Can you guys show any good way to work with mongodb for database, redis for cache, solr for search engine and hapi for backend

I am doing project for my company. In that we including hapi as backend, mongodb as primary database for caching purpose redis and solr for search engine.

First question, is that specification on my application is right?. My project was like a food app.

Second is, myself actaully connected both redis and mongodb. And its working fine on the system. But when i start with solr, i am deeply blank. To connect solr with mongodb we use mongodb-connector, but i don't how we can connect mongodb-connector with redis.

I understand this is the follow. When we search, it go solr once data was there, then it will check on the redis for the data, if the data not available, then it will go the mongodb. Is my understanding was correct?

I don't know how to connect these three solr, redis and mongodb.

Guys kindly give some explanations or links on these