Getting Started With Microservices Pranav Kumar 

Agenda ● Why Microservice ? ● What is Microservice ? ● What do we( Developer,Architect, Business..etc) need ? ● Technology Comparison ● Microservice Features ● Spring Boot Features ● Microservice Communication ● Testing ● Demo 

Why ? 

Problem with Monolithic Architecture ➔ Tightly Coupled ➔ Language dependency ➔ Scalability ➔ Root Cause Analysis ➔ Monitoring ➔ Auditing ➔ Performance Management Integration Layer (Business Logic) Catalog Query Parts Pricing & Availabilit y Quotatio n Order Order Track ORM Database Pricing 

What ? ➔ Software Architecture Style ➔ Loosely coupled ➔ Language Agnostic ➔ Highly Scalable Catalog ORM Database 

What ? “Microservices is a way of breaking large software projects into smaller, independent, and loosely coupled modules. Individual modules are responsible for highly defined and discrete tasks and communicate with other modules through simple, universally accessible APIs.” 

What do we need ? 

Software/Service ● Loosely coupled ● Rest Support ● Transaction Management ● Log Management ● Auditing ● Scalable ● Secure ● Statistics We need.. 

Technologies.. Comparison Rest Support Embedded Container Statistics Support Log Management Transaction Management Security DropWizard ✓ ✓ ✓ ✓ ✕ ✓ Spring Boot ✓ ✓ ✓ ✓ ✓ ✓ Apache Karaf ✓ ✓ ✕ ✕ ✓ ✓ Jersey ✓ ✓ ✓ ✓ ✕ ✓ Apache CXF ✓ ✓ ✓ ✓ ✓ ✓ 

Microservice Features 

Coupling Microservices definitions says that “Microservices is a way of breaking large software projects into smaller, independent, and loosely coupled modules” So, this issue is straightaway solved. Catalog ORM Database Query Parts ORM Database 

Language Independent Each service can be developed using different programming language Allows you to take advantage of emerging and latest technologies (framework, programming language , programming practice, etc.). Catalog( Spring Boot ) Spring Data NoSql Query Parts( Apache Karaf ) Hibernate RDBMS 

Scalability Since microservices are very small part of the complete software ecosystem, It is very easy to scale the same. Unlike, the monolithic web application, where if we have to do a scaling, first we have to setup the environment ( apache, tomcat ) and then deploy the war/ear files in that. 

Scalability with monolithic ... Integration Layer (Business Logic) Catalog Query Parts Pricing & Availabi lity Quotat ion Order Order Track ORM Database Pricing Integration Layer (Business Logic) Catalog Query Parts Pricing & Availabi lity Quotat ion Order Order Track ORM Database 

Scalability with Microservice Catalog ORM Database Query Parts ORM Database Catalog ORM Database 

Root Cause Analysis It is always difficult to find the root cause in a Single Large Monolithic system. In microservice, fault isolation would be improved and we can easily identify which service is consuming more memory or cpu and we can scale that service easily and fix the issue ( if any ) later. 

Spring Boot 

Logging Strategy Spring Boot provides us the various way to achieve logging ➔ Using Aspect ➔ Using logback ➔ Annotation based logging ( When an exception occurs ) 

@Before("execution(* com.wtc.samplems.controller.*.*(..))") public void logServicebefore(JoinPoint joinPoint) { logger.debug("Completed: " + joinPoint); System.out.println( "Completed: " + joinPoint ); } Annotation ( Handling Exception and log ): @ExceptionHandler(Exception.class) @ResponseStatus(HttpStatus.INTERNAL_SERVER_ERROR) public @ResponseBody JSONObject handleException(Exception e, HttpServletRequest request) { JSONObject jSONObject = new JSONObject(); jSONObject.put(ConstantsUtility.STATUS, ConstantsUtility.FAILED); UtilityLogger.error("Request Processing Failed in Navigation Serv "+e.getMessage()); return jSONObject; } AspectJ: 

UTF-8 ./logs/servive.log %d ${logger.type} %p %m%n 10 ./logs/navigationservices.log.%i 1MB %d ${logger.type} %p %m%n utf8 Logback: 

Monitoring Spring boot comes with it’s own monitoring tool called “Spring Admin Console” We can monitor various aspects like: ➔ Application health ➔ Memory ➔ JVM ➔ Garbage Collection ➔ Metrics etc.. We can also changelog level without restarting of the application. This would help us in debugging any prod issue Sample UI : https://github.com/codecentric/spring-boot-admin 

Dashboard with Desktop Notifications 

View Application Health, Information & Details 

View Metric Counters 

Manage Logback logger levels 

Auditing Auditing would be achieved using AspectJ We can have the information like ➔ Who accessed the URL and from where ➔ How many requests have been successfully served to whom and how many got failed ➔ Which services - How many times - By Whom 

Performance Management Until now, We are using several tools to perform this task ● Jconsole ● JvisualVM ● Java Mission Control ( Comes with Java 8 ) ● Logicmonitor (Paid) 

Performance Management Every time a new developer/user comes to the environment, we have to educate them to understand each of the tool. Spring Boot gives us a single tool ( Spring Admin Console) to do the performance management as well 

Transaction Management Spring gives us various ways to manage the transactions, In which two of them are very popular : ➔ Using Aspects ➔ Annotation Based 

Using Aspect 

@Transactional public class DefaultFooService implements FooService { Foo getFoo(String fooName); Foo getFoo(String fooName, String barName); . . } Annotation 

Communication External : Using REST Internal : Using REST 

Testing - Unit testing - Junit - Integration Testing - Rest Client - Postman 

Demo 

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