Calculated Fields Expression Language

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Basic syntax and language constructs

Construct	Syntax and Notation
Reserved attribute or tag named `tag`	`tag` (no prefix required)
Attribute named `attr`	`@attr` (use an `@` prefix)
Calculated field named `field`	`#field` (use a `#` prefix)
String literal (quote) For example, `text` or `Quoted "text"`.	`"text"` `"Quoted \"text\""` (Log Search Syntax applies)
Numeric literal (number) For example, `ten`.	`10`
Function named `func` with parameters `x` and `y`	`func(x, y)`
Operator For example, a binary operator `*` with operands `x` and `y`.	`x*y`

Operators

The available operators in order of precedence:

Operator	Description
`()`	A grouping or function call
`!`, `NOT`, `-`	A logical or arithmetic negation
`*`, `/`	Multiplication, division
`+`, `-`	Addition, subtraction
`<`, `<=`, `>`, `>=`	Less than, less than or equal to, greater than, greater than or equal to
`==`, `!=`	Match, does not match
`&&`, `AND`	Logical AND
`\|\|`, `OR`	Logical OR

Functions

The available functions are categorized as follows:

Arithmetic

String

Logical

Arithmetic

abs(num value)

Returns the absolute value of a number.

Example

     A log event has the following attributes:
    - @client_latency = 2
    - @server_latency = 3

     Formula: abs(@client_latency-@server_latency)
     Result: 1

ceil(num value)

Rounds number up to the nearest integer.

Example

     A log event has the following attribute: @value=2.2

     Formula: ceil(@value)
     Result: 3

floor(num value)

Rounds number down to the nearest integer.

Example

     A log event has the following attribute: @value=9.99

     Formula: floor(@value)
     Result: 9

max(num value [, num value, …])

Finds maximum value amongst a set of numbers.

Example

     A log event has the following attribute: @list_of_values=[-1, 1, 5, 5]

     Formula: max(@list_of_values)
     Result: 5

min(num value [, num value, …])

Finds the minimum value amongst a set of numbers.

Example

     A log event has the following attribute: @list_of_values = [-1, 1, 5, 5]

     Formula: min(@list_of_values)
     Result: -1

round(num value, int precision)

Rounds a number. Optionally, define how many decimal places to maintain.

Example

     A log event has the following attribute: @randInt = -1234.01

     Formula: round(@randInt, -1)
     Result: -1230

String

concat(str value [, expr value, …])

Combines multiple values into a single string.

Example

     A log event has the following attributes:
    - @first_name = "Bob"
    - @last_name = "Smith"

     Formula: concat(@first_name, @last_name)
     Result: "Bob Smith"

lower(str string)

Converts string to lowercase.

Example

     A log event has the following attribute: @first_name = "Bob"

     Formula: lower(@first_name)
     Result: "bob"

prefix(str string, int num_chars)

Extracts a portion of text from the beginning of a string.

Example

     A log event has the following attribute: @country="Canada"

     Formula: upper(prefix(@country, 3))
     Result: "CAN"

proper(str string)

Converts string to proper case.

Example

     A log event has the following attribute: @name = "bob SMITH"

     Formula: proper(@name)
     Result: "Bob Smith"

split_before(str string, str separator, int occurrence)

Extracts the portion of text preceding a certain pattern in a string.

Example

     A log event has the following attribute: @row_value = "1,Bob,Smith"

     Formula: split_before(@row_value, ",")
     Result: "1"

split_after(str string, str separator, int occurrence)

Extracts the portion of text following a certain pattern in a string.

Example

     A log event has the following attributes: @row_value = "1,Bob,Smith"

     Formula: split_after(@row_value, ",", 2)
     Result: "Smith"

substring(str string, int start, int end)

Extracts a portion of text from the middle of a string.

Example

     A log event has the following attributes: @row_value = "1,Bob,Smith"

     Formula: substring(@row_value, 3, 3)
     Result: "Bob"

suffix(str string, int num_chars)

Extracts a portion of text from the end of a string.

Example

     A log event has the following attributes: @url = "www.datadoghq.com"

     Formula: suffix(@url, 4)
     Result: ".com"

textjoin(str delimiter, expr value [, expr value, …])

Combines multiple values into a single string with a delimiter in between.

Example

     A log event has the following attributes:
    - @first_name = "Bob"
    - @last_name = "Smith"

     Formula: textjoin(", ", @last_name, @first_name)
     Result: "Smith, Bob"

upper(str string)

Converts string to uppercase.

Example

     A log event has the following attributes: @first_name = "Bob"

     Formula: upper(@first_name)
     Result: "BOB"

Logical

case(expr condition, expr value_if_true [, expr condition, expr value_if_true …], expr value_else)

Evaluates a series of conditions and returns a value accordingly.

if(expr condition, expr if_true, expr if_false)

Evaluates a condition and returns a value accordingly.

Example

     A log event has the following attributes:
    - @origin_country = "USA"
    - @destination_country = "Canada"
    - @origin_continent = "NA"
    - @destination_continent = "NA"

     Formula: if(@origin_country == @destination_country, "national", if(@origin_continent == @destination_continent, "continental", "intercontinental"))
     Result: "continental"

is_null(expr value)

Checks if an attribute or expression is null.

Example

     A log event has the following attributes:
    - @users_online = 5
    - @max_capacity = 0

     Formula: is_null(@users_online / @max_capacity)
     Result: TRUE