The new alert templates support built-in functions. You can use the built-in functions to configure the formats and styles of alert notifications. This topic describes the syntax of the built-in functions and provides examples on how to use the built-in functions.

General functions

Numeric functions

Function Description Filter Example
float(value, default=0.0) Converts an integer or a string to a floating-point number.

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.

Supported
  • 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.
int(vlaue, default=0) Converts a string or a number to an integer.

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.

Supported
  • 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.
length(value) Obtains the length or number of elements in an object such as a string, list, or tuple. Supported
  • 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.
abs(value) Obtains the absolute value of a number. Supported The result returned by {{ abs(-1) }} is 1.
min(value) Obtains the minimum value among the values that you specify. Supported The result returned by {{ min([1, 3, 2]) }} is 1.
max(value) Obtains the maximum value among the values that you specify. Supported The result returned by {{ max([1, 3, 2]) }} is 3.
ceil(value) Rounds a number up to the nearest integer. Supported The result returned by {{ ceil(1.23) }} is 2.
floor(value) Rounds a number down to the nearest integer. Supported The result returned by {{ floor(1.23) }} is 1.
round(value, n=0) Rounds a number to the nearest integer.

You can use the n parameter to specify the number of decimal places that you want to retain.

Supported
  • 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, n=1) }} is 1.6.
sum(value) Obtains the sum of the values that you specify. Supported The result returned by {{ sum([1, 2, 3]) }} is 6.

String functions

Function Description Filter Example
string(value) Converts an object to a string. Supported The result returned by {{ string(1.23) }} is 1.23.

The value 1.23 is a string.

capitalize(value) Converts the first letter of a string to an uppercase letter and converts the other letters of the string to lowercase letters. Supported The result returned by {{ capitalize("heLLO World") }} is Hello world.
lower(value) Converts the uppercase letters in a string to lowercase letters. Supported The result returned by {{ lower("FOO") }}is foo.
upper(value) Converts the lowercase letters in a string to uppercase letters. Supported The result returned by {{ upper("foo") }} is FOO.
title(value) Converts a string to title case. In title case, the first letter of each word in a string is in uppercase, whereas the other letters of each word are in lowercase. Supported The result returned by {{ title("hello world") }} is Hello World.
trim(value) Deletes the empty characters at the beginning and end of a string. Supported The result returned by {{ trim(" foo\n") }} is foo.
replace(value, old, new) Replaces the specified characters of a string with new characters. Not supported The result returned by {{ replace("foo", "oo", "ly") }} is fly.
wordcount(value) Counts the number of words in a string. Supported The result returned by {{ wordcount("hello world") }} is 2.
truncate(value, n, end='') Truncates 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.
Not supported
  • The result returned by {{ truncate("foo bar", 5) }} is foo b.
  • The result returned by {{ truncate("foo bar", 5, end="...") }} is foo b...
quote(value) Encloses a string in a pair of double quotation marks (""). Supported
  • The result returned by {{ quote(123) }} is "123".
  • The result returned by {{ quote("foo") }} is "foo".
indent(value, n=4) Indents each line of strings with a specified number of spaces. By default, each line of strings is indented with four spaces.

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

Supported
  • 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
startswith(value, prefix) Checks whether a string starts with a specified substring. Supported The result returned by {{ startswith("football", "foo") }} is true.
endswith(value, suffix) Checks whether a string ends with a specified substring. Supported The result returned by {{ endswith("football", "all") }} is true.
removeprefix(value, prefix) Removes a specified substring from the start of a string. Supported The result returned by {{ removeprefix("football", "foot") }} is ball.
removesuffix(value, suffix) Removes a specified substring from the end of a string. Supported The result returned by {{ removesuffix("football", "ball") }} is foot.

List functions and object functions

Function Description Filter Example
enumerate(value) Converts an iterable object to an indexed sequence and lists the original elements and the subscripts of the original elements. Not supported The result returned by {{ enumerate(["foo", "bar"]) }} is [(0, 'foo'), (1, 'bar')].
list(value) Converts an iterable object to a list. Supported
  • The result returned by {{ list(("foo", "bar")) }} is ['foo', 'bar'].
  • The result returned by {{ list("foo") }} is ['f', 'o', 'o'].
dict(value) Creates a dictionary. The function works in a way similar to the method in which {} is used to create a dictionary. Not supported The result returned by {{ dict(foo=1, bar="hello") }} is {'foo': 1, 'bar': 'hello'}}.
first(value) Returns the first item of a list. Supported The result returned by {{ first([1, 2, 3]) }} is 1.
last(value) Returns the last item of a list. Supported The result returned by {{ last([1, 2, 3]) }} is 3.
sort(value, reverse=true) Sorts the elements of a list.

