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Core Macros

Common Expression Language (CEL) provides powerful built-in macros that let you simplify handling lists, objects, strings, and logical conditions. With these macros, you can create concise, readable expressions, making it easier to manage complex logic.

Objects​

Applies to both lists and maps.

NameReturn TypeDescription
hasboolChecks whether a field or property exists in a list or map.
obj.allboolChecks if a predicate holds for all elements of a collection (either a list or a map).
obj.existsboolChecks if a predicate holds for at least one element of a collection (either a list or a map).
obj.exists_oneboolChecks if a predicate holds for exactly one element of a collection (either a list or a map).
obj.maplistTransforms each element in a list or each key in a map by applying the given function.
obj.maplistTransforms each element in a list or each key in a map by applying a given predicate and transformation.
obj.filterlistFilters a list or map to include only elements that satisfy a condition.
obj.sizeintDetermines the number of entries in a map or elements in a list.

has(field) -> bool​

Checks whether a field or property exists in a list or map.

Example​

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Checks if the x-custom-header is present in the request headers.

obj.all(x,p) -> bool​

Checks if a predicate p holds for all elements of a collection obj (either a list or a map).

Where x is a variable name to be used in p as a reference the element or key.

How it works​

If any predicate for an element evaluates to false, the entire expression will return false. If all predicates evaluate to true, the entire expression evaluates to true. If one predicate fails (evaluates to false), the all() macro will stop evaluating the remaining elements and return false immediately.

Errors in predicates are ignored.

Example​

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Checks if all elements in the list [1, 2, 3] are greater than 0.

obj.exists(x,p) -> bool​

Checks if a predicate p holds for at least one element of a collection obj (either a list or a map).

Where x is a variable name to be used in p as a reference the element or key.

How it works​

If any element satisfies the condition (predicate evaluates to true), the entire expression will return true. If none of the elements satisfy the condition, the result will be false. Evaluation will stop as soon as a predicate evaluates to true. If none of the predicates evaluate to true, the result will be false.

Like all(), errors in predicates are ignored.

Example​

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Checks if any element in the list [1, -2, 3] is greater than 0.

obj.exists_one(x,p) -> bool​

Checks if a predicate p holds for exactly one element of a collection obj (either a list or a map).

Where x is a variable name to be used in p as a reference the element or key.

How it works​

The macro evaluates each element against the predicate and returns true only if exactly one element satisfies the condition. If there are multiple elements that satisfy the predicate, or none at all, the result will be false. If there are multiple matches or none, it will return false.

Unlike all() and exists(), errors in predicates are not ignored.

Example​

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Checks if exactly one element is equal to 2.

obj.map(x,t) -> list​

Transforms each element in a list or each key in a map obj by applying the function defined in the expression t.

Where x is a variable name to be used in p as a reference the element or key.

How it works​

Evaluates each element in the list or each key in the map with the expression t. For a list, it applies t to each element and returns a new list with the transformed elements. For a map, it applies t to each key and returns a new list of keys.

Example​

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obj.map(x,p,t) -> list​

Transforms each element in a list or each key in a map or list obj by applying the function defined in the expression t.

Where x is a variable name to be used in p as a reference the element or key.

Example​

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Returns a list of numbers that are divisible by 2 and multiplies them by two.

obj.filter(x,p) -> list​

Filters a list or map obj to include only elements that satisfy a condition p.

Where x is a variable name to be used in p as a reference the element or key.

Example​

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Returns a list containing only the elements that are greater than 1.

obj.size() -> int​

Determines the number of entries in a map or elements in a list.

Signatures​

  • map.size() -> int
  • size(map) -> int
  • list.size() -> int
  • size(list) -> int

Example​

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Bytes​

NameReturn TypeDescription
bytes.sizeintDetermines the number of bytes in a sequence.

bytes.size() -> int​

Determines the number of bytes in a sequence.

Signatures​

  • bytes.size() -> int
  • size(bytes) -> int

Example​

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Strings​

NameReturn TypeDescription
string.matchesboolTests whether a string matches a given RE2 regular expression.
string.startsWithboolTests whether a string starts with the specified prefix.
string.endsWithboolTests whether a string ends with the specified suffix.
string.containsboolTests whether a string contains the specified substring.
string.sizeintDetermines the length of a string in terms of the number of Unicode codepoints.

string.matches() -> bool​

Tests whether a string matches a given RE2 regular expression. This function provides a simple way to validate patterns in strings.

