a. Definition – Analysis provide the majority of the functionality in VA2. An analysis rule is a scripted program that returns true or false. If true, the analysis rule does nothing, if it returns false, an error event associated with the analysis rule is fired. Analysis Rules are written in Perl, and are executed on the Central Server. Analysis rules are user definable, the only requirement is that they set the special variable $retval to a true or false value. They can be imported and exported in XML format. Analysis rules must be executable in Perl within 5 seconds, or they will be marked as inactive. Analysis rules can be set to different execution intervals. Some analysis rules you may want to run as often as possible – up to every minute. Others are may need only to be checked every week. The more analysis rules that are set to a smaller interval, the greater the burden on the host system will be.
b. Properties
i. Name – User defined name
ii. Description – User defined description of the analysis rule
iii. Type – Currently Perl is the only supported analysis rule type. Required.
iv. Execution Interval – Choose a period for an Analysis Rule from 1 minute to 1 week. The time that passes between intervals should be accurate to one second of the last run execution.
v. Active – Only active Analysis Rules will be executed. Rules are set to Inactive by the system if they have an execution error, including syntax problems or exceeding the execution interval.
vi. Rule Definition – Text Area where the Analysis Rule is defined. See appendix A, analysis rule definition guide, for the rules and conventions of writing analysis rules.
vii.
Error – The Error field is filled out when an error
occurs executing the analysis rule. When
a user corrects the error, and clicks the
Active flag on the analysis rule, the Error field filled out by the system is
removed.
viii. Launch Debugger – This option executes the debugger.exe. debugger.exe should reside in the path pointed to by the Virtual Administrator option – Edit System Settings > System Variables > Install Path. If there is no debugger.exe in that install path on the machine which the button is clicked, the debugger can not be used. Since the install path variable is also used to point to the lib directory for the Central Server, most users find it most convenient to only debug analysis rules and statistics on the same machine that Central Server is installed on. See appendix C, debugger options, for more information about using the debugger.
c. Menus
i. Add – Creates new Analysis Rule
ii. Import – Opens dialog box to browse for an Analysis Rule defined in XML format.
iii. Export – Selected analysis rule will be exported to a XML file. Multiple analysis rules can be selected for export by pressing shift or ctrl.
d. Error Definitions for Analysis Rules
i. Error definitions are associated with an analysis rule. When an analysis rule returns false, it will add an Error Event that matches the Error Definition associated with it. Analysis rules can also be scripted to over ride the error definition properties. See Appendix A for details on how to override Error Definitions associated with Analysis Rules.