VEHICLE AND POLYGON

APP DETAILS

Spring boot App Uses-

1. MongoDB - Supports GeoJson queries and quite easy to handle with spring data and easily scalable.
2. Redis - Caching mechanism used in the application. Caches Location information and Vehicle information for a predefined time period.

Assumptions/Decisions

1. Polling the Vehicle api every time is not a good Idea and that is the reason I have a Redis cache for a predefined time period. This helps not to load the server with lot of requests. Considering scenarios like no request to our API for period of time due to any reason, we are polling for no reason. Also this architecture can be scaled/changed instantly removing or increasing time period depends on scenarios.

2. Also I would love to have query parameter search in /vehicles API instead of retrieving all the vehicles. Because I believe right now Single responsibility of microservices are not completely followed. Right now in-memory searches are happening withing vehicles retrieved in my microservice.

3. Location Cache also present incase we plan to remove a location or change the information.

4. We do not allow to search for all polygons without a polygon json provided, since this result does not makes any sense. Because we return all Vehicles data if no search value provided. And each of then contains which polygon it belongs to.

5. Search supports both ways. a. Search happens on Vehicles first (in-memory) based on vehicle attributes. Then finds matching GeoLocations based on the vehicle coordinates to fill up Polygon Ids.

   b. Stores already found vehicle and polygon ids in cache for later search.

   c. Later Search happens on GeoLocation database for requested polygons based on polygon values specified by user. The above cache will help to fill up vehicle information present inside each polygon. But the polygons with no vehicle info in cache needs to be fetched from database. Hence database $geoNear query is fired for each vehicle not present in cache to find matching polygons. (This is made efficient by specifying db to search in only some polygon ids matched in the above query)

6. Search is built in a way assuming the vehicle data doesnot change a lot. But the vehicle api was giving random data most of the time. For me this is a bit weird, because VEHICLES in an area must be consistent. Only position needs to be changed.

7. Latitude and longitude search is done by considering the first decimal place only to help reviewers data easily than struggling a lot.

URL -> http://localhost:8080/swagger-ui.html#/search-controller/searchUsingGET