Micro service template

This is a template project to create a micro service in a standardized manner. Basic ideas for Maven dependency management, Spring framework (DI, Spring Boot, RestTemplate etc.), Netflix microservice concepts (Eureka, Ribbon, Hysterix) are kind of pre-requisites for delving into world of micro-services. Final deliverable of the command 'mvn clean install' on a template project (or any microservice based on it) would be a single jar file. This jar file would have all its dependencies embedded inside and when ran with a simple java command, it will start an embedded tomcat to expose all defined REST endpoints. This jar would go inside a docker image and that docker image can be installed on any OS. Please lookup Dockerization for more.

Typically, a usual microservice has an architecture like this:

Project features

This project demoes the following moving parts to be used for the development of any new micro service

• Self-Registration to a Eureka server
• Circuit breaker / Hystrix (/demoHysterix endpoint exhibit this)
• Spring Data with Hibernate (service makes DB calls for its CRUD operations)
• Redis client (fmsTemplateAccount caches account entity, endpoint /cacheable/owner/{name} uses spring annotations, /cachingWithoutAnnotation/owner/{name} does it without using any annotation to display both modes of communication with cache)
• Kafka client and consumer (service sends a message to kafka and also receives it using a listener. See /demoKafka endpoint)
• Audit using AOP - client IP, Method arguments, Response value, response time , trackId (exhibits all these using LogDocTrackConfig class)
• Unit test case sample class AccountsControllerTest
• Please note that the controller APIs are not RESTful as these are just for demo purpose.

Project details

1. AccountsServer, the starting point
   • It starts the spring boot app.
   • It starts an embedded tomcat server.
   • Looks for accounts-server.properties file, in which we define app name, port number, eureka URL etc.
   • It enables
     • EurekaClient
     • CircuitBreaker (Hysterix)
     • Redis Caching
     • Database connectivity. Searches for Property file classpath:database.properties, Looks for all the table entities through @EntityScan(com.org.fms.account.model), Looks for all the JPA repositories and queries etc. through @EnableJpaRepositories(com.org.fms.account.model)
     • @RestController, @Services, @Components etc. by scanning packages under com.org.fms.account.
     • A REST template for making REST calls
2. AccountsController
   • Has a normal GET
   • Has a GET, PUT and DELETE to demo caching techniques
   • Has a GET to demo hysterix fallback mechanism
3. CacheDemoService has service methods to demo caching techniques
4. HysterixDemoService has service methods to demo hysterix fallback mechanism
5. Account is the DB table equivalent
6. AccountRepository class has all the DB queries embedded inside it, in the form of methods OR queries
7. CacheConfig is used to configure Redis connection etc. It looks for redis.properties in the classpath
8. DBConfig is used to configure Redis connection etc. It looks for sql-server.properties in the classpath
9. KafkaConfig is used to configure Kafka 0.9.0.1 connection etc. It looks for kafka.properties in the classpath
10. LogDocTrackConfig configures swagger documentation, enables incoming request tracking, creates performance logs and adds request track id in logs. It looks for swagger.properties in the classpath.
11. logback.xml defines how service logs should be created.

What to do when referencing this project

1. Copy project structure, pom.xml, LogDocTrackConfig, swagger.properties and logback.xml. Tweak swagger.properties and logback.xml as per your documentation and logging requirements. If Performance logs are required, change the value of PERF_LOG_SCOPE variable in LogDocTrackConfig class as per your performance logging needs.
2. For Caching needs, copy CacheConfig and redis.properties. Tweak cache.properties for connection configuration. If Caching is not required, you may also remove dependency spring-boot-starter-redis from pom file
3. For Database needs, copy DBConfig and sql-server.properties. Tweak sql-server.properties for connection configuration. Also change the package names in DBConfig class for @EntityScan and @EnableJpaRepositories annotations. If Database is not required, you may also remove dependencies (spring-data-commons,spring-boot-starter-data-jpa,jtds,c3p0) from pom file
4. For Kafka needs, copy KafkaConfig and kafka.properties. If Kafka is not required, you may also remove dependencies (spring-kafka) from pom file
5. Create Server , Controller, Service, Model, JPA classes and server bootup properties file on the same lines, naming conventions, annotations etc.