fuzzy-fortnight

This project a starting point for understanding common Microservice architecture patterns by example of a proof-of-concept application built with Spring Boot, Spring Cloud, and Docker.

Tech Stack

The Technical Stack used for this service is,

• Language - JAVA
• Spring Boot Web Application
• Spring Cloud
• Netflix OSS
• Docker

Code Structure

This project is structured like below directory tree.

|-microservices
   |---composite
   |-----word-query-service
   |---core
   |-----antonyms-query-service
   |-----sounds-like-query-service
   |-----synonyms-query-service
   |---support
   |-----auth-service
   |-----eureka-discovery-service
   |-----hystrix-dashboard-service
   |-----turbine-aggregator-service
   |-----zuul-edge-service

Each component inside the composite, core and support folders are maven modules and git sub modules.

Requirement 1

As an end user, I want to know the synonyms of a given word. It requires authentication and user role is normal.

Example -

Input - happy

Output - content

Requirement 2

As an end user, I want to know the antonyms of a given word. It requires authentication and user role is admin.

Example -

Input - late

Output - early

Requirement 3

As an end user, I want to know the sounds like of a given word. It requires authentication and user role is normal.

Example -

Input - elefint

Output - elephant

Requirement 4

Apply API rate limit on above API's per user.

System Diagram

Infrastructure Services

eureka-discovery-service - It discovers the rest of the services in this system. All the other systems register them into this service. This is basically server side discovery pattern. We are using the Netflix Eureka server for that. This is developed using Spring Boot, Cloud with Eureka server.

zuul-edge-service - It is an edge service which is exposed to the public internet. It acts as a gateway to all other micro services. We are using the Netflix Zuul for that. It has routes for functional services. It also makes authorisation based on the bearer token in request. It is developed using Spring Boot, Cloud, Security with Zuul. Based on the authorized user name applies API rate limit and it is configurable at application.yml file.

ribbon - It is part of zuul edge service where zuul uses for routing the request to more than one instance.

circuit-breaker - It is enabled in composite service and other functional services for fallback mechanism incase of exception.

turbine-aggregator-service - It is an aggregator service which will collect the hystrix details from all the composite and functional services and maintain that is stream of events for 2 mins(by default).

hystrix-dashboard-service - It is an user interface service and provide nice representation on turbine stream of events.

Functional Services

We are going to decompose our business requirement into services. There are a number of strategies that can help:

- Decompose by business capability and define services corresponding to business capabilities.
- Decompose by domain-driven design subdomain.
- Decompose by verb or use case and define services that are responsible for particular actions. e.g. an authenticating service that’s responsible for authenticating users.
- Decompose by nouns or resources by defining a service that is responsible for all operations on entities/resources of a given type. e.g. a synonyms service that is responsible for giving the synonym of given word.

In our case, we will have the following services

auth-service - It contains the authentication logic using spring security. It creates the Json based Web Tokens(JWT) for the successful authentication. That has to be used in sub sequent other service call for authorisation. It has two types of roles namely normal user and admin user.

antonyms-query-service - It provides the antonym result to the given word. Ideally it should have some DB for keeping the list words and its antonyms results. But I don't want to build any data store for that. So I am going to use the Datamuse for getting antonyms result. This application is developed using Vertx web and it is an asynchronous web service. Zuul service will route the request only for admin user.

sounds-like-query-service - It provides the sounds like result to the given word. Here also I am going to use the Datamuse for getting sounds like result. This application is developed using Spring Boot Web Flux and it is an asynchronous web service.

synonyms-query-service - It provides the synonyms result to the given word. Here also I am going to use the Datamuse for getting synonyms result. This application is developed using Spring Boot Web and it is a synchronous web service.

Data Consistency

We need to maintain the data consistency across services. Maintaining data consistency between services is a challenge because 2 phase-commit/distributed transactions is not an option for many applications. In order to ensure loose coupling, each service has its own database. But for simplicity instead of DB I am going to use the Datamuse as my source of truth.

API Endpoints:

Clients are going to interact with zuul-edge-service for all the calls.

First user has to make the call to auth service with user name and password.

