.NET Core function error handling

If a handler reports a .NET Core function runtime or loading error, the runtime environment automatically intercepts the error and responds by returning a JSON document with the error type info. For more information about the JSON document format, see Calling a function.

The error info is also written to the execution log. You can view the log via the Yandex Cloud CLI or the management console.

Examples of error handlingExamples of error handling

Case 1: User code goes outside the array boundaries, resulting in IndexOutOfRangeException. The runtime environment intercepts the exception and generates a JSON document stating the error message (errorMessage field), error type (errorType field), and stack trace (stackTrace field).

Function code:

public class Handler {
  public int FunctionHandler(byte[] input) {
    readonly var array = new int[]{1, 2, 3, 4, 5};
    // at this point, the function throws an IndexOutOfRangeException
    return array[15];
  }
}

JSON document returned:

{
  "errorMessage": "Index was outside the bounds of the array",
  "errorType": "System.IndexOutOfRangeException",
  "stackTrace": [
    ...
  ]
}

Case 2: User code indicates an error by throwing an exception from the function.

Function code:

public class Handler {
  public int FunctionHandler(byte[] input) {
    throw new SystemException("Some error message");
  }
}

JSON document returned:

{
  "errorMessage": "Some error message",
  "errorType": "System.SystemException",
  "stackTrace": [
    ...
  ]
}