dee1f5c427
Pypi url changed from [1] to [2] [1] https://pypi.python.org/pypi/<package> [2] https://pypi.org/project/<package> Change-Id: I32449ab8729d33b6cfe6330d764b0756f1348f27
149 lines
3.3 KiB
ReStructuredText
149 lines
3.3 KiB
ReStructuredText
..
|
|
This work is licensed under a Creative Commons Attribution 3.0 Unported
|
|
License.
|
|
|
|
http://creativecommons.org/licenses/by/3.0/legalcode
|
|
|
|
============================
|
|
Cron-based continuous audits
|
|
============================
|
|
|
|
https://blueprints.launchpad.net/watcher/+spec/cron-based-continuous-audits
|
|
|
|
Problem description
|
|
===================
|
|
|
|
Watcher currently implements a user specified interval when running continuous
|
|
audits. This may cause some collisions when the Watcher services are down,
|
|
because the next audit time isn't stored in the database.
|
|
Using a time interval isn't a flexible or user-friendly solution, instead,
|
|
we should use an industry standard like cron syntax that provides an elastic
|
|
way to schedule and execute an audit.
|
|
|
|
Use Cases
|
|
---------
|
|
|
|
* As an administrator, I want to use cron syntax to schedule audit execute.
|
|
|
|
* As an administrator, I want be sure that Watcher will set up next time
|
|
executing of audits properly.
|
|
|
|
Proposed change
|
|
===============
|
|
|
|
Watcher API already has 'interval' property in Audit object so we can use it to
|
|
store cron like format. API is to check type of incoming interval and if it is
|
|
string type then Watcher uses `croniter`_ module to set next run time.
|
|
The second proposition is to provide persistence for current 'interval' column.
|
|
To do it, we need to properly update next_run_time since its value may be less
|
|
than current time. In this case, we may use the following algorithm:
|
|
|
|
::
|
|
|
|
delta = timedelta(seconds=
|
|
(interval - (current_time-old_next_run_time).seconds % interval))
|
|
next_run_time = current_time + delta
|
|
|
|
For example, Watcher had to run audit at 7:30 am, but services went down and we
|
|
have restored it only at 9:00 am. Using interval with 3600 value, Watcher has
|
|
to set next run time at 9:30 am.
|
|
|
|
To make this spec, we need to be sure that Watcher can store continuous jobs
|
|
and its services, which may work in HA mode, takes only tag-assigned jobs.
|
|
Blueprint background-jobs-ha takes responsibility to implement job store
|
|
mechanism.
|
|
|
|
Alternatives
|
|
------------
|
|
|
|
* Continue to use already provided interval.
|
|
|
|
* Delete continuous audits after each maintenance mode and create new ones.
|
|
|
|
Data model impact
|
|
-----------------
|
|
|
|
* Type of interval column of Audit table should be changed to string type.
|
|
|
|
* New column next_run_time has to be added to Audit table.
|
|
|
|
REST API impact
|
|
---------------
|
|
|
|
None
|
|
|
|
Security impact
|
|
---------------
|
|
|
|
None
|
|
|
|
Notifications impact
|
|
--------------------
|
|
|
|
None
|
|
|
|
Other end user impact
|
|
---------------------
|
|
|
|
None
|
|
|
|
Performance Impact
|
|
------------------
|
|
|
|
None
|
|
|
|
Other deployer impact
|
|
---------------------
|
|
|
|
None
|
|
|
|
Developer impact
|
|
----------------
|
|
|
|
None
|
|
|
|
Implementation
|
|
==============
|
|
|
|
Assignee(s)
|
|
-----------
|
|
|
|
Primary assignee:
|
|
Alexander Chadin <alexchadin>
|
|
|
|
Work Items
|
|
----------
|
|
|
|
* Add next_run_time column to Audit table.
|
|
* Use croniter module to support cron-like syntax in Watcher.
|
|
* Update python-watcherclient to support cron-like syntax.
|
|
* Add logic to calculate values for next_run_time field.
|
|
|
|
Dependencies
|
|
============
|
|
|
|
https://blueprints.launchpad.net/watcher/+spec/continuously-optimization
|
|
https://blueprints.launchpad.net/watcher/+spec/background-jobs-ha
|
|
|
|
Testing
|
|
=======
|
|
|
|
Unit tests should be updated.
|
|
|
|
Documentation Impact
|
|
====================
|
|
|
|
Update documentation to mention cron and interval.
|
|
|
|
References
|
|
==========
|
|
|
|
None
|
|
|
|
History
|
|
=======
|
|
|
|
None
|
|
|
|
.. _croniter: https://pypi.org/project/croniter
|