Logs in postgresql

Question

Good morning Everybody, I have a trigger to log in INSERT, UPDATE and DELETE in the postgresql, but the way I’m logging in, it’s as if the bank’s own user had done the operation. I needed to be saved the system user who modified them.

Creating a schema for the table CREATE SCHEMA logging;

Table creation

CREATE TABLE logging.logs (
        id              serial,
        data            timestamp without timezone DEFAULT now(),
        schema          text,
        tabela          text,
        operacao        text,
        usuario         text DEFAULT current_user <--- pegando o usuário do banco,
        valor_novo      json,
        valor_antigo    json
);

Creation of the function

CREATE FUNCTION change_trigger() RETURNS trigger AS $$
       BEGIN
         IF TG_OP = 'INSERT'
         THEN INSERT INTO logging.logs (
                tabela, schema, operacao, valor_novo
              ) VALUES (
                TG_RELNAME, TG_TABLE_SCHEMA, TG_OP, row_to_json(NEW)
              );
           RETURN NEW;
         ELSIF  TG_OP = 'UPDATE'
         THEN INSERT INTO logging.logs (
             tabela, schema, operacao, valor_novo, valor_antigo
           )
           VALUES (TG_RELNAME, TG_TABLE_SCHEMA, TG_OP, row_to_json(NEW), row_to_json(OLD));
           RETURN NEW;
         ELSIF TG_OP = 'DELETE'
         THEN INSERT INTO logging.logs
             (tabela, schema, operacao, valor_antigo)
             VALUES (
               TG_RELNAME, TG_TABLE_SCHEMA, TG_OP, row_to_json(OLD)
             );
             RETURN OLD;
         END IF;
       END;
$$ LANGUAGE 'plpgsql' SECURITY DEFINER;

Creating the Trigger in the desired table

CREATE TRIGGER t BEFORE INSERT OR UPDATE OR DELETE ON tabela_exemplo
        FOR EACH ROW EXECUTE PROCEDURE change_trigger();

The user table is in the app schema, ie I access so -> app.users.

Thank you in advance.