Cron
is a time based event generator and task execution system.
Architecturally it is useful for automatically
triggering recurring processes and single activities at a specific
future date and time.
The NetKernel Cron transport provides a singe global service which maintains a
list of Scheduled Jobs.
When the time arrives for a scheduled job to be executed the transport
makes a request for the associated URI address.
The list of scheduled jobs may be viewed and managed with the
Scheduled Job Manager available from the
Control Panel.
The transport uses a Cron Log to
record various events associated with the transport and
messages from the scheduled jobs.
Scheduled Jobs may be added to or deleted from the transport's list
with client tools (see below).
Alternatively, a module may use the
Entrypoint System
to register one or more scheduled jobs (see configuration below).
Architecture
The Cron transport runs in its own fulcrum module [install]/modules/tpt-cron/
and uses the
Quartz
open-source library.
The Cron transport is automatically started when
NetKernel starts and runs until NetKernel is shutdown.
When NetKernel and the Cron transport are shutdown normally all information
about scheduled jobs is stored for use when NetKernel and the Cron transport
are restarted.
Upon startup, the Cron transport checks to see if any persisted scheduled jobs
should have been run during the time the transport was not running.
If such scheduled jobs are found they are run immediately and a note is
made in the log.
All other scheduled jobs are brought back to life and wait until their
scheduled time to be run.
Configuration
The Cron transport itself requires no configuration.
Each scheduled jobs is configured using the following
XML based configuration.
<jobs>
<job>
<uri>ffcpl:/accounts/synchronize-payments</uri>
<name>Synchronize Accounts</name>
<desc>Synchronize account payments every night at midnight</desc>
<userJobData>
<data>
<name>currency</name>
<value>USD</value>
</data>
</userJobData>
<cron>
<expr>0 0 0 ? * *</expr>
</cron>
</job>
<job>
<uri>ffcpl:/accounts/print-checks</uri>
<name>Print Checks</name>
<desc>Print checks one minute after startup</desc>
<simple>
<startTime>60000</startTime>
<endTime />
<repeatCount>1</repeatCount>
<repeatInterval />
</simple>
</job>
</jobs>
For a detailed description of the cron element and it's
options, please refer to the
Cron Transport Guide.
Preface
Cron
GUI Events
