Example 9-6 Obtain Textual Representation of Debug Output

The debugging shown later in this example is performed on the JavaScript function fib defined in the module fibunacci_module:

CREATE OR REPLACE MLE MODULE fibunacci_module 
LANGUAGE JAVASCRIPT AS
export function fib( n ) {

    if (n < 0) {
        throw Error("must provide a positive number to fib()");
    }
    if (n < 2) {
        return n;
    } else {
        return fib(n-1) + fib(n-2);
    }
}
/

CREATE OR REPLACE FUNCTION fib( p_value number)
RETURN NUMBER
AS MLE MODULE fibunacci_module
SIGNATURE 'fib(number)';
/

A debugpoint is placed at line 9 and then the DBMS_MLE.PARSE_DEBUG_OUTPUT function is used to view the debug information:

SET SERVEROUTPUT ON;
DECLARE
    l_debugspec JSON;
    l_debugsink BLOB;
    l_debuginfo JSON;
    l_value     NUMBER;
BEGIN
    l_debugspec := JSON ('
    {
        version : "1.0",
        debugpoints : [
            {
                "at" : {
                    "name" : "FIBUNACCI_MODULE",
                    "line" : 9
                },
                "actions" : [
                    { "type" : "watch", "id" : "n" }
                ],
            },
        ]
    }
    ');
    -- create a temporary lob to store the raw 
    -- debug output
    DBMS_LOB.CREATETEMPORARY( l_debugsink, false );

    DBMS_MLE.ENABLE_DEBUGGING( l_debugspec, l_debugsink );

    -- run the application code    
    l_value := fib(4);

    DBMS_MLE.DISABLE_DEBUGGING;

    -- retrieve a textual representation of the debug
    -- output
    l_debuginfo := DBMS_MLE.PARSE_DEBUG_OUTPUT( l_debugsink );
    DBMS_OUTPUT.PUT_LINE(
        json_serialize(l_debuginfo pretty)
    );
END;
/

Result:

[
  [
    {
      "at": {
        "name": "USER1.FIBUNACCI_MODULE",
        "line": 9
      },
      "values": {
        "n": 4
      }
    }
  ],
  [
    {
      "at": {
        "name": "USER1.FIBUNACCI_MODULE",
        "line": 9
      },
      "values": {
        "n": 3
      }
    }
  ],
  [
    {
      "at": {
        "name": "USER1.FIBUNACCI_MODULE",
        "line": 9
      },
      "values": {
        "n": 2
      }
    }
  ],
  [
    {
      "at": {
        "name": "USER1.FIBUNACCI_MODULE",
        "line": 9
      },
      "values": {
        "n": 2
      }
    }
  ]
]