Built-in functions in alert templates

By default, if the conversion fails, the function returns 0.0. You can also specify a custom return value in the event of a conversion failure by using the default parameter.

• The result returned by {{ float("123") }} is 123.0.
• The result returned by {{ float("foo") }} is 0.0.
• The result returned by {{ float("foo", default=1.23) }} is 1.23.

By default, if the conversion fails, the function returns 0. You can also specify a custom return value in the event of a conversion failure by using the default parameter.

• The result returned by {{ int(1.23) }} is 1.
• The result returned by {{ int("1.23") }} is 1.
• The result returned by {{ int("foo") }} is 0.
• The result returned by {{ int("foo", default=5) }} is 5.

• The result returned by {{ length("foo") }} is 3.
• The result returned by {{ length([1, 2]) }} is 2.
• The result returned by {{ length({"foo": "bar"}) }} is 1.

1 indicates that one decimal place is retained.

• The result returned by {{ round(1.23) }} is 1.
• The result returned by {{ round(1.56) }} is 2.
• The result returned by {{ round(1.56, 1) }} is 1.6.

The value 1.23 is a string.

• The n variable specifies the number of characters that you want to retain in the string.
• The end variable specifies the substring that you want to add to the string after the string is truncated.

• The result returned by {{ truncate("foo bar", 5) }} is foo b.
• The result returned by {{ truncate("foo bar", 5, end="...") }} is foo b...

• The result returned by {{ quote(123) }} is "123".
• The result returned by {{ quote("foo") }} is "foo".

You can use the n parameter to specify the number of spaces with which you want to indent each line of strings.

• For {{ "foobar\n" }}{{ indent("foo\nbar") }}, the following result is returned:
  foobar
      foo
      bar

• For {{ "foobar\n" }}{{ indent("foo\nbar", 2) }}, the following result is returned:
  foobar
    foo
    bar

• You can use the sep parameter to specify the delimiter that you want to use to split a string.
• You can use the maxsplit parameter to specify the maximum number of times that a string can be split.

  If you do not configure the maxsplit parameter or if you set the maxsplit parameter to -1, the number of times that a string can be split is not limited.

• The result returned by {{ split('a b c ') }} is ['a', 'b', 'c'].
• The result returned by {{ split('a-b-c', sep='-') }} is ['a', 'b', 'c'].
• The result returned by {{ split('a-b-c', sep='-', maxsplit=1) }} is ['a', 'b-c'].
• The result returned by {{ split('a<>b<>c', sep='<>') }} is ['a', 'b', 'c'].

• The result returned by {{ list(("foo", "bar")) }} is ['foo', 'bar'].
• The result returned by {{ list("foo") }} is ['f', 'o', 'o'].

If you want to sort the elements of a list in reversed order, specify reverse=true.

• The result returned by {{ sort([3, 1, 2]) }} is [1, 2, 3].
• The result returned by {{ sort([3, 1, 2], reverse=true) }} is [3, 2, 1].

• Example on the alert.labels field:
  {
      "host": "host-1",
      "app": "nginx"
  }

• Configuration of the function in the alert template:
  {%- for key, val in dictsort(alert.labels) %}
  {{ key }}: {{ val }}
  {%- endfor %}

• Result:
  app: nginx
  host: host-1

You can use the d parameter to specify the character that is used to join the elements of the list.

• The result returned by {{ join([1, 2, 3]) }} is 123.
• The result returned by {{ join([1, 2, 3], ',') }} is 1,2,3.

• The result returned by {{ to_json("foo") }} is "foo".
• The result returned by {{ to_json(1.23) }} is 1.23.
• The result returned by {{ to_json(True) }} is true.
• The result returned by {{ to_json(alert.labels) }} is {"host": "host-1", "app": "nginx"}.

• The result returned by {{ parse_json('{"foo": "bar"}').foo }} is bar.
• The result returned by {{ parse_json('[1, 2, 3]')[1] }} is 2.

You can use the fmt parameter to specify the format of the datetime expression.