Signatures​

  • matches(string, regex) -> bool
  • string.matches(regex) -> bool

Example​

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string.startsWith() -> bool​

Tests whether a string starts with the specified prefix.

Signatures​

  • string.startsWith(prefix) -> bool

Example​

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string.endsWith() -> bool​

Tests whether a string ends with the specified suffix.

Signatures​

  • string.endsWith(suffix) -> bool

Example​

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string.contains() -> bool​

Tests whether a string contains the specified substring.

Signatures​

  • string.contains(substring) -> bool

Example​

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string.size() -> int​

Determines the length of a string in terms of the number of Unicode codepoints.

Signatures​

  • string.size() -> int
  • size(string) -> int

Example​

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Timestamps​

NameReturn TypeDescription
ts.getDateintExtracts the day of the month (1-based indexing) from a timestamp.
ts.getDayOfMonthintReturns the day of the month from a timestamp, using zero-based indexing.
ts.getDayOfWeekintReturns the day of the week from a timestamp, using zero-based indexing (0 for Sunday).
ts.getDayOfYearintReturns the day of the year from a timestamp, using zero-based indexing.
ts.getFullYearintReturns the year from a timestamp.
ts.getHoursintReturns the hour from a timestamp or converts a duration to hours.
ts.getMillisecondsintReturns the milliseconds from a timestamp or the milliseconds portion of a duration.
ts.getMinutesintReturns the minutes from a timestamp or converts a duration to minutes.
ts.getMonthintReturns the month from a timestamp, using zero-based indexing (0 for January).
ts.getSecondsintReturns the seconds from a timestamp or converts a duration to seconds.

ts.getDate() -> int​

Extracts the day of the month (1-based indexing) from a timestamp.

Signatures​

  • Timestamp.getDate() -> int (in UTC)
  • Timestamp.getDate(string) -> int (with timezone)

Example​

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ts.getDayOfMonth() -> int​

Returns the day of the month from a timestamp, using zero-based indexing.

Signatures​

  • Timestamp.getDayOfMonth() -> int (in UTC)
  • Timestamp.getDayOfMonth(string) -> int (with timezone)

Example​

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ts.getDayOfWeek() -> int​

Returns the day of the week from a timestamp, using zero-based indexing (0 for Sunday).

Signatures​

  • Timestamp.getDayOfWeek() -> int (in UTC)
  • Timestamp.getDayOfWeek(string) -> int (with timezone)

Example​

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ts.getDayOfYear() -> int​

Returns the day of the year from a timestamp, using zero-based indexing.

Signatures​

  • Timestamp.getDayOfYear() -> int (in UTC)
  • Timestamp.getDayOfYear(string) -> int (with timezone)

Example​

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ts.getFullYear() -> int​

Returns the year from a timestamp.

Signatures​

  • Timestamp.getFullYear() -> int (in UTC)
  • Timestamp.getFullYear(string) -> int (with timezone)

Example​

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ts.getHours() -> int​

Returns the hour from a timestamp or converts a duration to hours.

Signatures​

  • Timestamp.getHours() -> int (in UTC)
  • Timestamp.getHours(string) -> int (with timezone)
  • Duration.getHours() -> int (convert the duration to hours)

Example​

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ts.getMilliseconds() -> int​

Returns the milliseconds from a timestamp or the milliseconds portion of a duration.

Signatures​

  • Timestamp.getMilliseconds() -> int (in UTC)
  • Timestamp.getMilliseconds(string) -> int (with timezone)
  • Duration.getMilliseconds() -> int (extracts the milliseconds portion)

Example​

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ts.getMinutes() -> int​

Returns the minutes from a timestamp or converts a duration to minutes.

Signatures​

  • Timestamp.getMinutes() -> int (in UTC)
  • Timestamp.getMinutes(string) -> int (with timezone)
  • Duration.getMinutes() -> int (convert the duration to minutes)

Example​

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ts.getMonth() -> int​

Returns the month from a timestamp, using zero-based indexing (0 for January).

Signatures​

  • Timestamp.getMonth() -> int (in UTC)
  • Timestamp.getMonth(string) -> int (with timezone)

Example​

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ts.getSeconds() -> int​

Returns the seconds from a timestamp or converts a duration to seconds.

Signatures​

  • Timestamp.getSeconds() -> int (in UTC)
  • Timestamp.getSeconds(string) -> int (with timezone)
  • Duration.getSeconds() -> int (convert the duration to seconds)

Example​

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