
Drop latest code from PyPI
15468 by rjollos on 2016-04-14 00:01:45
Remove tag_svn_revision attribute

The attribute isn't supported in setuptools >= 10

12591 by t2y on 2013-02-04 08:50:52
added TracCronPlugin-0.2 version


Author: tbressure
Maintainer: none (needsadoption)

Last modified 2 years ago Last modified on Apr 13, 2022, 6:47:28 AM

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