MissingSchemaError in NodeJS app on Heroku server

Question

My app is successfully works on my local.

When I push it to a heroku server, sometimes it crashes with this error:

2012-12-28T10:00:53+00:00 heroku[web.1]: Starting process with command `node server.js`
2012-12-28T10:00:54+00:00 app[web.1]: 
2012-12-28T10:00:54+00:00 app[web.1]: /app/node_modules/mongoose/lib/index.js:261
2012-12-28T10:00:54+00:00 app[web.1]:       throw new mongoose.Error.MissingSchemaError(name);
2012-12-28T10:00:54+00:00 app[web.1]:             ^
2012-12-28T10:00:54+00:00 app[web.1]: MissingSchemaError: Schema hasn't been registered for model "Activity".
2012-12-28T10:00:54+00:00 app[web.1]: Use mongoose.model(name, schema)
2012-12-28T10:00:54+00:00 app[web.1]:     at Mongoose.model (/app/node_modules/mongoose/lib/index.js:261:13)
2012-12-28T10:00:54+00:00 app[web.1]:     at Object.<anonymous> (/app/app/models/user.js:8:25)
2012-12-28T10:00:54+00:00 app[web.1]:     at Module._compile (module.js:449:26)
2012-12-28T10:00:54+00:00 app[web.1]:     at Object.Module._extensions..js (module.js:467:10)
2012-12-28T10:00:54+00:00 app[web.1]:     at Module.load (module.js:356:32)
2012-12-28T10:00:54+00:00 app[web.1]:     at Function.Module._load (module.js:312:12)
2012-12-28T10:00:54+00:00 app[web.1]:     at Module.require (module.js:362:17)
2012-12-28T10:00:54+00:00 app[web.1]:     at require (module.js:378:17)
2012-12-28T10:00:54+00:00 app[web.1]:     at /app/server.js:23:3
2012-12-28T10:00:54+00:00 app[web.1]:     at Array.forEach (native)
2012-12-28T10:00:55+00:00 heroku[web.1]: Process exited with status 1
2012-12-28T10:00:55+00:00 heroku[web.1]: State changed from starting to crashed

In my server.js, I am loading models with this code:

var models_path = __dirname + '/app/models'
fs.readdirSync(models_path).forEach(function (file) {
     require(models_path+'/'+file)
})

And my activity.js is:

var mongoose = require('mongoose')
  , Schema = mongoose.Schema
  , moment = require('moment')

var schemaOptions = {
    toJSON: {
      virtuals: true
    }
};
var ActivitySchema = new Schema({
    venue: {type : Schema.ObjectId, ref : 'Venue'}
  , user: {type : Schema.ObjectId, ref : 'User'}
  , createdAt: {type : Date, default : Date.now}
  , rate: Number
  , message : String
  , source : String 
}, schemaOptions)
mongoose.model('Activity', ActivitySchema)

ActivitySchema.index({ "user": 1, "venue"  : 1 }, { unique: true })

var modifiedAt = require('../../config/plugins.js');
ActivitySchema.plugin(modifiedAt, { index: false });

ActivitySchema.virtual('summary').get(function () {
        moment.lang('en');

    return moment(this.createdAt).fromNow()  + ' via ' + this.source;
});

Weird thing is, sometimes the app crashes but sometimes it works. What can I do to solve it?

Answer 1

What I had to do in my code to resolve the 'MissingSchemaError' in mongoose was to export a function that takes mongoose as the parameter.

Something like this.

module.exports = function (mongoose) {

    var GeoSchema = new mongoose.Schema({
        loc:{ type:[Number], index:'2d'}
    });

    return GeoSchema;
};

Answer 2

I ran into the same issue. I had modified my users module so it would create a corresponding profile document that corresponded with the users module. Having that users module load the Profile schema would throw the same error when I loaded it at the top of the file. When I put it within the scope of the code I was using it fixed the problem.

    var Profile = mongoose.model('Profile');

I had to move the above line into the code (I think it's a timing thing, where I was trying to use it before mongo had been made a