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evmtemplate(4)
NAME
evmtemplate - Event Manager template file
SYNOPSIS
event {
name event_name
format format_specifier
priority priority
i18n_catalog i18n_cat
i18n_set_id i18n_set
i18n_msg_id i18n_msg
reference reference_string
cluster_event cluster_event
var {
name variable_name
type variable_type
value variable_value
i18n_msg_id variable_value
}
}
DESCRIPTION
A template event is a description of an event that is held centrally by
EVM. The template is used for the following purposes:
· To register the event with the EVM daemon, so that it will allow the
event to be posted.
· To centralize event information. This makes it easy to review and
maintain details such as the associated message text and the event
priority, and minimizes the amount of information that must be hard-
coded into an application.
On startup, and each time the evmreload -d command is run, the EVM daemon
reads all valid event template files stored in the template directory tree
rooted at /usr/share/evm/templates, or in any directory tree linked to that
directory, including the local template tree rooted at
/var/evm/adm/templates. There is no limit to the number of template files
that can be installed in the tree, or to the number of templates that can
be included in each file.
Template file names must end with the suffix .evt, and the files must be
owned by root or bin, and must have permissions of 0400, 0600, 0440 or 0640
to be recognized. If template files are added, deleted or modified while
the daemon is running, the evmreload -d command should be used to instruct
the daemon to reconfigure itself. Refer to the evmreload(8) reference page
for more information.
Every template event must contain a name data item with at least two
components. A template typically also contains constant items such as the
event priority and the message format string.
When a client posts an event, it must include in the posted event a name
with at least three components. The posted event also typically contains
any applicable variable data along with environmental items such as a
timestamp and the name of the posting system.
When the EVM daemon receives a posted event, it searches its template
database for the template event whose name best matches the name in the
posted event. If it cannot find a matching template, the daemon rejects
the posting attempt. Otherwise, the daemon merges the data items held in
the two versions of the event, yielding a merged event which it distributes
to subscribers.
A template event name does not have to be identical to the name of a posted
event to be considered a match. If it has fewer name components than the
posted event, a template event is still considered a match if all
components in the template name exactly match their equivalent components
in the posted name. If the template name is longer than the name of the
posted event however, it cannot be a match. In determining the template
that best matches the name of the posted event, the daemon selects the
matching template with the most components.
The following table shows some examples of event name matching. In the
final example, the template does not match the posted event because the
template has too many components.
______________________________________________________________
Posted Name Template Name Match?
______________________________________________________________
myco.myprod.env myco.myprod.env Yes
myco.myprod.env Yes
myco.myprod.env.temp.high.70
myco.myotherprod myco.myprod No
myco.myotherprod myco.myotherprod.start No
______________________________________________________________
The syntax of an event template file is identical to the syntax of a file
given as input to the evmpost command. The following keywords may be
specified in a template file:
event
This keyword introduces an event group. The body of the group is
delimited by braces.
name event_name
Names the template event. The name must be made up of two or more
components containing only alphanumeric and underscore (_) characters,
and separated by dot (.) characters.
format format_specifier
Event format text. The format_specifier is a string that will be used
to produce a formatted message for display if the event is passed
through the evmshow(1) command, the sysman(8) event viewer, or the
EvmEventFormat(3) library function.
If a format_specifier contains no special characters, it is displayed
unchanged as the event's message text. For example, if evmshow
encounters an event containing the following simple format_specifier,
it displays the string exactly as specified:
EVM logger: Logger started
If the format_specifier contains variable-specifier in the form
$variable_name, and either the posted event or the template event
contains a variable with that name, the variable_value will be included
in the formatted output in place of the variable_specifier. If no such
variable is present, the variable_specifier is included in the output.
For example, if an event contains a variable called logname and the
format_specifier:
EVM logger: Started eventlog $logname
then evmshow might display the event as:
EVM logger: Started eventlog /var/evm/evmlog/evmlog.20000228
If the format_specifier contains a data-item-specifier in the form
@item_name, the data-item-specifier is replaced with the value of the
corresponding data item from the event. For example, if an event
contains a variable called message and the format_specifier is:
EVM user msg (@user_name): $message
then evmshow might display the event as:
EVM user msg (steve): Engineering group is off-site today
If the data item is not present in the event, a hyphen character (-) is
output in its place. An @ character that is not associated with a
valid item name is unchanged in the output.
