AppServer

About

• Part of the service oriented architecture for Tetraflix, a Netflix clone designed to answer the following business question: Among users who don’t leave ratings, do recommendations based on modeled user genre preferences outperform recommendations based on fixed genre preferences?
• Check out our detailed App Plan of the whole system

AppServer's role

• Generate and manage inventory of 300,000 movies and genre profiles for each movie
• store and update personalized recommendations for millions of users
• calculate most popular movies by genre at regular intervals
• serve requested movies to clients via a RESTful API
• connect with other services via Amazon SQS to process data asynchronously throughout the system

Contributing

Adhere to airbnb style guide. See CONTRIBUTING.md for contribution guidelines.

System Data Flow

Requirements

• Node 6.9.x
• Postgresql 9.6.x
• MongoDB 3.6.x
• Elasticsearch 5.6.3
• Kibana 5.6.3

App Server Architecture

Schema Design

I/O

Inputs:

• Current recommendations for each user,
  • Update user recommendations (fast db for serving client)

{
  userId: 534356757834,
  rec: [23, 105, 765, 32, 479]
} 

• Session data
  • Update view count for each movie when progress = 1 (movie db)
  • Periodically update genre recommendations based on view count (fast db for user recommendations)

{
  userId: 534356757834,
  events: [
    {
      movie: {
        id: 543,
      },
      progress: 1,
      timestamp: 2017-09-08 12:50PM
    }, {
      movie: {
        id: 155,
      },
      progress: 0.7,
      timestamp: 2017-09-08 2:50PM
    }
  ]
}

Outputs:

• Current movie recommendations for a user and Serve up “continue watching” movies to client (change movie default progress from 0 to wherever they left off) (GET ‘/tetraflix/recommendations/:user’)

{
  recommendations: [
    {
      id: 8675309,
      title:'Lord of the Rings',
      profile: {[genre breakdown]},
      progress: 0
    },
    {
      id: 4879823,
      title:'The Talented Mr.Ripley',
      profile: {[genre breakdown]},
      progress: 0
    }
  ],
  currentlyWatching: [
    {
      id: 234523,
      title:'Kahaani',
      profile: {[genre breakdown]},
      progress: 0.3
    },
    {
      id: 857636,
      title:'Memento',
      profile: {[genre breakdown]},
      progress: 0.7
    }
  ]
} 

• Serve up movies by genre, sorted in order of popularity (GET ‘/tetraflix/genre/:genre’)

{
  genre: [
    {
      id: 34532,
      title: 'Amelie',
      profile: {[genre breakdown]},
      progress: 0
    },
    {
      id: 567490,
      title: 'Star Wars',
      profile: {[genre breakdown]},
      progress: 0
    }
  ]
}