evmfilterfile(4)

NAME

evmfilterfile — Event Manager filter file

SYNOPSIS

filter {
name       filter_name
valuex     filter_value
include    filter_element
exclude    filter_element
title      filter_title
}

DESCRIPTION

A filter file contains one or more filter descriptions, which can be referenced through certain EVM commands by using indirect filter syntax. An indirect filter specifier has the following form:

@filename[:filter_name]

In the previous indirect filter specifier, filename is the name of a filter file, and filter_name is the name of a filter contained in the file. If no filter_name is specified, the first filter in the file is used.

By convention, filter file names should have the suffix .evf. If a command cannot find the file with the name as specified, it appends .evf and tries again.

If a relative pathname is given for a file, commands search for the file in each location specified by the EVM_FILTERDIR environment variable if it is present. Otherwise the search is performed in the following standard locations in turn, stopping as soon as the file is found:

The current working directory
/var/evm/adm/filters
/usr/share/evm/filters

Several supplied filter files, containing shortcut filters for many system events, can be found in the directory /usr/share/evm/filters. System administrators should place site-specific filter files in /var/evm/adm/filters.

The filter file is made up of a series of keyword/value and keyword/group pairs. Values containing spaces must be enclosed in double quotes. Strings may be continued across a newline by finishing the line with a backslash character. Any portion of a line from an unquoted number sign (#) to the end of line is a comment. Blank lines are ignored.

The following keywords are recognized:

filter: Introduces a filter group.
name filter_name: Names the filter.
value filter_value: The filter_value is a string that conforms to EVM filter syntax. See the EvmFilter(5) manpage for information about filter syntax.
include filter_element: Modifies the current filter_value. See the description of the include and exclude keywords below.
exclude filter_element: Modifies the current filter_value. See the description of the include and exclude keywords below.
title filter_title: The filter_title is a text string that describes the purpose of the filter. The title is not currently used, but always should be included.

The include and exclude keywords can appear multiple times in a filter group, allowing you to build and maintain a filter in simple single-line increments. Each filter_element must be a valid filter string, conforming to the syntax described in the EvmFilter(5) manpage. A complete filter string is assembled by surrounding the initial filter with parentheses and appending the filter_elements to it, separating each with a logical OR (for include) or AND NOT (for exclude) operator. For example:

value     "[priority >= 200]" 
include   "[name *.mylog]" 
exclude   "[name *.oldlog]" 

The previous filter lines are equivalent to this more complex single filter line:

value    "([priority >= 200]) OR [name *.mylog] AND NOT [name *.oldlog]" 

The first line selects all events with a priority of 200 or greater, the next modifies this by selecting all events from mylog regardless of their priorities, and the last line excludes all oldlog events regardless of their priorities.

If you prefer, you can omit the value command, and build the complete filter string from include and exclude lines.

Notes

If you are concerned with allowing your file to be used on other systems that support EVM in the future, you should use the built-in macro @SYS_VP@ in place of the first two components (sys.unix) of the name of any system event. This will make it unnecessary to change the file if the other system uses a different event name prefix.

EXTERNAL INFLUENCES

Environment Variables

EVM_FILTERDIR: A colon-separated set of directory pathnames to be searched for a requested filter file. If this variable is present in the environment the directories are searched in place of the standard directories.

EXAMPLES

1.

The following is an example of a pair of entries in a filter file:

# Select all events posted by myapp, excluding any that 
# have a priority lower than 200: 
filter 
{   name    myapp 
    value   "[name myco.myapp.*]" 
    exclude "[pri < 200]" 
    title   "All myapp events" 
} 

# Select all events posted by myapp, and important system events: 
filter 
{   name    sys_myapp 
    value   "[name myco.myapp.*] | \ 
                  ([name @SYS_VP@.*] & [priority >= 400])" 
    title   "System errors and myapp events" 
} 

2.

The following command finds and displays all EVM events, using a filter stored in the supplied filter file /usr/share/evm/filters/sys.evf:

evmget -f @sys:evm | evmshow 

3.

Assuming that the filter file shown in the first example is named myapp.evf and is located in a standard filter directory, the following command displays the value of the sys_myapp filter from that file:

evmshow -F -f @myapp:sys_myapp

FILES

/var/evm/adm/filters/*.evf: Site-specific filter files.
/usr/share/evm/filters/*.evf: System filter files.

evmfilterfile(4)

Technical documentation

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NAME

SYNOPSIS

DESCRIPTION

Notes

EXTERNAL INFLUENCES

Environment Variables

EXAMPLES

FILES

SEE ALSO

Commands

Routines

Event Management

EVM Events

Event Filter