Redis example, but no Mongoose

[amboy00]

In the examples folder, it's showing how to do all of this in Redis. Is there a good example how to pull this off in Mongoose?

[brianviveiros]

+1

I'm assuming that within the individual migrations we should already have access to an open mongoose connection, is that correct?

[thaerlabs]

We have an app that makes use of both mongoose and mongodb driver for some migrations, and schema updates, so I got this working easily this way.

I created a dbConnect.js interface to be required in the migrations.

├── migrations
│   ├── 001-update-user-name-first-last-mongodb.js
│   └── dbConnect.js

in config/migrations.js

var path = require('path');

require('dotenv').load({
  path: path.resolve(__dirname,'../.env')
});

module.exports = {
  local: {
    schema: { 'migration': {} },
    modelName: 'Migration',
    db: process.env.MONGODB_URL || 'mongodb://localhost/example_com_dev'
  }
};

we use .env to load server specific config

and contents of dbConnect.js

var mongoose = require('mongoose');
var MongoClient = require('mongodb').MongoClient;
var mongodb = null;

mongoose.connect(process.env.MONGODB_URL);

module.exports = {
  mongoose: mongoose,
  mongodb: MongoClient.connect(process.env.MONGODB_URL) // mongo Driver return a Promise
};

and then in the migrations (this example is using mongodb driver, mongoose will be easier)

var dbConnect = require('./dbConnect');

exports.up = function (next) {
  // Wait for mongodb Driver to be connected and get the mongodb object
  dbConnect.mongodb.then(function (mongodb) {

    // get the collection needed
    var users = mongodb.collection('www_user');

    //execute the query and get a cursor
    var userCursor = users.find({});

    // loop through the found docs
    userCursor.each(function (err, doc) {
      if (err) {
        console.log(err);
      } else {

        // if it's the last doc null will be returned
        // close the mongodb connection
        // and finish the task
        if (doc === null) {
          mongodb.close();
          next();
        } else {
          // Do what you need to do
          console.log('Fetched:', doc);
        }
      }
    });
  });
};

exports.down = function (next) {
  dbConnect.mongodb.then(function (mongodb) {
    var users = mongodb.collection('www_user');
    var userCursor = users.find({});

    userCursor.each(function (err, doc) {
      if (err) {
        console.log(err);
      } else {
        if (doc === null) {
          mongodb.close();
          next();
        } else {
          console.log('Fetched:', doc);
        }
      }
    });
  });
};