Welcome!

Microservices Expo Authors: TJ Randall, Liz McMillan, Elizabeth White, Pat Romanski, AppDynamics Blog

Related Topics: Microservices Expo, Java IoT, @DevOpsSummit

Microservices Expo: Blog Feed Post

What Are Microservices? | @DevOpsSummit #Java #Cloud #DevOps #Microservices

Code Examples, Best Practices, Tutorials and More

What Are Microservices?
By Angela Stringfellow

Microservices are increasingly used in the development world as developers work to create larger, more complex applications that are better developed and managed as a combination of smaller services that work cohesively together for larger, application-wide functionality. Tools such as Service Fabric are rising to meet the need to think about and build apps using a piece-by-piece methodology that is, frankly, less mind-boggling than considering the whole of the application at once. Today, we'll take a look at microservices, the benefits of using this capability, and a few code examples.

What Are Microservices?
Microservices is a form of service-oriented architecture style (one of the most important skills for Java developers) wherein applications are built as a collection of different smaller services rather than one whole app. Instead of a monolithic app, you have several independent applications that can run on their own and may be created using different coding or programming languages. Big and complicated applications can be made up of simpler and independent programs that are executable by themselves. These smaller programs are grouped together to deliver all the functionalities of the big, monolithic app.

Microservices captures your business scenario, answering the question "What problem are you trying to solve?" It is usually developed by an engineering team with only a few members and can be written in any programming language as well as utilize any framework. Each of the involved programs is independently versioned, executed, and scaled. These microservices can interact with other microservices and can have unique URLs or names while being always available and consistent even when failures are experienced.

What Are the Benefits of Microservices?
There are several benefits to using microservices. For one, because these smaller applications are not dependent on the same coding language, the developers can use the programming language that they are most familiar with. That helps developers come up with a program faster with lower costs and fewer bugs. The agility and low costs can also come from being able to reuse these smaller programs on other projects, making it more efficient.

Examples of Microservices Frameworks for Java
There are several microservices frameworks that you can use for developing for Java. Some of these are:

  • Spring Boot. This is probably the best Java microservices framework that works on top of languages for Inversion of Control, Aspect Oriented Programming, and others.
  • Jersey. This open source framework supports JAX-RS APIs in Java is very easy to use.
  • Swagger. Helps you in documenting API as well as gives you a development portal, which allows users to test your APIs.

Others that you can consider include: Dropwizard, Ninja Web Framework, Play Framework, RestExpress, Restlet, Restx, and Spark Framework.

How to Create Using Dropwizard
DropWizard pulls together mature and stable Java libraries in lightweight packages that you can use for your own applications. It uses Jetty for HTTP, Jersey for REST, and Jackson for JSON, along with Metrics, Guava, Logback, Hibernate Validator, Apache HttpClient, Liquibase, Mustache, Joda Time, and Freemarker.

You can set up Dropwizard application using Maven. How?

In your POM, add in a dropwizard.version property using the latest version of DropWizard.

<properties>
<dropwizard.version>LATEST VERSION</dropwizard.version>
</properties>
Then list the dropwizard-core library:
<dependencies>
<dependency>
<groupId>io.dropwizard</groupId>
<artifactId>dropwizard-core</artifactId>
<version>${version}</version>
</dependency>
</dependencies>

This will set up a Maven project for you. From here, you can create a configuration class, an application class, a representation class, a resource class, or a health check, and you can also build Fat JARS, then run your application.

Check out the Dropwizard user manual at this link. The Github library is here.

Sample code:

package com.example.helloworld;
import com.yammer.dropwizard.config.Configuration;
import com.fasterxml.jackson.annotation.JsonProperty;
import org.hibernate.validator.constraints.NotEmpty;
public class HelloWorldConfiguration extends Configuration {
@NotEmpty
@JsonProperty
private String template;
@NotEmpty
@JsonProperty
private String defaultName = "Stranger";
public String getTemplate() {
return template;
}
public String getDefaultName() {
return defaultName;
}
}

Microservices with Spring Boot
Spring Boot gives you Java application to use with your own apps via an embedded server. It uses Tomcat, so you do not have to use Java EE containers. A sample Spring Boot tutorial is at this link.

