Chapter 4 - node.js app. Problem firing app.js via the playbook

[Intertranslations]

In chapter 4 when deploying the app.js app and following the example as laid out in the book and the current git I couldn't get the app.js to run correctly

Adding a debug module to get the contents of forever_list I got the following error.

(Use 'node --trace-warnings ...' to show where the warning was created)
(node:36605) Warning: Accessing non-existent property 'padLevels' of module exports inside circular dependency"

Running the command forever start /usr/local/opt/node/app/app.js manually in the server, I get the following error

warn:    --minUptime not set. Defaulting to: 1000ms
warn:    --spinSleepTime not set. Your script will exit if it does not stay up for at least 1000ms
info:    Forever processing file: /usr/local/opt/node/app/app.js
(node:19444) Warning: Accessing non-existent property 'padLevels' of module exports inside circular dependency
(Use `node --trace-warnings ...` to show where the warning was created)
(node:19444) Warning: Accessing non-existent property 'padLevels' of module exports inside circular dependency

pretty much the same error as with debugging the forever_list var.

I consulted the web about this error but couldn't find a useful solution so I added a scripts section in the package json, run manually the app.js and managed to get the web page showing in port 80.

However I would like to know the why this error occurred and how to solve it. Can anyone suggest the why or how to fix??

---

The content of the playbook, app and package follows below

app.js: vanilla as per git

// Simple Express web server.
// @see http://howtonode.org/getting-started-with-express

// Load the express module.
var express = require('express');
var app = express();

// Respond to requests for / with 'Hello World'.
app.get('/', function(req, res){
    res.send('Hello World!');
});

// Listen on port 80 (like a true web server).
app.listen(80, () => console.log('Express server started successfully.'));

package.json

{
    "name": "examplenodeapp",
    "description": "Example Express Node.js app.",
    "author": "Jeff Geerling <geerlingguy@mac.com>",
    "dependencies": {
      "express": "4.x"
    },
    "engine": "node >= 0.10.6", 
  }
  

playbook.yml: the part pertaining to installing npm, forever and running the app

  - name: Install node.js and npm
    dnf: name=npm state=present enablerepo=epel

  - name: Install Forever to run the node.js app
    npm: name=forever global=yes state=present

  - name: Ensure node.js app folder exists
    file: "path={{ node_apps_location }} state=directory"

  - name: Copy example node.js app to server
    copy:
      src: app
      dest: "{{ node_apps_location }}"

  - name: Install apps dependancies as defined in package.json
    npm: "path={{ node_apps_location }}/app"

  - name: Check list of running node.js apps
    command: /usr/local/bin/forever list
    register: forever_list
    changed_when: false

#  - name: debug forever_list
#    debug: var=forever_list

  - name: Start example Node.js app.
    command: "/usr/local/bin/forever start {{ node_apps_location }}/app/app.js"
    when: "forever_list.stdout.find(node_apps_location + '/app/app.js') == -1"

[Intertranslations]

For anyone that will come up with this problem since I had no feedback after 3 weeks.

The Accessing non-existent property 'padLevels' seems to be an incompatibility with the versions used but does not affect the run of the playbook. If you add a failed_when when getting the forever_list you may proceed with the playbook as described in the book.