OTTL Functions
The following functions are intended to be used in implementations of the OpenTelemetry Transformation Language that interact with otel data via the collector's internal data model, pdata. These functions may make assumptions about the types of the data returned by Paths.
Factory Functions
Functions
Concat
Concat(delimiter, ...values)
The Concat
factory function takes a delimiter and a sequence of values and concatenates their string representation. Unsupported values, such as lists or maps that may substantially increase payload size, are not added to the resulting string.
delimiter
is a string value that is placed between strings during concatenation. If no delimiter is desired, then simply pass an empty string.
values
is a series of values passed as arguments. It supports paths, primitive values, and byte slices (such as trace IDs or span IDs).
Examples:
-
Concat(": ", attributes["http.method"], attributes["http.path"])
-
Concat(" ", name, 1)
-
Concat("", "HTTP method is: ", attributes["http.method"])
Int
Int(value)
The Int
factory function converts the value
to int type.
The returned type is int64.
The input value
types:
- float64. Fraction is discharged (truncation towards zero).
- string. Trying to parse an integer from string if it fails then nil will be returned.
- bool. If
value
is true, then the function will return 1 otherwise 0.
- int64. The function returns the
value
without changes.
If value
is another type or parsing failed nil is always returned.
The value
is either a path expression to a telemetry field to retrieve or a literal.
Examples:
IsMatch
IsMatch(target, pattern)
The IsMatch
factory function returns true if the target
matches the regex pattern
.
target
is either a path expression to a telemetry field to retrieve or a literal string. pattern
is a regexp pattern.
The function matches the target against the pattern, returning true if the match is successful and false otherwise. If target is nil or not a string false is always returned.
Examples:
-
IsMatch(attributes["http.path"], "foo")
-
IsMatch("string", ".*ring")
SpanID
SpanID(bytes)
The SpanID
factory function returns a pdata.SpanID
struct from the given byte slice.
bytes
is a byte slice of exactly 8 bytes.
Examples:
SpanID(0x0000000000000000)
Split
Split(target, delimiter)
The Split
factory function separates a string by the delimiter, and returns an array of substrings.
target
is a string. delimiter
is a string.
If the target
is not a string or does not exist, the Split
factory function will return nil
.
Examples:
TraceID
TraceID(bytes)
The TraceID
factory function returns a pdata.TraceID
struct from the given byte slice.
bytes
is a byte slice of exactly 16 bytes.
Examples:
TraceID(0x00000000000000000000000000000000)
delete_key
delete_key(target, key)
The delete_key
function removes a key from a pdata.Map
target
is a path expression to a pdata.Map
type field. key
is a string that is a key in the map.
The key will be deleted from the map.
Examples:
-
delete_key(attributes, "http.request.header.authorization")
-
delete_key(resource.attributes, "http.request.header.authorization")
delete_matching_keys
delete_matching_keys(target, pattern)
The delete_matching_keys
function removes all keys from a pdata.Map
that match a regex pattern.
target
is a path expression to a pdata.Map
type field. pattern
is a regex string.
All keys that match the pattern will be deleted from the map.
Examples:
-
delete_key(attributes, "http.request.header.authorization")
-
delete_key(resource.attributes, "http.request.header.authorization")
keep_keys
keep_keys(target, keys...)
The keep_keys
function removes all keys from the pdata.Map
that do not match one of the supplied keys.
target
is a path expression to a pdata.Map
type field. keys
is a slice of one or more strings.
The map will be changed to only contain the keys specified by the list of strings.
Examples:
-
keep_keys(attributes, "http.method")
-
keep_keys(resource.attributes, "http.method", "http.route", "http.url")
limit
limit(target, limit, priority_keys)
The limit
function reduces the number of elements in a pdata.Map
to be no greater than the limit.
target
is a path expression to a pdata.Map
type field. limit
is a non-negative integer.
priority_keys
is a list of strings of attribute keys that won't be dropped during limiting.
The number of priority keys must be less than the supplied limit
.
The map will be mutated such that the number of items does not exceed the limit.
The map is not copied or reallocated.
Which items are dropped is random, provide priority_keys
to preserve required keys.
Examples:
replace_all_matches
replace_all_matches(target, pattern, replacement)
The replace_all_matches
function replaces any matching string value with the replacement string.
target
is a path expression to a pdata.Map
type field. pattern
is a string following filepath.Match syntax. replacement
is a string.
Each string value in target
that matches pattern
will get replaced with replacement
. Non-string values are ignored.
Examples:
replace_all_matches(attributes, "/user/*/list/*", "/user/{userId}/list/{listId}")
replace_all_patterns
replace_all_patterns(target, mode, regex, replacement)
The replace_all_patterns
function replaces any segments in a string value or key that match the regex pattern with the replacement string.
target
is a path expression to a pdata.Map
type field. regex
is a regex string indicating a segment to replace. replacement
is a string.
mode
determines whether the match and replace will occur on the map's value or key. Valid values are key
and value
.
If one or more sections of target
match regex
they will get replaced with replacement
.
Examples:
replace_all_patterns(attributes, "value", "/account/\\d{4}", "/account/{accountId}")
replace_all_patterns(attributes, "key", "/account/\\d{4}", "/account/{accountId}")
replace_pattern
replace_pattern(target, regex, replacement)
The replace_pattern
function allows replacing all string sections that match a regex pattern with a new value.
target
is a path expression to a telemetry field. regex
is a regex string indicating a segment to replace. replacement
is a string.
If one or more sections of target
match regex
they will get replaced with replacement
.
Examples:
replace_pattern(resource.attributes["process.command_line"], "password\\=[^\\s]*(\\s?)", "password=***")
replace_match
replace_match(target, pattern, replacement)
The replace_match
function allows replacing entire strings if they match a glob pattern.
target
is a path expression to a telemetry field. pattern
is a string following filepath.Match syntax. replacement
is a string.
If target
matches pattern
it will get replaced with replacement
.
Examples:
replace_match(attributes["http.target"], "/user/*/list/*", "/user/{userId}/list/{listId}")
set
set(target, value)
The set
function allows users to set a telemetry field using a value.
target
is a path expression to a telemetry field. value
is any value type. If value
resolves to nil
, e.g. it references an unset map value, there will be no action.
How the underlying telemetry field is updated is decided by the path expression implementation provided by the user to the ottl.ParseStatements
.
Examples:
-
set(attributes["http.path"], "/foo")
-
set(name, attributes["http.route"])
-
set(trace_state["svc"], "example")
-
set(attributes["source"], trace_state["source"])
truncate_all
truncate_all(target, limit)
The truncate_all
function truncates all string values in a pdata.Map
so that none are longer than the limit.
target
is a path expression to a pdata.Map
type field. limit
is a non-negative integer.
The map will be mutated such that the number of characters in all string values is less than or equal to the limit. Non-string values are ignored.
Examples:
-
truncate_all(attributes, 100)
-
truncate_all(resource.attributes, 50)