77a0262afc1

This is a simple web-api to calculate shortest route.

To calculate the shortest route I am using the following : - Google distance matrix API to fetch distances between each location. - Google node_or_tools lib, to calculate shortest route based on destination.

Originally I wanted to use Google directions API, however, since it consider time as the main cost, I had to revert to node_or_tools.

The steps to find the shortest route is as follows:

User google distance matrix api to fetch distances between each node.
Generate cost matrix based on the distance.
Use node_or_tools to calculate shortest path, as far as I understand main method used to solve the problem is via constraint programming.

Once shortest path is found, we use the original cost matrix to calculate total distance, traveling time.

Architecture

                       __________________________________
                      |___________LOAD BALANCER__________|

                         |             |              |
                      |APP_1|       |APP_2|        |APP_3|
                           |           |             |
                          __________________________
                         |___________Redis__________|

Docker & scaling

As one of the requirements is to Dockerize the app, and make it so to be horizontally scalable. Considering these requirements, I decided to use nginx-proxy as a dynamic load-balancer.

In a ideal scenario we can do the following:

   docker-compose up

   docker-compose scale app=4

nginx-proxy will take care of the load-balancing for us without much configurations.

Note: since we are using nginx-proxy, all request going to the api need to have customized header with {Host:app.local}

Start

To start the - docker-compose up - docker-compose scale app=n

To request shortest route

[Post http://localhost/]

body{
  destinations:[[22.275820,114.155968],[22.271829,114.163070],[22.267377,114.151866],[22.265556,114.163442]]
}

To check token status