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

Supported
  • 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].
dictsort(value) Sorts the key-value pairs in an object based on keys and returns an array that consists of the sorted key-value pairs. Supported
  • 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
join(value, d='') Joins the elements of a list by using a specified character.

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

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

Format functions

Function Description Filter Example
escape_markdown(value) Escapes special characters in Markdown. Supported The result returned by {{ escape_markdown("__a__ **b** #c") }} is __a__ **b** #c.
escape_html(value) Escapes special characters in HTML. Supported The result returned by {{ escape_html("<div>") }} is &lt;div&gt;.
to_json(value) Converts an object to the JSON format. Supported
  • 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"}.

Encoding functions and decoding functions

Function Description Filter Example
base64_encoding(value) Encodes the input value by using Base64. Supported The result returned by {{ base64_encoding("foo") }} is Zm9v.
base64_decoding(value) Decodes the input value by using Base64. Supported The result returned by {{ base64_decoding("Zm9v") }} is foo.
md5_encoding(value) Encodes the input value by using MD5. Supported The result returned by {{ md5_encoding("foo") }} is acbd18db4cc2f85cedef654fccc4a4d8.
url_encoding(value) Encodes the input value by using URL encoding. Supported The result returned by {{ url_encoding("https://example.com?a=b&c=d") }} is https%3A%2F%2Fexample.com%3Fa%3Db%26c%3Dd.
url_decoding(value) Decodes the input value by using URL decoding. Supported The result returned by {{ url_decoding("https%3A%2F%2Fexample.com%3Fa%3Db%26c%3Dd") }} is https://example.com?a=b&c=d.

Date functions

Function Description Filter Example
parse_date(value, fmt="%Y-%m-%d %H:%M:%S") Converts the input value to a datetime expression that can return a timestamp value.

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

Supported
  • 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.
format_date(value, tz=None, fmt="%Y-%m-%d %H:%M:%S") Formats the input value.

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 zone list.

Not supported
  • 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.
timestamp(value) Converts a date and time string to a UNIX timestamp.

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.

Supported
  • 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.

Alert functions

Alert functions vary based on the alert context and alert template that you configure. These functions can automatically perceive the following information:
Note An alert function may return different results in different alert contexts.
  • The alert attributes, such as the severity level and status of the triggered alert.
  • The language of the alert template. For example, the language can be Chinese or English.
  • The notification method, such as DingTalk and email.
Function Description Filter Example
format_type(alert.type, locale=None) Converts the type of an alert to a text description.

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.

Supported
  • 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.
format_region(alert.region, locale=None) Converts the region where an alert is triggered to a text description.

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.

Supported
  • 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).
format_severity(alert.severity, locale=None) Converts the severity level of an alert to a text description. The function supports colored fonts.
Note Only DingTalk, Enterprise WeChat, Email, and Message Center support colored fonts.

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.

Supported
  • 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.
format_status(alert.status, locale=None) Converts the status of an alert to a text description. The function supports colored fonts.
Note Only DingTalk, Enterprise WeChat, Email, and Message Center support colored fonts. If you use a notification method that does not support colored fonts, the alert notification remains unchanged after the function is invoked.

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.

Supported
  • 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.
to_list(value) Converts an array or object to a list. Supported
  • 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&#45;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]
annotations_to_list(alert.annotations, locale=None) Converts the annotations of an alert to a list. The function is similar to the to_list(alert.annotations) function. The difference between these two functions lies in that the annotations_to_list function can automatically convert a standard name to a text description. For example, the annotations_to_list function can convert the title field to Title. For more information about standard names, see the "Annotations in alert functions" section of this topic.

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.

Supported
  • 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
blockquote(value) Adds a reference style to an alert notification.
  • 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.
Supported
  • 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>

References

  • Valid values of the locale parameter in alert functions
    Valid value Description
    None or an empty string Specifies to use the language that you select when you configure the alert template.
    en-US Specifies to use English.
    zh-CN Specifies to use Chinese.
  • Annotations in alert functions
    Annotation Mapping value (English)
    title Title
    desc Description
    anomaly_score Anomaly Score
    job_id Task ID
    model_id Model ID
    severity Anomaly Severity
    __pub_alert_app__ Application
    __pub_alert_protocol__ Protocol
    __pub_alert_region__ Region
    __pub_alert_service__ Service
    __ensure_url__ Anomaly Confirmation
    __mismatch_url__ False Positive Confirmation
    __plot_image__ Time Series Chart
    __host_ip__ Machine Address
    __host_group_name__ Machine Group Name
    __cloud_monitor_type__ CloudMonitor