AlertingAlerting fundamentalsAnnotations and labels for alerting rulesTemplate functions

Template Functions

Template functions allow you to process alert evaluation results to generate dynamic notifications.

NameArgument typeReturn typeDescription
humanizenumber or stringstringConverts a number to a more readable format, using metric prefixes.
humanize1024number or stringstringLike humanize, but uses 1024 as the base rather than 1000.
humanizeDurationnumber or stringstringConverts a duration in seconds to a more readable format.
humanizePercentagenumber or stringstringConverts a ratio value to a fraction of 100.
humanizeTimestampnumber or stringstringConverts a Unix timestamp in seconds to a more readable format.
titlestringstringstrings.Title, capitalises first character of each word.
toUpperstringstringstrings.ToUpper, converts all characters to upper case.
toLowerstringstringstrings.ToLower, converts all characters to lower case.
matchpattern, textbooleanregexp.MatchString Tests for a unanchored regexp match.
reReplaceAllpattern, replacement, textstringRegexp.ReplaceAllString Regexp substitution, unanchored.
graphLinkstring - JSON Object with "expr" and "datasource" fieldsstringReturns the path to graphical view in Explore for the given expression and data source.
tableLinkstring- JSON Object with "expr" and "datasource" fieldsstringReturns the path to tabular view in Explore for the given expression and data source.
args[]interface{}map[string]interface{}Converts a list of objects to a map with keys, for example, arg0, arg1. Use this function to pass multiple arguments to templates.
externalURLnothingstringReturns a string representing the external URL.
pathPrefixnothingstringReturns the path of the external URL.



Template string { humanize $value }

Input 1234567.0

Expected 1.235M


TemplateString { humanize1024 $value }

Input 1048576.0

Expected 1Mi


TemplateString { humanizeDuration $value }

Input 899.99

Expected 14m 59s


TemplateString { humanizePercentage $value }

Input 0.1234567

Expected 12.35%


TemplateString { $value | humanizeTimestamp }

Input 1435065584.128

Expected 2015-06-23 13:19:44.128 +0000 UTC


TemplateString { $value | title }

Input aa bb CC

Expected Aa Bb Cc


TemplateString { $value | toUpper }

Input aa bb CC

Expected AA BB CC


TemplateString { $value | toLower }

Input aA bB CC

Expected aa bb cc


TemplateString { match "a+" $labels.instance }

Input aa

Expected true


TemplateString {{ reReplaceAll "localhost:(.*)" "my.domain:$1" $labels.instance }}

Input localhost:3000

Expected my.domain:3000

TemplateString {{ graphLink "{\"expr\": \"up\", \"datasource\": \"gdev-prometheus\"}" }}

Expected /explore?left=["now-1h","now","gdev-prometheus",{"datasource":"gdev-prometheus","expr":"up","instant":false,"range":true}]

TemplateString {{ tableLink "{\"expr\": \"up\", \"datasource\": \"gdev-prometheus\"}" }}

Expected /explore?left=["now-1h","now","gdev-prometheus",{"datasource":"gdev-prometheus","expr":"up","instant":true,"range":false}]


TemplateString {{define "x"}}{{.arg0}} {{.arg1}}{{end}}{{template "x" (args 1 "2")}}

Expected 1 2


TemplateString { externalURL }

Expected http://localhost/path/prefix


TemplateString { pathPrefix }

Expected /path/prefix