design a search engine

Search engine are an essential part of any web apps component that drives traffic and serve analytics.

elasticsearch

Elasticsearch is an open source search engine.

architecture and patterns

A simple use-case for instance would be a typical search engine would consist of a query engine as frontend. A web crawler that crawls some metadata from user input that fetches web searches. Then most importantly, you'll need an index engine that needs to index those metadata into some internal ids with strings of metadata that needs some relationship to data ingested in the index engine server.