Case Conversion Functions

OTTL provides two approaches for converting string case formats:

Dynamic Case Conversion with ConvertCase

The ConvertCase function accepts a case type parameter, making it useful when the case format needs to be determined dynamically.

Syntax: ConvertCase(value, caseType)

• value: the bracket notation location of the string field
• caseType: the desired case format (“lower”, “upper”, “snake”, “camel”)

Example: Converting to Uppercase

Input

{
	"_type": "log",
	"attributes": {
		"method": "post"
	},
	"body": "172.28.34.214 - - [06/Dec/2024:03:39:40 +0000] \"POST /admin/users HTTP/1.1\" 204 0 \"-\" \"lambda.amazonaws.com\"",
	"resource": {...},
	"timestamp": 1733456539663
}

Statement

set(attributes["method"], ConvertCase(attributes["method"], "upper"))

Output

{
	"_type": "log",
	"attributes": {
		"method": "POST"
	},
	"body": "172.28.34.214 - - [06/Dec/2024:03:39:40 +0000] \"POST /admin/users HTTP/1.1\" 204 0 \"-\" \"lambda.amazonaws.com\"",
	"resource": {...},
	"timestamp": 1733456574823
}

The method attribute was converted to uppercase.

Case-Specific Conversion Functions

For fixed case conversions, OTTL provides dedicated functions for each case format:

• ToLowerCase(value) - converts to lowercase (e.g., “HELLO_WORLD” → “hello_world”)
• ToUpperCase(value) - converts to uppercase (e.g., “hello_world” → “HELLO_WORLD”)
• ToCamelCase(value) - converts to PascalCase with first letter capitalized (e.g., “hello_world” → “HelloWorld”)
• ToSnakeCase(value) - converts to snake_case (e.g., “HelloWorld” → “hello_world”)

These functions are simpler when the case format is known at configuration time.

Example: Multiple Case Conversions

Input

{
	"_type": "log",
	"body": {
		"test_string": "hello_world",
		"run": 23
	},
	"resource": {...},
	"timestamp": 1727750400000
}

Statement

set(body["camel_case"], ToCamelCase(body["test_string"]))
set(body["lower_case"], ToLowerCase(body["test_string"]))
set(body["snake_case"], ToSnakeCase(body["test_string"]))
set(body["upper_case"], ToUpperCase(body["test_string"]))

Output

{
	"_type": "log",
	"body": {
		"test_string": "hello_world",
		"camel_case": "HelloWorld",
		"lower_case": "hello_world",
		"snake_case": "hello_world",
		"upper_case": "HELLO_WORLD",
		"run": 23
	},
	"resource": {...},
	"timestamp": 1727750400000
}

Each function converted the string to its respective case format.