Careeroza

Real World Example

Netflix: The Famous Migration

In 2008 a database corruption stopped Netflix DVD shipping for three days. Netflix then moved from one big Java monolith in its own data centre to hundreds of microservices on AWS (the migration took about seven years). Today separate services handle sign-up, the catalogue, recommendations, playback, billing and more. Netflix built and open-sourced many of the tools that later became part of Spring Cloud (Eureka, Hystrix, Zuul, Ribbon).

Amazon, Uber and Swiggy

CompanyStarted asSplit into services such as
AmazonOne big C++/Perl app ("Obidos")catalogue, cart, checkout, recommendations, reviews; every team exposes an API ("two-pizza teams")
UberA Python monolith for one cityrider, driver, trips, pricing (surge), maps/ETA, payments, notifications
SwiggyA monolith for food deliveryrestaurant listing, menu, cart, order, delivery partner assignment, payments, Instamart
FlipkartA monolithcatalogue, search, cart, checkout, payments, logistics (Ekart)

Note: All of them started with a monolith and split it when the team and traffic grew. None started with 500 services on day one.

How a Swiggy Order Crosses Services

App --> API Gateway --> order-service
                          |-- GET  restaurant-service/restaurants/42/open   -> true
                          |-- POST pricing-service/quote                    -> Rs 348 incl. fees
                          |-- POST payment-service/charges                  -> PAID
                          |-- publish event "OrderPlaced"
                                    |--> restaurant-service  (show order to kitchen)
                                    |--> delivery-service    (assign a delivery partner)
                                    |--> notification-service(push "Order confirmed")

ShopEase in Code: One Endpoint, Two Services

The same "place order" feature, seen from the client. The client calls only order-service; order-service calls product-service behind the scenes (we build this in the Building Your First Microservices module):

Example

Request and response:

curl -X POST localhost:8082/api/orders \
  -H "Content-Type: application/json" \
  -d '{"userId": 7, "items": [{"productId": 1, "quantity": 2}]}'

Example output

HTTP/1.1 201 Created
Location: /api/orders/1001
Content-Type: application/json

{"id":1001,"userId":7,"status":"CREATED","total":2998.00,
 "items":[{"productId":1,"productName":"boAt Rockerz 450","unitPrice":1499.00,"quantity":2}]}