Spring boot based image catalogue micro service
Every service registers itself with Eureka, and pings Eureka server to notify that it’s alive.
The image service acts as a data source for images, each image has an id, title, and url. Image service has exposed some data through endpoints
The gallery service calls image service to get a list of all images, or maybe only images created during a specific year. The calls from this REST client to the other services can be done using:
1> RestTemplate. An object that’s capable of sending requests to REST API services.
2> FeignClient (acts like a proxy), and provides another approach to RestTemplate.
Both, load balance requests across the services.
It’s a proxy, gateway, an intermediate layer between the users and your services.
Eureka server solved the problem of giving names to services instead of hardcoding their IP addresses.
So, Zuul …
1> Maps between a prefix path, say/gallery/** and a service gallery-service. It uses Eureka server to route the requested service.
2> It load balances (using Ribbon) between instances of a service running on different ports
In the auth service, we:
1> validate the user credentials, and if valid,
2> generate a token, otherwise, throw an exception.
We have common configuration variables, enum classes, or logic, used by multiple services, like the one we had JwtConfig. Instead of duplicating the code, we put it in a separate service that can be included and used as a dependency in other services.