Designing and Managing Behavior Models - Performing Actions Conditionally
(Action Router) - Creating an Action Router Rule - Defining a Rule Condition -
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Defining a Rule Condition

Defining a rule condition is one part of defining an Action Router rule. After defining the rule condition, you must define a rule action to complete the Action Router rule. For information on defining a rule action, see the section Defining a Rule Action.

 
  To define a rule condition:

1. From the client's Admin menu, choose Action Router Rule List.

   The Action Router Rule List window is displayed.

2. Select the New button in the Action Router Rule List window.

   The Action Router Rule Definition window is displayed.

   Action Router Rule Definition Window

   

   Click the thumbnail above to view full-sized image.

3. Enter a unique name for your Action Router rule in the Name field.

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   Note    The maximum length for Action Router rule names is 255 characters.

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4. Write your rule condition in the Rule Condition text area.

   You write this rule condition using Perl. However, you need not write a complete Perl statement. You can assume the following context:

   
      if (...) {
ruleAction;
}

   All you must supply is the condition that would fit inside the parentheses. For example, $OriginStateSev eq "Normal" is a complete rule condition.

   To help you write rule conditions, NerveCenter provides several aids:

   • A set of variables that contain data you can use in your rule condition. We've already seen a number of these, such as $DayOfWeek, $Time, and $OriginStateSev. For a complete list of the variables available to you, see the section NerveCenter Variables.
   • A set of functions that you can use in your rule conditions. These functions enable you to determine whether a variable contains a substring, to access information in the variable bindings of a trap that caused an alarm transition, and more.

     For more information about these functions, see the section Functions for Use in Action Router Rule Conditions.

   • A pop-up menu that lists the variables and functions you can use in a rule condition and enables you to enter the name of a variable or function in the rule-condition editing area. For further information about this pop-up menu, see the section Using the Pop-Up Menu for Perl.
   • Lists of the alarms, days, nodes, properties, property groups, severities, and triggers that you can use in a rule condition. Selecting an item from one of these list writes the name of the selected object to the rule-condition editing area.

     For further information about these lists, see the section Using Action Router's Object Lists.

Once you've finished building your rule condition, you must go to the Rule Action page and build a list of rule actions. For instructions on how to build this list, see the section Defining a Rule Action.

Functions for Use in Action Router Rule Conditions

NerveCenter provides a number of functions that you can use in your Action Router rule conditions. The list below indicates what types of functions are available and where you can find detailed information about each function:

• Variable-binding functions. These functions enable you to determine the number of variable bindings in a trigger's variable-binding list and to obtain information about each variable binding. For instance, you can retrieve the subobject and attribute associated with a variable-binding and the value of a variable-binding.

  For reference information about these functions, see the section Variable-Binding Functions.

• String-matching functions. These functions enable you to determine whether a string contains another string or a particular word. The functions are useful in conditions that test the value of a variable or variable binding for a substring.

  For reference information about these functions, see the section String-Matching Functions.

• in(). This function determines whether one scalar value is in a set of scalar values.

  For reference information about this function, see the section in( ) Function.

• Counter(). This function returns the current value of an alarm counter. For reference information about this function, see the section Counter() Function.

Using Action Router's Object Lists

If you are writing an Action Router rule condition and need to enter the name of an alarm, you do not need to:

• Look up the name of the alarm in the Alarm Definition List window.
• Type the name of the alarm in the Rule Condition editing area.

Instead, you can select the name of the alarm from a list of alarms on the Rule Condition page. Selecting this name copies the name to the Rule Condition editing area, at the point of the cursor.

In addition to a list of alarms, the Rule Condition page provides lists of:

• Days (Days are not really NerveCenter objects.)
• Nodes
• Properties
• Property groups
• Severities
• Triggers

 
  The steps below illustrate how you could enter the rule condition $AlarmName eq `Authentication':

1. In the Rule Condition editing area enter the text $AlarmName eq using the editing area's pop-up help menu or your keyboard.
2. Select the More button on the Rule Condition page to expand the page.

   Expanded Rule Condition Page

   

   Click the thumbnail above to view full-sized image.

3. Select Alarm from the Condition Type drop-down list.

   The list to the right of the drop-down list is populated with the names of all the alarms in the NerveCenter database.

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   Note    If you were writing a different rule condition, you could have selected a different object from the drop-down list.

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4. Double-click Authentication in the Alarms list.

   This action causes the text `Authentication' to be added to the rule condition.

5. After you've defined your rule's action, select the Save button.