dongliutony / my-mini-coupon

my-mini-coupon

This is a Spring Cloud microservice project for coupon management.

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1. environment

Below are the workable versions, and higher versions may need to do some double check to make things work together.

• java 8
• Spring Cloud Greenwich.SR6
• SpringBoot 2.1.10.RELEASE
• MySQL 8.0.32
• Redis 6.0
• Kafka 2.2.2

2. Spring Cloud modules

• coupon-eureka:
• coupon-gateway:

3. business services

1. coupon-common

   for shared code base, configuration, response, and exception handling across the project

2. coupon-template

   1. build coupon-template:
   2. generate coupon-code:
   3. clean expired coupon-template:

3. coupon-distribution

   1. fetch a user's coupon records:
   2. fetch a user's applicable coupons:
   3. user apply coupons:
   4. pre-calculate/use a coupon:

4. coupon-settlement

   1. calculate with coupons:

5. coupon-permission

   1. path cration:

      Add other microservice controller's URL/path into permission module. It provides APIs to offload such management from developers to PM or operation teams.

      fas 
      

   2. permission validation:

4. how to set up environment

1. boot up MySQL, and create db and tables
2. boot up Redis: redis-server on a server, or run it in a docker container
3. boot up Kafka: run it on a server
   • run zookeeper first /kafka_directory/bin/zookeeper-server-start.sh -daemon config/zookeeper.properties
   • use jpa and check if zookeeper Java ps is ready
   • run kafka when zookeeper is ready nohup /kafka_directory/bin/kafka-server-start.sh config/server.properties &
4. boot up Eureka: For Eureka server cluster deployment on one server node, run mvn clean package -Dmaven.test.skip=true -U to build jar, add items with format 127.0.0.1 eureka-server1 in the /etc/hosts file (make sure that a microservice's application.yml has configuration like eureka: client: service-url: defaultZone: http://eureka-server1:8001/eureka/). Then run java -jar coupon-eureka-1.0-SNAPSHOP.jar --spring.profiles.active=eureka-server1 to boot up 1st node, then boot up the rest.
5. boot up Zuul:

5. how to run business service modules

1) run modules separately

1. install coupon-common: it needs to be installed to local .m2 directory so that other modules can use it - navigate to coupon-common root direct and run mvn clean install to install it into local .m2.
2. start basic services: mysql, redis, and kafka
3. package spring cloud services: run mvn clean build -Dspring.active.profile=prod --skip-test=true for coupon-eureka, coupon-gateway and run the jar files with java -jar xx.jar.
4. package business modules: package all the business microservices and run jar files respectively

2) run modules with docker composer

6. how to develop a module

1) think about the business logic and feature requirements

2) design data structure, database schema, and cache KV

3) design code architecture

4) start to code

7. key techniques

• Spring Cloud architecture

• SpringBoot & Starter

• universal Response Advice & Exception Handler

• JPA, Field converter, & object serialization

  • JPA is the standard for ORM, while Hibernate is an implementation. We write JPA interface and let AOP do the magic.

  // define entity and PrimaryKey type, JPA will do the match and query.
  public interface CouponTemplateDao extends JpaRepository<CouponTemplate, Integer> {
         
       CouponTemplate findByName(String name);
    
       // params math method names respectivelv. e.g ByAvailable -> available, Expired -> expired
       List<CouponTemplate> findAllByAvailableAndExpired(Boolean available, Boolean expired);
    
       List<CouponTemplate> findAllByExpired(Boolean expired);
  }
  

  • Entity's partArgsConstructor: we normally define ID as a PrimaryKey and created by db, not by entity constructor.

• Feign, inter modules communication, SDK, and VO

• Async tasks

• Scheduling tasks

• Redis

• Kafka

• Bean Post Processor (BPP)

• Spring eventListener

• integration test environment for Spring Cloud project

• some pitfalls

  1. All packages in different module should have the same name. Otherwise, Spring cannot scan and manage the beans in a different package than your working package.
  2. Version compatible: SpringCloud vs SpringBoot version matrix. MySQL and connector version

8. plans

• enhance gateway with more filters: check by url to do validation, query result cache, etc
• custom Kafka pipeline: directly send KafkaMessage into MQ without manually serialize/deserialize ops.
• enhance validation
• request tracing
• in-memory db, redis, kafka for Unittest
• distributed logging ELK
• monitor module
• docker composer configuration
• front end