Re: Determine the name of the calling function - Mailing list pgsql-novice

Tom, thank you again for your help in solving the "calling function" problem that I posted last week.  I now have a solution I think our shop can live with, that is, if a better one is not found.  The simplest way to explain the actual solution is to just post the code, which I have done below.  Thank you, again.  Jack
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--drop function test_get_function_name_top ();
create or replace function test_get_function_name_top () returns text AS $$
begin
  return test_get_function_name ();
end;
$$ language plpgsql;


--drop function test_get_function_name ();
create or replace function test_get_function_name ()
  returns text as $$
declare
  function_name text;
begin
  -- do some stuff
  -- now need name of calling function (

  /* begin - call function name function */
  declare
    temp_var integer;
    exception_context text;
  begin
    temp_var := 1/0;
  exception
    when division_by_zero then
      get stacked diagnostics exception_context = PG_EXCEPTION_CONTEXT;
      function_name := get_function_name (exception_context);
  end;
  /* end - call function name function */

  -- use function name
  -- do more stuff

  return function_name;

end;
$$ language plpgsql;


--drop function get_function_name (exception_context text);
create or replace function get_function_name (exception_context text)
  returns text as $$
declare
    function_name_loc integer;
begin
  function_name_loc = strpos(exception_context, 'PL/pgSQL function') + 18;
  exception_context = substr(exception_context, function_name_loc);
  function_name_loc = strpos(exception_context, 'PL/pgSQL function') + 18;

  if function_name_loc = 18 then
    return 'unknown';
  end if;
     
  exception_context = substr(exception_context, function_name_loc);
  return substr(exception_context, 1, strpos(exception_context, '(') - 1);

  /* Use the "get_function_name" function to determine the name of the calling function.

  To return the name of the calling function, place the following block of code in the main
  function, such that it will be executed before the name of calling function is required:

  declare
    temp_var integer;
    exception_context text;
  begin
    temp_var := 1/0;
  exception
    when division_by_zero then
      get stacked diagnostics exception_context = PG_EXCEPTION_CONTEXT;
      function_name := get_function_name (function_level, exception_context);
  end;

  Also, define the variable "function_name" as "text" in the main function's "declare" section.
  Note that the function "get_function_name" must be executed within the exception block.

  Following the execution of the exception block, the variable "function_name" will contain
  the name of the calling function.  If the main function was not called by another function,
  then the variable "function_name" will contain the value "unknown".
*/

end;
$$ language plpgsql;

select * from test_get_function_name_top ();

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