Kotlin function error handling
If a handler reports a function runtime or loading error, the runtime environment automatically captures the error and returns a JSON document with the error type in the response. For more information about the JSON document format, see Calling a function. Error info is written to the execution log.
Examples of error handling
Let's assume a handler returns a sum of numbers. An empty request will cause the handler to throw IllegalArgumentException.
Function code:
fun handle(request: IntArray): Int {
if (request.isEmpty()) throw IllegalArgumentException()
return request.sum()
}
Case 1. When invoking a function, the user provides the [1, 22, 333] array:
curl \
--header "Authorization: Bearer <IAM_token>" \
--data "[1, 22, 333]" \
"https://functions.yandexcloud.net/<function_ID>?integration=raw"
The function returns 356, the sum of the numbers.
Case 2. The user provides an empty array:
curl \
--header "Authorization: Bearer <IAM_token>" \
--data "[]" \
"https://functions.yandexcloud.net/<function_ID>?integration=raw"
The runtime environment captures the exception and generates a JSON document that contains an error message (errorMessage field), error type (errorType field), and stack trace (stackTrace field).
JSON document returned:
{
"errorMessage": "An exception has occurred in the user code, details: java.lang.IllegalArgumentException. [ERR_USER_CODE]",
"errorType": "IllegalArgumentException",
"stackTrace": [
{
"function": "handle",
"file": "Handler.kt",
"line": 2
},
...
]
}
Case 3. The user provides a string instead of numbers, which results in a deserialization error:
curl \
--header "Authorization: Bearer <IAM_token>" \
--data "notanarray" \
"https://functions.yandexcloud.net/<function_ID>?integration=raw"
JSON document returned:
{
"errorMessage": "An exception has occurred during request deserialization. Details: com.squareup.moshi.JsonEncodingException: Use JsonReader.setLenient(true) to accept malformed JSON at path $. [ERR_INVALID_REQUEST]",
"errorType": "FunctionException"
}