springcloud-microservices

Microservices implemented through spring cloud and spring boot

About this Project:

This project contains Multiple modules demonstrating different aspects of cloud and the quick details can be found as below:

• springcloud-m1-startup
• springcloud-m2-config-client
• springcloud-m2-configserver
• springcloud-m2-configserver-git
• springcloud-m3-task
• springcloud-m4-secureservice
• springcloud-m4-secureui

Technology stack used summary

Spring Boot
Spring Boot makes it easy to create stand-alone, production-grade Spring based Applications that you can “just run”. We take an opinionated view of the Spring platform and third-party libraries so you can get started with minimum fuss. Most Spring Boot applications need very little Spring configuration. You can use Spring Boot to create Java applications that can be started using java -jar or more traditional war deployments. We also provide a command line tool that runs “spring scripts”.

Our primary goals are:

• Provide a radically faster and widely accessible getting started experience for all Spring development.
• Be opinionated out of the box, but get out of the way quickly as requirements start to diverge from the defaults.
• Provide a range of non-functional features that are common to large classes of projects (e.g. embedded servers, security, metrics, health checks, externalized configuration).
• Absolutely no code generation and no requirement for XML configuration

Spring Boot Actuator
It is a sub-project of Spring Boot. It adds several production grade services to your application with little effort on your part

Spring cloud (cloud.spring.io) Spring Cloud provides tools for developers to quickly build some of the common patterns in distributed systems (e.g. configuration management, service discovery, circuit breakers, intelligent routing, micro-proxy, control bus, one-time tokens, global locks, leadership election, distributed sessions, cluster state). Coordination of distributed systems leads to boiler plate patterns, and using Spring Cloud developers can quickly stand up services and applications that implement those patterns. They will work well in any distributed environment, including the developer's own laptop, bare metal data centres, and managed platforms such as Cloud Foundry.

Spring cloud catalog

* Spring Cloud Config : Git-backed configuration server
* Spring Cloud Netflix : Suite for service discovery,routing, availability
* Spring Cloud Consul : Service discovery with Consul
* SpringCloud Security : Simplify OAuth 2.0 flows
* Spring Cloud Sleuth : Distributed tracing
* Spring Cloud Stream : Messagebus abstraction
* Spring Cloud Task : Short-lived, single-task microservices
* SpringCloud Dataflow : Orchestrationof data microservices
* Spring Cloud Zookeeper : Servicediscovery and configuration with Zookeeper
* Spring Cloud for AWS : Exposes core AWS services to Spring developers
* Spring Cloud Spinnaker : Multi-cloud deployment
* Spring Cloud Contract : Stubs for service contracts

Prerequisites

1. STS: http://spring.io/tools/sts (3.8.4 as on 17/06/2017)
   The Spring Tool Suite is an Eclipse-based development environment that is customized for developing Spring applications.
   Note: Download STS according to your OS i.e 32 bit or 64 Bit else you might get "Java was started but returned exit code=13"

2. 7Zip: http://www.7-zip.org/
   To unzip the STS package you just downloaded above. While unzipping with Winzip you may get the "path too long for folder" error. And to avoid this unzip via 7Zip.

3. Postman: https://www.getpostman.com/
   A powerful GUI platform to make your API development faster & easier, from building API requests through testing
   Note: (download exe and it requires .NET to be installed in your system or you can add plugin in chrome)

4. Vagrant: https://www.vagrantup.com/downloads.html
   It provides virtual environment for application to run. Vagrant provides the same, easy workflow regardless of your role as a developer, operator, or designer. It leverages a declarative configuration file which describes all your software requirements, packages, operating system configuration, users, and more.
   Docker: An alternative for Vagrant.

5. RabbitMQ: https://www.rabbitmq.com/install-windows.html , http://www.erlang.org/download.html
   From wiki : RabbitMQ is open source message broker software (sometimes called message-oriented middleware) that implements the Advanced Message Queuing Protocol (AMQP). The RabbitMQ server is written in the Erlang programming language and is built on the Open Telecom Platform framework for clustering and failover. Client libraries to interface with the broker are available for all major programming languages.
   Note: We can also install image of RabbitMQ and MySql on Vagrant or Docker

6. Java: http://www.oracle.com/technetwork/java/javase/downloads/jre8-downloads-2133155.html
   Download JAVA 8, as it is mandatory requirement for STS
   Install the JDK > Setup "JAVA_Home" System variable Right click on Control panel > Advanced system settings > Environment variables > New)and set this in Path variable.
   Eg: JAVA_HOME - C:\Program Files\Java\jdk1.8.0_73
   Check: java -version

7. Maven: http://maven.apache.org/download.cgi
   Download the Binary folder > Setup "M2_Home" environment variable and set this in Path variable.
   Note: Setting up Java is mandatory for maven.
   EG: M2_Home - C:\Maven\apache-maven-3.3.1-bin\apache-maven-3.3.1
   check: mvn -version
   Gradle: An alternative for Maven.

Workspace

Create a new workspace folder if you are switching from Eclipse,IntelliJ or any other IDE to STS. As all the IDEs have there specific settings inside the Workspace folder it is good if we start with a clean slate.

