Cisco Cisco Process Orchestrator 3.0 Guida Utente
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Cisco Process Orchestrator User Guide
OL-30196-01
Chapter 8 Working with Events and Triggers
Correlating Events
This capability is exposed through Correlate activities. For example, the Correlate Windows Events
activity allows the correlation of related events from the Windows Event Logs.
activity allows the correlation of related events from the Windows Event Logs.
Process Orchestrator provides Correlate activities that correspond to many types of supported triggers.
Typically, if Process Orchestrator provides a trigger, it will also provide a correlation activity, though
this is not explicitly required.
Typically, if Process Orchestrator provides a trigger, it will also provide a correlation activity, though
this is not explicitly required.
Figure 8-1
A Correlate Activity
Correlate activities have several key pieces of data that specify the events to find:
•
The time window in which the event can occur
•
The number of events to match. If a number is specified, and when the process workflow execution
gets to the correlate activity that number of events has already occurred within the time window, the
Correlate activity will immediately match. If not, the activity will block waiting for those events to
occur. If all is specified, the activity will wait until the end of the window and then return the results.
gets to the correlate activity that number of events has already occurred within the time window, the
Correlate activity will immediately match. If not, the activity will block waiting for those events to
occur. If all is specified, the activity will wait until the end of the window and then return the results.
•
The event criteria. This presents fields for filtering that type of event and is specific to the event type
and adapter.
and adapter.
Events that match a Correlate activity are available to the later steps in the workflow and are published
in the automation summary.
in the automation summary.
From a technology perspective, the server implementation:
•
Allows activities to complete in real time. If you wait for one event and a matching event arrives,
the activity will complete immediately rather than waiting until the end of the time window.
the activity will complete immediately rather than waiting until the end of the time window.
•
Handles cases where event arrival might precede process execution of the correlation node. A
process might not even be executing when an event arrives; it could be triggered later and look
retrospectively for matching events. The server must cache data given its knowledge of Correlate
activities in process definitions so it is ready to provide matched events should a Correlate activity
execute later.
process might not even be executing when an event arrives; it could be triggered later and look
retrospectively for matching events. The server must cache data given its knowledge of Correlate
activities in process definitions so it is ready to provide matched events should a Correlate activity
execute later.
•
Allows that correlation activities may never run due to untriggered workflows or workflow logic
taking a different flow.
taking a different flow.