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Notification templates

Extension functions and variables for cloud service events

You can use preset alert variables in notification templates. This topic describes the structure and parameters of preset alert variables for cloud service events.

Extension functions

Notification templates support Go Template built-in functions and extension functions. The following table provides the details.

Function	Description
Go Template built-in functions	Notification templates support Go Template built-in functions. For details, see the official documentation.
translate	Translate the variable value into natural language. translate(type string, lang string, val string) string type: Variable name Alert templates: Support the Region, Type, Level, and Namespace variables. Event templates: Support the Region, Type, Level, Source, and Event variables. Lang: The target language of conversion. Supported languages include zh (Chinese) and en (English). val: Variable value.
Integer calculation functions	Sum: add(i ...interface{}) int64 Subtraction: sub(a, b interface{}) int64 Maximum: max(a interface{}, i ...interface{}) int64 Minimum: min(a interface{}, i ...interface{}) int64
Collection operation functions	Slicing slice(list interface{}, indices ...int) interface{} map get(m map[string]interface{}, key string) interface{}
String functions	Truncate a string: trunc(c int, s string) string Get a substr: substr(start int, end int, s string) string Trim whitespaces: trim(s string) string Check whether a substr is present: contains(substr string, str string) bool Check whether a prefix is present: hasPrefix(substr string, str string) bool Check whether a suffix is present: hasSuffix(substr string, str string) bool Escape a string: quote(str ...interface{}) string Join strings: join(sep string, v interface{}) string Replace characters: replace(old string, new string, src string) string Format as a string: toString(v interface{}) string
Time functions	If the variable is of type time.Time, you can use the time function .Format to define the time format. For example, {{ .HappenedAt.Format "2006-01-02 15:04:05(UTCZ07:00)" }}.
JSON operations	JSON: toJson(v interface{}) string PrettyJSON: toPrettyJson(v interface{}) string

Data structure

This topic uses the following JSON example to demonstrate the variables, parameters, and data structures supported by cloud service event templates. This helps you understand common Go template syntax and its usage.

Variable description

Description

You can use the standard Go Template approach to get values of non-nested variables. For example, you can use {{ .Region }}.

For nested variables, you need to use custom variables to obtain all resources. For example, you define the $rule variable and use iteration to get all resources: {{ range $idx, $rule := .Rules }}. For internal variables, you need to use $rule.fieldName (for example, {{ $rule.RuleId }}) to get variable values.

The following table provides the parameters and descriptions of preset variables that can be used in a notification template.

Variable name	Type	Description	Sample value	Example
Type	String	Alert type. The value is Event.	Event	Render it directly: {{ .Type }} Use the extension function to translate it into natural language: {{ translate "Type" "zh" .Type }}. For example, render Event as event.
SiteName	String	Site name.	Cloud Monitor	{{ .SiteName }}
AccountName	String	Account name.	user-demo	{{ .AccountName }}
AccountId	String	Account ID.	21000*****	{{ .AccountId }}
Source	String	Event source.	ecs	Render it directly: {{ .Source }} Use the extension function to translate it into natural language: {{ translate "Source" "zh" .Source }}. For example, render ecs as Elastic Compute Service.
Level	String	Event level. Possible values: critical warning notice tip If multiple rules are matched, the highest level is applied.	critical	Render it directly: {{ .Level }} Use the extension function to translate into natural language: {{ translate "Level" "zh" .Level }}. For example, render critical as Serious.
Id	String	Event ID.	1803******	{{ .Id }}
Event	String	Event type.	ecs:Instance:RebootInstance.Executing	Render it directly: {{ .Event }} Translate into natural language: {{ translate "Event" "zh" .Event }}. For example, render ecs:Instance:RebootInstance.Executing as Instance restart: Executing.
HappenedAt	time.Time	The time when the event occurs.	2025-01-01 00:00:00(UTC+08:00)	Format the time: {{ .HappenedAt.Format "2006-01-02 15:04:05(UTCZ07:00)" }}
Region	String	Region of the cloud product resource.	cn-beijing	Render it directly: {{ .Region }} Use the extension function to translate into natural language: {{ translate "Region" "zh" .Region }}. For example, render cn-beijing as China (Beijing).
ResourceId	String	Cloud product resource ID.	i-yd9j*****	{{ .ResourceId }}
ResourceName	String	Cloud product resource name.	ecs-demo	{{ .ResourceName }}
ProjectName	String	Name of the project to which the cloud product resource belongs.	default	{{ .Project }}
TagSet	Array of Tag	Cloud product resource tags. Each tag consists of a Key and Value.	-	Iterate through tags: {{ range $idx, $tag := .Tags }} {{ $tag.Key }}: {{ $tag.Value }} {{ end }}
Details	map[string]interface{}	Event details. tip Event formats vary across different cloud products.	-	Iterate through details: {{ range $key, $val := .Details }} {{ $key }}: {{ $val }} {{ end }}
Rules	Array of EventRule	A list of matched event rules.	-	Iterate through rules: {{ range $idx, $rule := .Rules }} {{ $rule.RuleName }} ({{ $rule.Level }}) {{ end }}
HistoryURL	String	URL to the Event Center.	https://console.volcengine.com/observe/cloud-monitor/alert/history	{{ .HistoryURL }}

EventRule

Variable name	Type	Description	Sample value	Example
RuleId	String	Event rule ID.	19251****	{{ $rule.RuleId }}
RuleName	String	Event rule name.	event-demo	{{ $rule.RuleName }}
Level	String	Event rule level. Possible values: critical warning notice	critical	Render it directly: {{ $rule.Level }} Use the extension function to translate into natural language: {{ translate "Level" "zh" $rule.Level }}. For example, render critical as Serious.
RuleURL	String	URL to the event rule.	https://console.volcengine.com/observe/cloud-monitor/event/rules/detail?id=1790****	{{ $rule.RuleURL }}

Configuration example

In addition to the preset event templates, you can specify custom content of a notification template based on the data structures of alert variables, Go Template syntax, and Markdown syntax. This section provides a configuration example.

Last updated: 2026.09.07 19:40:07