High-Level Design

Describe the overall system architecture. Identify the main components needed to solve the problem end-to-end. Use the diagramming tool to create a block diagram.

I think the basic design in the diagram could suffice. The administrative endpoints should be fairly low volume. I don't foresee users creating a lot of shortlinks all the time. These endpoints should simply take the CRUD operations and utilize the database directly.

For the database I think we could use postgres. It's a great general purpose database an I know it well. The main table will be a shortlink table.

create table shortlink (

id serial primary key;

shortcode text;

redirect_url text not null;

user_id text not null;

created_at timestamptz;

last_updated_at timestamptz;

);

Generally the POST /api/v1/shortlinks endpoint should insert the row. Since we're using serial, the id should auto increment. The shortcode should be a base62 encoding of the id and we can update the row to set shortcode value once we get back the id value from the initial insert. We will also want to index the shortcode column for fast lookups.

The main endpoint will need to scale horizontally and be highly available. There are a few approaches we could take to scale it, but I think to start, we could just use a basic web server and implement an in-memory LRU cache. For big events this could provide a very fast response where many users are requesting the same shortlink because it would be able to skip going to the database and return an in-memory redirect url. For shortlinks not in the LRU cache, we would go to the database and then store in the LRU cache.

To achieve HA, we could use a cloud provider like GCP or AWS. We could use an orchestration layer like k8s or utilize managed services to host our webserver(s). We could also put together a disaster recovery plan that includes automatic failover to other AZ's or regions.

If we're worried about the webservers eventually not being able to hold a large enough LRU cache in memory to be practical, we could start to look at other caching alternatives. Redis or memcached. We could also explore edge servers and more advanced caching options.

Submissions

Displaying Solutions with Scores Ranging from 1 to 10

Submissions

Displaying Solutions with Scores Ranging from 1 to 10