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

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"

geerlingguy / ansible-for-devops

Chapter 4 - node.js app. Problem firing app.js via the playbook #593