• The result returned by {{ parse_date(1629820800) }} is 2021-08-25 00:00:00.
• The result returned by {{ parse_date("2021|08|25|00|00|00", fmt="%Y|%m|%d|%H|%M|%S") }} is 2021-08-25 00:00:00.

You can use the fmt parameter to specify the format of the datetime expression.

If the input value is not a date object, the function converts the input value to a date object before the function formats the input value. For more information about the directives that are used to format date and time strings, see Date and time formatting directives. For more information about time zones, see Time zones.

• The result returned by {{ format_date(1629820800) }} is 2021-08-25 00:00:00.
• The result returned by {{ format_date(1629820800, fmt="%Y/%m/%d %H:%M:%S") }} is 2021/08/25 00:00:00.
• The result returned by {{ format_date(1629820800, tz="UTC", fmt="%Y/%m/%d %H:%M:%S") }} is 2021/08/24 16:00:00.

If the input value is not a date object, the function converts the input value to a date object before the function formats the input value.

• The result returned by {{ timestamp("2021-08-25 00:00:00") }} is 1629820800.
• The result returned by {{ timestamp(parse_date("2021-08-25 00:00:00")) }} is 1629820800.

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The result returned by {{ 10 | format_duration }} is 10s.
• The result returned by {{ 60 | format_duration }} is 1m.
• The result returned by {{ 3600 | format_duration }} is 1h.
• The result returned by {{ 86400 | format_duration }} is 1d.
• The result returned by {{ 100000 | format_duration }} is 1d3h46m40s.
• The result returned by {{ 100000 | format_duration(sep=",") }} is 1d,3h,46m,40s.

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The type of the alert is sls_pub.
• Configuration of the function in the alert template:
  {{ format_type(alert.type) }}

• Result:
  • If the value of the locale parameter is en-US, the type of the alert in the alert notification is Pub Alert.

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The region of the alert is cn-hangzhou.
• Configuration of the function in the alert template:
  {{ format_region(alert.region) }}

• Result:
  • If the value of the locale parameter is en-US, the region of the alert in the alert notification is China (Hangzhou).

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The severity level of the alert is 6
• Configuration of the function in the alert template:
  {{ format_severity(alert.severity) }}

• Result:
  • If the value of the locale parameter is en-US, the severity level of the alert in the alert notification is Medium in yellow.

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The status of the alert is Firing.
• Configuration of the function in the alert template:
  {{ format_status(alert.status) }}

• Result:
  • If the value of the locale parameter is en-US, the status of the alert in the alert notification is Firing in red.

• The following alert labels are added:
  {
      "app": "nginx",
      "host": "host-1"
  }

• Configuration of the function in the alert template:
  {{ to_list(alert.labels) }}

• Result:
  • If the alert notification is in the Markdown format, the function returns the following result:

    The function can automatically escape characters in the result based on the configuration of the notification method.

    - app: nginx
    - host: host-1

  • If the alert notification is in the HTML format, the function returns the following result:
    <ul>
      <li>app: nginx</li>
      <li>host: host-1</li>
    </ul>

  • If the alert notification is in the text format, the function returns the following result:
    [app: nginx][host: host-1]

You can use the locale parameter to specify the language in which the text description is written. For more information about the valid values of the locale parameter, see the "Valid values of the locale parameter in alert functions" section of this topic.

• The following annotations are added:
  {
      "title": "NGINX access error",
      "desc": "80% year-on-year decrease on PVs",
      "cnt": "120"
  }

• Configuration of the function in the alert template:
  {{ annotations_to_list(alert.annotations) }}

• Result:
  If the alert notification is in the Markdown format, the function returns the following result:

  -Title: NGINX access error
  -Description: 80% year-on-year decrease on PVs
  - cnt: 120

• If the alert notification is in the Markdown format, a closing angle bracket > is added to the beginning of each line.
• If the alert notification is in the HTML format, the <blockquote> tag is used to enclose the content of the alert notification.

• Configuration of the function in the alert template:
  {{ blockquote("foo\nbar") }}

• Result:
  • If the alert notification is in the Markdown format, the function returns the following result:
    > foo
    > bar

  • If the alert notification is in the HTML format, the function returns the following result:
    <blockquote>
    foo
    bar
    </blockquote>