Template variables #

Introduction #

When custom alerting triggers event content, in addition to the fixed copy written by yourself, the event title and event content also support template syntax. The rendering of the text can be achieved using fields in the event.

Variables #

The syntax for rendering fields is {{ .fieldname }}, and the variable fields that can be used for template content rendering are as follows:

Variable usage example #

Example 1:

{"content":"【Alerting】Event ID: {{.event_id}}, Cluster：{{.resource_name}}"}

Example 2(array traversal):

{{range .results}} Cluster ID: {{index .group_values 0}} {{end}}

Template functions #

In addition to directly displaying the field value in the alerting event, it also supports the use of template functions to further process the field value to optimize the output.

Functions support extra parameters. When no parameters are required or passed, the following syntax can be used directly:

{{ <field> | <function> }}

Specific examples are as follows:

Functions take no parameters:

Alerting event trigger time:{{ .timestamp | datetime }}

Functions take parameters:

Alerting event trigger time:{{ .timestamp | datetime_in_zone "Asia/Shanghai" }}

Use multiple functions in combination:

{{.result_value | format_bytes 2 ｜ to_upper}}

The complete list of template functions is as follows:

Common Template Syntax #

Array traversal：

{{range .results}} priority: {{.priority}} {{end}}

Get values by array subscript:

Example: group_values = [“value1”,“value2”,“value3”]

{{index .group_values 0}}
# output: value1
{{index .group_values 2}}
# output: value3

if conditional branch：

{{if pipeline}} T1 {{else}} T0 {{end}}

Example:

{{if eq .priority "critical"}} "#C91010" {{else if eq .priority "high"}} "#EB4C21" {{else}} "#FFB449" {{end}}

There is also a set of binary comparison operators defined as functions:

eq
	Returns the boolean truth of arg1 == arg2
ne
	Returns the boolean truth of arg1 != arg2
lt
	Returns the boolean truth of arg1 < arg2
le
	Returns the boolean truth of arg1 <= arg2
gt
	Returns the boolean truth of arg1 > arg2
ge
	Returns the boolean truth of arg1 >= arg2

{
    "blocks": [
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": "【test201】Alerting:\n<http://localhost:8000/#/alerting/alert/{{.event_id}}|{{.title}}> <@username>"
            }
        },
        {
            "type": "section",
            "text": {
                "type": "mrkdwn",
                "text": "*Timestamp:* {{.issue_timestamp | datetime}}"
            }
        }
    ],
    "attachments": [
        {{range .results}}
        {
            "color": {{if eq .priority "critical"}} "#C91010" {{else if eq .priority "high"}} "#EB4C21" {{else}} "#FFB449" {{end}},
            "blocks": [
                {
                    "type": "section",
                    "fields": [
                        {
                            "type": "mrkdwn",
                            "text": "*Cluster:* {{index .group_values 0}}"
                        },
                        {
                            "type": "mrkdwn",
                            "text": "*Node:* {{index .group_values 1}}"
                        },
                        {
                            "type": "mrkdwn",
                            "text": "*Threshold:* {{index .threshold 0}}"
                        },
                        {
                            "type": "mrkdwn",
                            "text": "*Priority:* {{.priority}}"
                        },
                        {
                            "type": "mrkdwn",
                            "text": "*Monitoring value:* {{.result_value}}"
                        },
                        {
                            "type": "mrkdwn",
                            "text": "*Disk usage:* {{.relation_values.a | format_bytes 2 | to_upper}}"
                        }
                    ]
                }
            ]
        },
        {{end}}
    ]
}

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