librenms-librenms/doc/Alerting/Templates.md

source: Alerting/Templates.md

Templates

Templates can be assigned to a single or a group of rules and can contain any kind of text. There is also a default template which is used for any rule that isn't associated with a template. This template can be found under Alert Templates page and can be edited. It also has an option revert it back to its default content.

The template-parser understands if and foreach controls and replaces certain placeholders with information gathered about the alert.

Syntax

Controls:

• if-else (Else can be omitted): {if %placeholder == value}Some Text{else}Other Text{/if}
• foreach-loop: {foreach %faults}Key: %key<br/>Value: %value{/foreach}

Placeholders:

Placeholders are special variables that if used within the template will be replaced with the relevant data, I.e:

The device %hostname has been up for %uptime seconds would result in the following The device localhost has been up for 30344 seconds.

• Hostname of the Device: %hostname
• sysName of the Device: %sysName
• location of the Device: %location
• uptime of the Device (in seconds): %uptime
• short uptime of the Device (28d 22h 30m 7s): %uptime_short
• long uptime of the Device (28 days, 22h 30m 7s): %uptime_long
• description (purpose db field) of the Device: %description
• notes of the Device: %notes
• Title for the Alert: %title
• Time Elapsed, Only available on recovery (%state == 0): %elapsed
• Alert-ID: %id
• Unique-ID: %uid
• Faults, Only available on alert (%state != 0), must be iterated in a foreach ({foreach %faults}). Holds all available information about the Fault, accessible in the format %value.Column, for example: %value.ifDescr. Special field %value.string has most Identification-information (IDs, Names, Descrs) as single string, this is the equivalent of the default used.
• State: %state
• Severity: %severity
• Rule: %rule
• Rule-Name: %name
• Timestamp: %timestamp
• Transport name: %transport
• Contacts, must be iterated in a foreach, %key holds email and %value holds name: %contacts

Placeholders can be used within the subjects for templates as well although %faults is most likely going to be worthless.

NOTE: Placeholder names which are contained within another need to be ordered correctly. As an example:

Limit: %value.sensor_limit / %value.sensor_limit_low

Should be done as:

Limit: %value.sensor_limit_low / %value.sensor_limit

The Default Template is a 'one-size-fit-all'. We highly recommend defining your own templates for your rules to include more specific information.

Examples

Default Template:

%title
Severity: %severity
{if %state == 0}Time elapsed: %elapsed{/if}
Timestamp: %timestamp
Unique-ID: %uid
Rule: {if %name}%name{else}%rule{/if}
{if %faults}Faults:
{foreach %faults}  #%key: %value.string{/foreach}{/if}
Alert sent to: {foreach %contacts}%value <%key> {/foreach}

Conditional formatting example, will display a link to the host in email or just the hostname in any other transport:

{if %transport == mail}<a href="https://my.librenms.install/device/device=%hostname/">%hostname</a>
{else}
%hostname
{/if}

Note the use of double-quotes. Single quotes (') in templates will be escaped (replaced with \') in the output and should therefore be avoided.

Included

We include a few templates for you to use, these are specific to the type of alert rules you are creating. For example if you create a rule that would alert on BGP sessions then you can assign the BGP template to this rule to provide more information.

The included templates apart from the default template are:

• BGP Sessions
• Ports
• Temperature