Sample curl script - auth service

http://localhost:8762/api/auth/

For admin user

for admin user

export TOKEN=$(curl -ik -X POST \
  http://localhost:8762/api/auth/ \
  -H 'Content-Type: application/json' \
  -H 'Postman-Token: 922b9352-0bcb-4b1c-ae45-b38da66096a4' \
  -H 'cache-control: no-cache' \
  -d '{"username":"adminuser","password":"12345"}')

For normal user

export TOKEN=$(curl -ik -X POST \
  http://localhost:8762/api/auth/ \
  -H 'Content-Type: application/json' \
  -H 'Postman-Token: 922b9352-0bcb-4b1c-ae45-b38da66096a4' \
  -H 'cache-control: no-cache' \
  -d '{"username":"normaluser","password":"12345"}')

Print the token variable

echo ${TOKEN}

 Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJub3JtYWx1c2VyIiwiYXV0aG9yaXRpZXMiOlsiUk9MRV9VU0VSIl0sImlhdCI6MTU0MTE1NzU0NCwiZXhwIjoxNTQxMjQzOTQ0fQ.suw3USgqZGWQfcYrzvn7m9XnjBv7rpbfQ4C8GE6GWL2Sxlj0fqczxvVQ0Hdd1s8UBK47Ju-47_zA9bz5q5WbFg Transfer-Encoding: chunkedo-store, max-age=0, must-revalidate

Copy the token

Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJub3JtYWx1c2VyIiwiYXV0aG9yaXRpZXMiOlsiUk9MRV9VU0VSIl0sImlhdCI6MTU0MTE1NzU0NCwiZXhwIjoxNTQxMjQzOTQ0fQ.suw3USgqZGWQfcYrzvn7m9XnjBv7rpbfQ4C8GE6GWL2Sxlj0fqczxvVQ0Hdd1s8UBK47Ju-47_zA9bz5q5WbFg

Sample curl script - sounds like service

Sounds like API endpoint using above jwt token: input LUK

http://localhost:8762/api/wqs/soundslike/LUK

curl -X GET   http://localhost:8762/api/wqs/soundslike/LUK   -k --header "Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJub3JtYWx1c2VyIiwiYXV0aG9yaXRpOlsiUk9MRV9VU0VSIl0sImlhdCI6MTU0MTE1NzU0NCwiZXhwIjoxNTQxMjQzOTQ0fQ.suw3USgqZGWQfcYrzvn7m9XnjBv7rpbfQ4C8GE6GWL2Sxlj0fqczxvVQ0Hdd1s8UBK47Ju-47_zA9bz5q5WbFg"

Response: luck

Sample curl script -synonyms service

Synonyms API endpoint using above jwt token: input content

http://localhost:8762/api/wqs/synonyms/content

curl -X GET   http://localhost:8762/api/wqs/synonyms/content  -k --header "Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJub3JtYWx1c2VyIiwiYXV0aG9yaXRpZXMiOlsiUk9MRV9VU0VSIl0sImlhdCI6MTU0MTE1NzU0NCwiZXhwIjoxNTQxMjQzOTQ0fQ.suw3USgqZGWQfcYrzvn7m9XnjBv7rpbfQ4C8GE6GWL2Sxlj0fqczxvVQ0Hdd1s8UBK47Ju-47_zA9bz5q5WbFg"

Response: happy

Sample curl script -antonyms service

Synonyms API endpoint using above jwt token: input content

http://localhost:8762/api/wqs/antonyms/content

curl -X GET   http://localhost:8762/api/wqs/antonyms/content  -k --header "Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJub3JtYWx1c2VyIiwiYXV0aG9yaXRpZXMiOlsiUk9MRV9VU0VSIl0sImlhdCI6MTU0MTE1NzU0NCwiZXhwIjoxNTQxMjQzOTQ0fQ.suw3USgqZGWQfcYrzvn7m9XnjBv7rpbfQ4C8GE6GWL2Sxlj0fqczxvVQ0Hdd1s8UBK47Ju-47_zA9bz5q5WbFg"

Response: 403 Forbidden error since auth token belongs to normaluser.

{
  "timestamp": "2018-11-02T11:34:13.379+0000",
  "status": 403,
  "error": "Forbidden",
  "message": "Forbidden",
  "path": "/api/wqs/antonyms/content"
}

Get the admin auth token using auth endpoint with adminuser

curl -X GET   http://localhost:8762/api/wqs/antonyms/content  -k --header "Authorization: Bearer eyJhbGciOiJIUzUxMiJ9.eyJzdWIiOiJhZG1pbnVzZXIiLCJhdXRob3JpdGllcyI6WyJST0xFX0FETUlOIl0sImlhdCI6MTU0MTE1ODY2MiwiZXhwIjoxNTQxMjQ1MDYyfQ.-PeZebrB5E2RmLk09_W2lyStdsW5dqb8kuPG7GdOLfzAioifas90klXsCGnjM-kchOYR12_01DUHLG72Xp8dDA"

Response: discontent