You can find all Spring Boot projects here, and you will realize that Spring Boot has all the infrastructures that your applications need. It does not matter if you are writing apps for security, configuration, or big data; there is a Spring Boot project for it.

Spring Boot projects include:

  • Spring IO Platform: Enterprise grade distribution for versioned applications.
  • Spring Framework: For transaction management, dependency injection, data access, messaging, and web apps.
  • Spring Cloud: For distributed systems and used for building or deploying your microservices.
  • Spring Data: For microservices that are related to data access, be it map-reduce, relational or non-relational.
  • Spring Batch: For high levels of batch operations.
  • Spring Security: For authorization and authentication support.
  • Spring REST Docs: For documenting RESTful services.
  • Spring Social: For connecting to social media APIs.
  • Spring Mobile: For mobile Web apps.

Sample code:

import org.springframework.boot.*;
import org.springframework.boot.autoconfigure.*;
import org.springframework.stereotype.*;
import org.springframework.web.bind.annotation.*;
@RestController
@EnableAutoConfiguration
public class Example {
@RequestMapping("/")
String home() {
return "Hello World!";
}
public static void main(String[] args) throws Exception {
SpringApplication.run(Example.class, args);
}
}

Jersey
Jersey RESTful framework is open source, and it is based on JAX-RS specification. Jersey's applications can extend existing JAX-RS implementations and add features and utilities that would make RESTful services simpler, as well as making client development easier.

The best thing about Jersey is that it has great documentation that is filled with examples. It is also fast and has extremely easy routing.

The documentation on how to get started with Jersey is at this link, while more documentation can be found here.

A sample code that you can try:

package org.glassfish.jersey.examples.helloworld;
import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;

@Path("helloworld")
public class HelloWorldResource {
public static final String CLICHED_MESSAGE = "Hello World!";

@GET
@Produces("text/plain")
public String getHello() {
return CLICHED_MESSAGE;
}
}

Jersey is very easy to use with other libraries, such as Netty or Grizzly, and it supports asynchronous connections. It does not need servlet containers. It does, however, have an unpolished dependency injection implementation.

Play Framework
Play Framework gives you an easier way to build, create and deploy Web applications using Scala and Java. Play Framework is ideal for RESTful application that requires you to handle remote calls in parallel. It is also very modular and supports async. Play Framework also has one of the biggest communities out of all microservices frameworks.

Sample code you can try:

package controllers;

import play.mvc.*;

public class Application extends Controller {

public static void index() {
render();
}

public static void sayHello(String myName) {
render(myName);
}

}

Restlet
Restlet helps developers create fast and scalable Web APIs that adheres to the RESTful architecture pattern. It has good routing and filtering, and available for Java SE/EE, OSGi, Google AppEngine (part of Google Compute), Android, and other major platforms.

Restlet comes with a steep learning curve that is made worse by a closed community, but you can probably get help from people at StackOverflow.

Sample code:

package firstSteps;
import org.restlet.resource.Get;
import org.restlet.resource.ServerResource;
/**
* Resource which has only one representation.
*/
public class HelloWorldResource extends ServerResource {
@Get
public String represent() {
return "hello, world";
}
}

Additional Resources and Tutorials on Microservices
For further reading and information on microservices, including some helpful tutorials, visit the following resources:

The post What are Microservices? Code Examples, Best Practices, Tutorials and More appeared first on Stackify.

Read the original blog entry...