Any characters in the format_specifier that are not part of a
variable_name or data-item-specifier are output unchanged.
If no format_specifier is supplied in either the template file or the
posted event, a default event message is used when the event is
formatted for display.
priority priority
Indicates the importance of the event, but does not affect the order of
event distribution. The priority must be an integer value in the range
0 (lowest) to 700. See the EvmEvent(5) reference page for the meanings
of specific priority values.
i18n_catalog i18n_cat
The name of an I18N catalog file holding text strings to be displayed
in place of the strings contained in the event. This item is used for
internationalizing events. If it is omitted, the strings contained in
the event will be used when the event is formatted for display. Refer
to the Programmer's Guide for more information.
i18n_set_id i18n_set
Identifies the message set within the i18n_cat to be used for
translation of all internationalized strings in the event. This item
is ignored if no i18n_cat is supplied.
i18n_msg_id i18n_msg
Identifies the I18N catalog message to be used in place of the format
data item when the event is formatted for display. This item is
ignored if no i18n_cat is supplied. If an i18n_set has been specified,
the i18n_msg must refer to a message identifier within the given set.
If the catalog is missing, or if the i18n_set or i18n_msg values do not
refer to a message in the catalog, the event's format data item is
used.
reference reference_string
This text string is intended to be used by an event channel's
explanation function to retrieve explanation text for the event. The
format of the string is defined by the event channel.
cluster_event cluster_event
If this Boolean value is set to TRUE, and the event is posted in a
cluster environment, the event is distributed to all members of the
cluster. The default value is FALSE.
var This keyword introduces a variable group, with the body of the group
being delimited by braces. An event may include any number of variable
groups.
Although actual variable values are most likely to be included in the
posted version of an event, and will override the values specified in
the template version, it is usually helpful to include the variables in
the template event as well, specifying dummy values such as zero, to
provide documentation of the expected contents. For example, the
template version will be seen if the results of an evmwatch -i command
are piped into evmshow -d.
The following keywords are recognized in a variable group:
name variable_name
The name must be made up of alphanumeric and underscore characters.
type variable_type
The type of the variable item. See the EvmEvent(5) reference page
for a list of types. All EVM variable types may be specified
except for OPAQUE. If this keyword is omitted a type of STRING is
assumed.
value variable_value
Value for the variable. A value must be specified in the template,
but usually should be overridden by the value in the posted version
of the event. Values supplied in the template should be default or
nonnormal values that will be recognized as incomplete when the
event is interpreted.
i18n_msg_id i18n_msg
For STRING variables, the i18n_msg identifies the I18N catalog
message to be used in place of the variable_value when the event is
formatted for display. This item is ignored if no i18n_cat is
supplied for the event. If an i18n_set has been specified, the
i18n_msg must refer to a message identifier within the given set.
If the catalog is missing, or if the i18n_set or i18n_msg values do
not refer to a message in the catalog, the variable_value is used.
Any items specified outside an event group are global items, which will be
included in each following template that does not include them explicitly.
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.
EXAMPLES
The following file is an example of an event template file.
# My example event file
priority 200
event {
name myco.myapp.env.humid
format "myapp: Humidity is $humidity"
var { name humidity type INT16 value 0 }
}
event {
name myco.myapp.env.temp.normal
format "myapp: Temperature is normal ($temp)"
var { name temp type FLOAT value 0.0 }
}
event {
name myco.myapp.env.temp.high
priority 500
format "myapp: Temperature exceeds 80F ($temp)"
var { name temp type FLOAT value 0.0 }
}
event {
name myco.myapp.env.app_terminated
priority 300
format "myapp: Production monitoring terminated - code $exit_code"
var { name exit_code type INT16 value 0 }
}
FILES
/usr/share/evm/templates
The root of the directory tree containing system event template files.
/var/evm/adm/templates
The root of the directory tree containing local event template files.
This directory is accessed from the system template directory through a
symbolic link.
SEE ALSO
Commands: evmpost(1), evmshow(1), evmd(8), sysman(8)
Routines: EvmEventCreate(3), EvmEventDump(3), EvmEventFormat(3),
EvmEventPost(3), EvmItemSet(3)
Files: evmdaemon.conf(4)
Event Management: EVM(5)
EVM Events: EvmEvent(5)
Programmer's Guide
System Administration
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