Plone/Zope time based event mechanism
Project description
Overview
collective.timedevents fires clock based Zope 3 events. They can make Zope application react to timers. This is useful for creating services where something must happen regurlarly or after a certain period has expired.
This is a developer level product. This product is indended to replace Products.TickingMachine with more robust Zope 3 codebase.
There are two different styles of using it:
Using the ITickEvent and calculating if action needs to be done in the event subscriber. This will also take care of timing over zope restarts by keeping event timing persistent.
Subscribing to any of the cron-style IIntervalTicks*-events, not worrying about the timing client side. For the longer ticks (weekly, montly) a cron-job as trigger makes most sense, in case of zope restarts.
Tested by Travis:
Installation
Add collective.timedevents to your buildout by adding the egg to your buildout.cfg:
eggs = ... collective.timedevents
Trigger
Can either be cron-jobs or zope clock-server.
Add clock server to tick timedevents subscribers - use your Plone instance name:
[instance] ... zope-conf-additional = <clock-server> method /mysite/@@tick period 90 user clockserver-user password password host localhost </clock-server>
Or for the cron-like interval-based events, here 900 seconds for the 15-minute event:
<clock-server> method /mysite/@@tick_fifteen period 900 user clockserver-user password password host localhost </clock-server>
Now you should start to see ticks in the zope event log.
Usage
Subscribe to the events/ticks you need.
Using the ITickEvent method:
Add collective.timedevents.interfaces.ITickEvent subscribers to your product ZCML declarations:
<configure xmlns="http://namespaces.zope.org/zope" xmlns:browser="http://namespaces.zope.org/browser" i18n_domain="harvinaiset.app"> <subscriber handler="myproduct.tickers.on_tick" for="collective.timedevents.intefaces.ITickEvent" /> </configure>Configure your event handler to react after certain period has expired:
from zope.app.component.hooks import getSite def on_tick(event): """ Do something after one hour has elapsed """ interval_in_days = 1.0 / 24.0 # One hour, floating point context = site.my_magic_context # Persistent object which stores our timing data if event.last_tick > context.last_action + interval_in_days: # Check whether enough time has elaped do_stuff() context.last_action = event.last_tick # Store when we last time did something
Using the IIntervalTicks*-events:
Add collective.timedevents.interfaces.IIntervalTicks* subscribers to your module ZCML declarations:
<configure xmlns="http://namespaces.zope.org/zope" xmlns:browser="http://namespaces.zope.org/browser" i18n_domain="mymodule"> <subscriber handler="myproduct.tickers.on_tick_fifteen" for="collective.timedevents.intefaces.IIntervalTicks15Event" /> </configure>
Other
All ticking code is executed under admin privileges.
ITickEvent tick period is 300 seconds by default. This can be controlled in views.py.
Ticks for ITickEvent are logged by events.tick_logger defined in configure.zcml.
Quality assurance
This product fills the following quality criteria:
Unit tests provided
Good documentation provided
Commented code
PyPi eggs provided
Project details
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