g-leon / Socialpoll

Scalable service that collects, counts and stores votes from Twitter

System Design

• twittervotes pulls the relevant tweet data via the Twitter API , decides what is being voted for (rather, which options are mentioned in the body), and then pushes the vote into NSQ
• counter listens out for votes on the messaging queue and periodically saves results in the MongoDB database. It receives the vote messages from NSQ and keeps an in-memory counter of the results, periodically pushing it to persist the data.
• web is a web server program that will expose the live results.

Quick setup

1. In the top-level folder, start the nsqlookup daemon:

    nsqlookup
   

2. In the same directory, start the nsqd daemon:

    nsqd --lookup-tcp-address=localhost:4160
   

3. Start the MongoDB daemon:

    mongod
   

4. Navigate to the counter folder and build and run it:

    cd counter
    go build -o counter
    ./counter
   

5. Navigate to the twittervotes folder and build and runt it. Ensure that you have the appropriate environment variables set; otherwise, you will see errors when you run the program:

    cd ../twittervotes
    go build -o twittervotes
    ./twittervotes
   

6. Navigate to the api folder and build and run it:

    cd ../api
    go build -o api
    ./api
   

7. Navigate to the web folder and build and run it:

    cd ../web
    go build -o web
    ./web
   

8. Open a browser and head to http://localhost:8081/. Using the user interface, create a poll called "Moods" and input some common enough words as options, such as "happy", "sad", "fail", "success". Once you have created the poll, you will be taken to the view page where you will start to see the results coming in. Wait for a few seconds and see UI updates in real time, showing live, real-time results.