Spring Starter Project (Repeated step for each module creation)

This step will be repeated number of times during the project

• STS -> File -> New -> Spring Starter Project
• Select Java: 8 , Type: Maven(In case you have to use Gradle, you have to install it first before selecting as it will give you error)
• Group: girirajvyasblog.demo (Same as package)
• Artifact: springcloud-startup-module1 (your application name)
• version: populate by default, let it as it is.
• Description: Demo project for Spring Boot (Description about your project)
• package: girirajvyasblog.demo
• Click Next
• Spring Boot Version: 1.5.4(this was at the time of writing, use the latest one)
• Select : spring modules that we want to use. (mostly we will be using Web, Actuator, config-server, config-client)
• Click Finish

It will take some time to get all the dependencies downloaded on your local machine. It is done by maven which reads pom.xml and resolves the dependencies.

The entry that does almost all the autoconfiguration is below:

	<parent>
		<groupId>org.springframework.boot</groupId>
		<artifactId>spring-boot-starter-parent</artifactId>
		<version>1.5.4.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>

1. Project 1 : springcloud-m1-startup

This is just for getting started with spring-boot. We will try to create a REST Webservice and try to test it with POSTMAN

a. Create Spring Starter Project with below values
Group: girirajvyasblog.demo (Same as package)
Artifact: springcloud-startup-module1 (your application name)
version: populate by default, let it as it is.
Description: Demo project for Spring Boot (Description about your project)
package: girirajvyasblog.demo

b. Edit application.properties
server.port=8080

c. Edit SpringBoot main class to Add a REST endpoint Annotate class with @RestController
Add method as below

@RequestMapping(value="/greeting", method=RequestMethod.GET)
public String sayHello(){
  return "Hello From Spring Boot";
}

d. View the Actuator endpoints

1. localhost:8080/greeting : this is from the webservice we just created, remaining are from Actuator.
2. localhost:8080/health
3. localhost:8080/beans
4. localhost:8080/env
5. localhost:8080/metrics
6. localhost:8080/mappings
7. localhost:8080/trace
   Note: You can also find the Url patterns during the server startup.

2. Project 2.A : springcloud-configserver-module2

There are two ways in which we can create config server.

• locally through the Local files
• Using the git repository. In this project we will do Local file based config server. Lets see the important points of both the approaches before we start

Local Files	Git-base Repository
Points to classpath or file system	Points to git repo
Multiple search locations possible	Multiple search locations possible
No audit trail	Full change history
Supports labelling	Supports labelling
Support for placeholders in URI	Support for placeholders in URI
Relies on “native” profile	Multiple profiles possible
Dev/test only, unless set up in reliable, shared fashion	Local git for dev/test highly available file system or service for production

This project is related to local file configurations and git repository part will see on next project. Steps Summary:

a. Use start.spring.io, Spring Tool Suite or chosen IDE to generate scaffolding
b. See POM dependency on spring-cloud-config-serverand spring-boot-starter-actuator.
c. Add @EnableConfigServerannotation to class.
d. Create application properties (or YAML) with server port, app name, and profile.

Detailed Process Step 1: Setup
Setting up File > New > Spring Starter Project
Select Java: 8
Type: Maven(In case you have to use Gradle, you have to install it first before selecting as it will give you error)
Group: girirajvyasblog.demo (Same as package)
Artifact: springcloud-configserver-module2 (your application name)
version: populate by default, let it as it is.
Description: testing out spring config server package: girirajvyasblog.demo Click Next -> Spring Boot Version: 1.5.4 Select : Config server, Actuator -> Click Next -> Finish

Step 2: Change in files
Anotate main file with @EnableConfigServer.
Go to src > main > resources and create new folder config (default path to look for resources)
Create 3 property files namely app1.properties, app2.properties, app3.properties.
Add key greeting with different value in each property file.

In Application.properties file > server.port=8888 spring.profiles.active=native

Start the boot app

Step 3: Test
localhost:8888/app1/default
localhost:8888/app2/default
localhost:8888/app3/default

3. Project 2.B : springcloud-configserver-module2-git

This project is related to Git-base Repository configurations

a. create git repo to save all the configs
b. @EnableConfigServer in main Application file
c. Add encrypt key in bootstrap.properties -> encrypt.key=ABCDEFGHIJKLMNOPQRSTUVWXYZ

4. Project 3 : springcloud-config-client-module2

Test
http://localhost:8080/rate
Here, It will load all the properties from the git config server

References:

Tutorial from : Richard Seroter

GIT

For Github flavored markdown:

• https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet
• https://guides.github.com/features/mastering-markdown/

Adding new Repository via Git Bash (it is not possible to do it with Egit plugin)

• https://help.github.com/articles/adding-an-existing-project-to-github-using-the-command-line/

Spring Spring Boot Actuator

• https://spring.io/guides/gs/actuator-service/
• http://docs.spring.io/spring-boot/docs/current/reference/htmlsingle/#production-ready

Spring cloud

• http://projects.spring.io/spring-cloud/

Spring cloud security

• http://cloud.spring.io/spring-cloud-security/spring-cloud-security.html