More Stories By Stackify Blog

Stackify offers the only developers-friendly solution that fully integrates error and log management with application performance monitoring and management. Allowing you to easily isolate issues, identify what needs to be fixed quicker and focus your efforts – Support less, Code more. Stackify provides software developers, operations and support managers with an innovative cloud based solution that gives them DevOps insight and allows them to monitor, detect and resolve application issues before they affect the business to ensure a better end user experience. Start your free trial now stackify.com

Microservices Articles
At its core DevOps is all about collaboration. The lines of communication must be opened and it takes some effort to ensure that they stay that way. It’s easy to pay lip service to trends and talk about implementing new methodologies, but without action, real benefits cannot be realized. Success requires planning, advocates empowered to effect change, and, of course, the right tooling. To bring about a cultural shift it’s important to share challenges. In simple terms, ensuring that everyone k...
Is advanced scheduling in Kubernetes achievable?Yes, however, how do you properly accommodate every real-life scenario that a Kubernetes user might encounter? How do you leverage advanced scheduling techniques to shape and describe each scenario in easy-to-use rules and configurations? In his session at @DevOpsSummit at 21st Cloud Expo, Oleg Chunikhin, CTO at Kublr, answered these questions and demonstrated techniques for implementing advanced scheduling. For example, using spot instances and co...
Today most companies are adopting or evaluating container technology - Docker in particular - to speed up application deployment, drive down cost, ease management and make application delivery more flexible overall. As with most new architectures, this dream takes significant work to become a reality. Even when you do get your application componentized enough and packaged properly, there are still challenges for DevOps teams to making the shift to continuous delivery and achieving that reducti...
Skeuomorphism usually means retaining existing design cues in something new that doesn’t actually need them. However, the concept of skeuomorphism can be thought of as relating more broadly to applying existing patterns to new technologies that, in fact, cry out for new approaches. In his session at DevOps Summit, Gordon Haff, Senior Cloud Strategy Marketing and Evangelism Manager at Red Hat, discussed why containers should be paired with new architectural practices such as microservices rathe...
With the rise of Docker, Kubernetes, and other container technologies, the growth of microservices has skyrocketed among dev teams looking to innovate on a faster release cycle. This has enabled teams to finally realize their DevOps goals to ship and iterate quickly in a continuous delivery model. Why containers are growing in popularity is no surprise — they’re extremely easy to spin up or down, but come with an unforeseen issue. However, without the right foresight, DevOps and IT teams may lo...
Kubernetes is a new and revolutionary open-sourced system for managing containers across multiple hosts in a cluster. Ansible is a simple IT automation tool for just about any requirement for reproducible environments. In his session at @DevOpsSummit at 18th Cloud Expo, Patrick Galbraith, a principal engineer at HPE, will discuss how to build a fully functional Kubernetes cluster on a number of virtual machines or bare-metal hosts. Also included will be a brief demonstration of running a Galer...
DevOps is under attack because developers don’t want to mess with infrastructure. They will happily own their code into production, but want to use platforms instead of raw automation. That’s changing the landscape that we understand as DevOps with both architecture concepts (CloudNative) and process redefinition (SRE). Rob Hirschfeld’s recent work in Kubernetes operations has led to the conclusion that containers and related platforms have changed the way we should be thinking about DevOps and...
In his session at 20th Cloud Expo, Mike Johnston, an infrastructure engineer at Supergiant.io, will discuss how to use Kubernetes to setup a SaaS infrastructure for your business. Mike Johnston is an infrastructure engineer at Supergiant.io with over 12 years of experience designing, deploying, and maintaining server and workstation infrastructure at all scales. He has experience with brick and mortar data centers as well as cloud providers like Digital Ocean, Amazon Web Services, and Rackspace....
"There is a huge interest in Kubernetes. People are now starting to use Kubernetes and implement it," stated Sebastian Scheele, co-founder of Loodse, in this SYS-CON.tv interview at DevOps at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Modern software design has fundamentally changed how we manage applications, causing many to turn to containers as the new virtual machine for resource management. As container adoption grows beyond stateless applications to stateful workloads, the need for persistent storage is foundational - something customers routinely cite as a top pain point. In his session at @DevOpsSummit at 21st Cloud Expo, Bill Borsari, Head of Systems Engineering at Datera, explored how organizations can reap the bene...