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VOOZH | about |
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VOOZH | about |
In monitor notification messages, you can modify the output of template variables using the eval syntax, which enables several different mathematical operations and functions on template variables with a numerical or string value.
Evaluation operators allow you to perform basic arithmetic operations on a numerical template variable. The syntax uses the following format. Note: The expressions must be wrapped in quotation marks (").
{{eval "TEMPLATE_VARIABLE_NAME+1-2*3/4"}}
The following operators are supported:
| Operator | Description |
|---|---|
| + | Addition |
| - | Subtraction |
| * | Multiplication |
| / | Division |
| ^ | Exponentiation |
| % | Modulo |
The {{last_triggered_at_epoch}} template variable returns the UTC time when a monitor last triggered in milliseconds epoch format.
Evaluation operators can be used to subtract 15 minutes (15 * 60 * 1000 milliseconds) with the following:
{{eval "last_triggered_at_epoch-15*60*1000"}}
This is useful for creating time-scoped links in your monitor notification message to other pages in Datadog or other workflow tools. For instance, use the evaluation operators on {{last_triggered_at_epoch}} to create a time-scoped link to the Datadog Log Explorer:
https://app.datadoghq.com/logs?from_ts={{eval "last_triggered_at_epoch-15*60*1000"}}&to_ts={{last_triggered_at_epoch}}&live=false
You can combine a modulo % evaluation of the last_triggered_at_epoch variable with {{#is_exact_match}}{{/is_exact_match}} to customize the routing of notifications based on time of day (UTC):
{{#is_exact_match (eval "int(last_triggered_at_epoch / 3600000 % 24)") "8" "9" "10" "11" "12" "13"}}
Handle that should receive notification if time is between 8AM and 2PM UTC
{{/is_exact_match}}
Note: If you need to evaluate your monitor on a schedule, see Custom Schedules instead.
The value of a template variable can be used as the input for evaluation functions to change the formatting of the template variable or perform a mathematical operation on the value (if applicable). The syntax uses the following format. Note: The expressions must be wrapped in quotation marks (").
{{eval "function(TEMPLATE_VARIABLE_NAME)"}}
The following functions change how the value of a numerical template variable is formatted:
| Function | Description |
|---|---|
| humanize_bytes(var) | Returns a human readable formatting of var bytes |
| humanize_bits(var) | Returns a human readable formatting of var bits |
| abs(var) | Returns the absolute value of var |
| int(var) | Returns var as a floored integer; that is, the numbers to the left of the decimal point. For example: if var = 12.345, then int(var) returns 12. |
| float(var) | Returns var as a float |
| trunc(var) | Returns var as an integer, an alias of the int function |
| dec(var) | Returns the numbers to the right of the decimal point. For example: if var = 12.345, then dec(var) returns 0.345. |
The following functions use the value of a numerical template variable as the input to a mathematical function:
| Function | Description |
|---|---|
| round(var) | Returns var rounded to the nearest integer |
| round(var, n) | Returns var rounded to a specified number of digits (n). For example: round(12.376, 2) = 12.38 |
| ceil(var) | Returns the ceiling of var (the smallest integer that is greater than or equal to var) |
| floor(var) | Returns the floor of var (the largest integer that is less than or equal to var) |
| sgn(var) | Returns the value of the sign function evaluated at var: sgn(var) = 1 if var > 0 sgn(var) = 0 if var = 0 sgn(var) = -1 if var < 0 |
| to_bool(var) | Returns true if var = 1 Returns false if var = 0 |
| exp(var) | Returns e (the base of the natural logarithm) raised to the power of var |
| log10(var) | Returns the base-10 logarithm of var |
| sin(var) | Returns the sine of var radians |
| sinh(var) | Returns the hyperbolic sine of var |
| asin(var) | Returns the arc sine of var, in radians |
| asinh(var) | Returns the inverse hyperbolic sine of var |
| cos(var) | Returns the cosine of var radians |
| cosh(var) | Returns the hyperbolic cosine of var |
| acos(var) | Returns the arc cosine of var, in radians |
| acosh(var) | Returns the inverse hyperbolic cosine of var |
| tan(var) | Returns the tangent of var radians |
| tanh(var) | Returns the hyperbolic tangent of var |
| atan(var) | Returns the arc tangent of var, in radians |
| atan2(var1, var2) | Returns atan(var1 / var2), in radians |
| atanh(var) | Returns the inverse hyperbolic tangent of var |
If the decimal places of the {{value}} template variable are unnecessary for your particular use case, use the int function to evaluate {{value}} as an integer to improve readability and remove the decimals:
{{eval "int(value)"}}
If {{value}} is evaluating to a large number of bytes or bits, use the humanize_bytes or humanize_bits function to convert the number to a different higher order memory unit like GB or MB to improve readability:
{{eval "humanize_bytes(value)"}}
{{eval "humanize_bits(value)"}}
The following functions can be used to perform certain operations on strings variables:
| Function | Description |
|---|---|
| upper(var) | Returns a string converted to uppercase letters |
| lower(var) | Returns a string converted to lowercase letters |
| substring(var, start, end) | Extracts characters from a string, between two specified indexes (start, end). The third parameter is optional. For example: substring(“host:D”, 5) = “D” |
| strip(var, characters) | Remove the leading and trailing characters. When the second parameter is null, it removes spaces at the beginning and at the end of the string. For example: strip(" host:E “) = “host:E” strip(“abchost:Eabc”, “abc”) = “host:E” |
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