Event Handler Database File

Owned by
Stonebranch
Jan 31, 2024
4 min read

Overview

Event handlers are stored in the database file uemh.db.

This page describes the parameters that comprise a record in the event handler file.

Event Handler Record

For Universal Event Monitor, an event handler represents the action that should be taken in response to a monitored event.

An event handler record consists of parameters that:

  • Describe the action to take.
  • Establish an execution environment for the action.
  • Define success or failure criteria for the action's outcome.

UEM Server executes the specified action on behalf of the event handler. Accordingly, the action also can be referred to as the event handler process.

Event Handler Parameters

The following table describes the event handler parameters.

The parameters that make up the record's key are underlined.

Parameter

Description

Remarks

Handler ID

Unique identifier for the event handler.

Length of the handler ID cannot be greater than 32 characters.
 
Value is case-sensitive.

Handler Type

Type of action that will be executed.

If the Handler Actions field contains a system command or other command line application, this field has a value of cmd.
 
If the Handler Actions field contains a series of system commands that should be executed as a script file, this field has a value of script.

Script Type

Script interpreter to invoke to execute script statements contained in the Handler Actions parameter.

On Windows-based systems, this value will be used as a file extension for the temporary script constructed by UEM Server in order to execute the script statements specified in the Handler Actions parameter. To insure proper execution of the script, a file association should exist on the target system that specifies the application with which the script should be executed.
 
This parameter is ignored:

  • On UNIX-based systems.
  • If the Handler Type has a value of cmd.

Maximum Acceptable Return Code

Highest value that the handler process can return to still be considered as having executed successfully.

If the value returned by the action is less than or equal to the value specified by this parameter, UEM will report a successful completion of the handler process.
 
If the value returned by the action is greater than the value specified by this parameter, UEM will report a failure of the handler process.

User ID

ID of the user account in whose security context the handler actions will be run.

If the UEM Server processing this record is configured to run without security, the value in this parameter is ignored.

Password

Password of the user account specified in the User ID parameter.

If the UEM Server processing this record is configured to run without security, this parameter is ignored.
 
On UNIX-based systems, a UACL entry can be defined that permits handler execution for some user accounts without requiring authentication. In such a situation, this parameter is ignored.
 
This parameter is encrypted prior to being stored in the database.

Encrypted File

Complete path to a file encrypted with Universal Encrypt.
 
The userid and password options can be stored in an external file instead of specifying the handler userid and password parameters. UEM reads the contents of this file to obtain the User ID and Password of a user account, which then is used to establish a security context in which the event handler process is executed.
 
If an encryption key was used other than Uencrypt's default, that key can be specified with the Encrypted Key parameter.

A password may not be necessary on UNIX, depending on the existing EVENT_HANDLER_ACL entries.
 
Storing the path to an encrypted file allows the file to be shared between Universal Agent applications. This makes it unnecessary to update individual event handler records whenever account information is updated or security requirements change.

Encrypted Key

Optional encryption key used to decrypt the encrypted file.

This must be the same key that was used to encrypt the file.

Handler Actions

Command or script executed by UEM Server for this handler.

For records with a Handler Type of cmd, this parameter contains the syntax required to execute a system command or other command line application.
 
For records with a Handler Type of script, this parameter contains one or more system commands that are executed collectively as a batch script.

Last Update Date/Time

Date and time that the event handler was created or last modified.

 

Last Update User

ID of the user account that created or most recently updated the event handler.

 

Options

String with one or more parameters that UEM adds to the command line that it constructs in order to execute a specified command or script.

This parameter serves the same purpose as the event definition's Handler Options parameter, but differs in scope.
 
An event definition's Handler Options are applied to every handler process executed on its behalf. An event definition's Handler Options may specify global handler execution options (for example, output redirection) or may customize event handler behavior for that specific event.
 
On the other hand, an event handler's Options value is applied every time the handler is executed, regardless of which event definition causes it to execute.
 
When command line options are specified in the event definition (via Handler Options) and in the event handler (via Options), both are used. However, the event handler's Options value is added first.