Median Microservice

A simple Flask-powered microservice that calculates the median of integers.

Endpoints

• /put (POST/PUT): Store an integer for one minute. Expects a JSON object in the following structure:

  {
      "int": <integer>
  }

• /median (GET): Initiate a median calculation request for all stored integers received over the last minute. Returns a JSON object in the following format:

  {
      "job_id": <job_id>,
      "url": <url_for_result>
  }

• /median-results/<job_id> (GET): See results of a median calculation request.

  • HTTP 200: Calculation complete. Returns a JSON object in the following format:

    {
        "message": "Calculation complete!",
        "median": <median>
    }

  • HTTP 202: Calculation not-yet complete. Returns a JSON object in the following format:

    {
        "message": "Still processing..."
    }

Local Development Setup

Dependencies:

• Redis 3.0.x
• Python 2.7.x
  • Flask==0.10.1
  • numpy==1.11.0
  • redis==2.10.5
  • rq==0.5.6

Installation Instructions

1. Clone this repo to your local machine:

   $ git clone git@github.com:respondcreate/median-microservice.git

2. Create a new virtual environment and install dependencies:

   $ cd median-microservice
   $ virtualenv ENV
   $ source ENV/bin/activate
   $ cd web/
   $ pip install -r requirements.txt

3. Start-up the microservice:

   $ python app.py

4. Open a new shell, activate the virtualenv and start the redis queue consumer (worker.py):

   $ cd median-microservice
   $ source ENV/bin/activate
   $ cd web/
   $ python worker.py

Now visit http://127.0.0.1:5000/put/50 to put your first integer (50) into the microservice!

Running Tests

Run tests with this command (be sure your virtualenv is activated before running):

$ python web/app_tests.py

Docker Commands

The following commands assume you have both docker-machine and docker-compose installed.

Building a docker-machine

1. Create a machine with docker-machine:

   Locally, with virtualbox:

   $ docker-machine create -d virtualbox median-microservice

   On DigitalOcean (assumes you have a valid DigitalOcean token set to the DO_TOKEN environment variable):

   $ docker-machine create -d digitalocean --digitalocean-access-token=$DO_TOKEN median-microservice

   On Amazon AWS (assumes you have ~/.aws/credentials set appropriately):

   $ docker-machine create --driver amazonec2 --amazonec2-zone=b docker-demo

2. Make the median-microservice docker machine your 'current' one:

   $ eval "$(docker-machine env median-microservice)"

Spinning up with docker-compose

1. First, build:

   $ docker-compose build

2. Spin up the server:

   With development settings:

   $ docker-compose up -d

   With production settings:

   $ docker-compose -f docker-compose.yml -f docker-compose.prod.yml up -d