Hapijs and iToolkit async issue

The following is a complete debug test of an issue encountered when trying to use Hapijs and iToolkit in async fashion. Using iToolkit in sync fashion works, and async doesn't.

Environment:

IBM i v7.2
Node v6.9.1 with latest SI64400 PTF installed.

Steps to recreate the issue:

$ export PATH=/QOpenSys/QIBM/ProdData/OPS/Node6/bin:$PATH
$ mkdir hapijs_itoolkit_bug && cd hapijs_itoolkit_bug
$ npm init
$ npm install hapi --save

Put the following in hapijs_itoolkit_bug/server.js

'use strict';

const Hapi = require('hapi');
const server = new Hapi.Server();
server.connection({ 
  host: '0.0.0.0', 
  port: process.env.PORT || 8000
});

server.route([
  {
    method: 'GET',
    path:'/itoolkit', 
    handler: function (request, reply) {
      var xt = require("/QOpenSys/QIBM/ProdData/OPS/Node6/os400/xstoolkit/lib/itoolkit");
      var conn = new xt.iConn("*LOCAL");
      var sysVal = "QCCSID";
      var outBuf = [
             [0, "10i0"],
             [0, "10i0"],
             ["", "10A"],
             ["", "1A"],
             ["", "1A"],
             [0, "10i0"],
             [0, "10i0"]
      ];
      var errno = [
             [0, "10i0"],
             [0, "10i0", {"setlen":"rec2"}],
             ["", "7A"],
             ["", "1A"]
      ];
      var pgm = new xt.iPgm("QWCRSVAL", {"lib":"QSYS"});
      pgm.addParam(outBuf, {"io":"out", "len":"rec1"});
      pgm.addParam(0, "10i0", {"setlen":"rec1"});
      pgm.addParam(1, "10i0");
      pgm.addParam(sysVal, "10A");
      pgm.addParam(errno, {"io":"both", "len" : "rec2"});
      conn.add(pgm);
      conn.run(function(str) {
        var results = xt.xmlToJson(str)
        reply({ results: results })
      });      
    }
  },
  {
    method: 'GET',
    path:'/clear', 
    handler: function (request, reply) {
      reply({name:'value'})
    }
  }
])

server.start((err) => {
  if (err) 
    throw err;
  console.log('Server running at:', server.info.uri);
});

Start the web server.

$ npm start                               

> hapijs_itoolkit_bug@1.0.0 start /home/USR707MS/hapijs_itoolkit_bug            
> node server.js                                                                

Server running at: http://0.0.0.0:8000

Watch this video to see how I work to prove that hapijs hangs when iToolkit is involved. It stops hanging if I make an additional call to a different endpoint that doesn't involve the iToolkit.

In the video I show that the async DB2 driver isn't working as expected. I then change it to use the sync approach with the following code change. After making this change it works; it doesn't hang.

      conn.run(function(str) {
        var results = xt.xmlToJson(str)
        reply({ results: results })
      }, true);      // <------ true means set to synchronous

Below is an excerpt from istoredp.js (the part of nodejs-itoolkit that talks to DB2).

      var stmt = new db.dbstmt(conn);
      if(sync == true) {  // Sync Mode
        stmt.prepareSync(sql);
        stmt.bindParamSync([
          [xipc, db.SQL_PARAM_INPUT, 1],
          [xctl, db.SQL_PARAM_INPUT, 1],
          [xml_input_script, db.SQL_PARAM_INPUT, 0],
          [xmlOut, db.SQL_PARAM_OUTPUT, 0],
        ]);
        stmt.executeSync(function(outArray) {  //out is an array of the output parameters.
          if(outArray.length == 1)
            callback(outArray[0]);  // For XML service, there is always only one return XML output. So handle it directly.
          else
            callback(outArray);  // For multiple return result, caller should handle it as an array.
          stmt.close();
          conn.disconn();
          conn.close();
        });
      } else {  // Async Mode
        stmt.prepare(sql, function(){
          stmt.bindParam([
            [xipc, db.SQL_PARAM_INPUT, 1],
            [xctl, db.SQL_PARAM_INPUT, 1],
            [xml_input_script, db.SQL_PARAM_INPUT, 0],
            [xmlOut, db.SQL_PARAM_OUTPUT, 0],
          ], function(){
            stmt.execute(function(outArray) {  //out is an array of the output parameters.
              if(outArray.length == 1)
                callback(outArray[0]);  // For XML service, there is always only one return XML output. So handle it directly.
              else
                callback(outArray);  // For multiple return result, caller should handle it as an array.
              stmt.close();
              conn.disconn();
              conn.close();
            });
          });
        });
      }

After reviewing the code it appears the issue is somewhere within the closed source components of the stmt object, so I can't debug further.

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